LTE Fundamentals - Course Documentation 2010

LTE Fundamentals

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LTE Fundamentals Course documentation December 2010

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LTE Fundamentals

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© 2010 PontoTech

LTE Fundamentals

LTE Fundamentals

COURSE CONTENTS LTE FUNDAMENTALS ...................................................................................................................................... 3 1

EVOLUTION AND TRENDS OF MOBILE TELEPHONY ....................................................................................... 7 1.1 Introduction ......................................................................................................................................... 8 1.2 Importance of mobility in telecommunications .................................................................................... 9 1.3 Increased demand for mobile data services ........................................................................................ 9 1.3.1 1.3.2

1.4

Evolution of mobile terminals to the increased demand for data .................................................................... 10 The phenomenon of Smartphone .................................................................................................................... 11

Evolution of communications to mobile broadband .......................................................................... 12

1.4.1

1.5 1.6

NGN as a principle to evolve towards broadband........................................................................................... 13

Evolution generation mobile networks .............................................................................................. 15 Towards the Fourth Generation (4G)................................................................................................ 16

1.6.1

Fourth Generation Technologies..................................................................................................................... 18

1.7 Global demand for mobile access...................................................................................................... 19 2 COMPARISON BETWEEN WIMAX AND LTE ............................................................................................... 23 2.1 WiMAX Technology Overview ........................................................................................................... 24 2.2 LTE Overview .................................................................................................................................... 24 2.3 LTE-Advanced for IMT-Advanced ..................................................................................................... 25 2.4 Technical comparison between LTE and Mobile WiMAX ................................................................. 28 2.5 Interoperability between the two technologies .................................................................................. 29 2.6 Tendency for operators to implement LTE ........................................................................................ 30 3 THIRD-GENERATION NETWORKS AS THE BASIS FOR THE EVOLUTION TO LTE ............................................. 31 3.1 Evolution of a UMTS network to LTE ............................................................................................... 32 3.2 UMTS Network Structure .................................................................................................................. 34 3.2.1 3.2.2

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UTRAN .......................................................................................................................................................... 34 Core network .................................................................................................................................................. 38

STANDARDIZATION AND TECHNICAL REQUIREMENTS ACCORDING TO 3GPP LTE...................................... 43 4.1 Reason for the evolution of the system architecture .......................................................................... 44 4.2 Working groups and the definition of technical specifications for LTE ............................................ 44 4.3 3GPP requirements for LTE .............................................................................................................. 46 4.3.1 4.3.2 4.3.3 4.3.4

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Requirements related to the ability ................................................................................................................. 46 Requirements related to performance ............................................................................................................. 47 Requirements related to network deployment................................................................................................. 48 Requirements for E-UTRAN architecture ...................................................................................................... 49

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4.3.5 4.3.6 4.3.7 4.3.8

4.4 4.5 4.6 4.7

Requirements for radio resource management ............................................................................................... 49 Requirements related to the complexity of the systems.................................................................................. 49 Protocols and services requirements .............................................................................................................. 50 Specifications for interoperability with legacy networks ............................................................................... 50

Standardization beyond Release 8 ..................................................................................................... 52 Architecture Overview of LTE / SAE ................................................................................................. 52 General elements of architecture ....................................................................................................... 54 Particular elements of the architecture ............................................................................................. 56

4.7.1 4.7.2 4.7.3 4.7.4 4.7.5 4.7.6 4.7.7

4.8

The eNodeB ................................................................................................................................................... 56 Entity Mobility Management (MME, Mobile Management Entity) ............................................................... 58 SAE GW ........................................................................................................................................................ 60 Gateway service (S-GW, Serving Gateway) .................................................................................................. 60 Gateway Packet Data Network (P-GW, Packet Data Network Gateway) ...................................................... 62 Feature Collection Policy and Resources (PCRF, Policies and Charging Resource Function) ...................... 64 Local subscriber server (HSS, Home Subscriber Server) ............................................................................... 65

Interfaces and protocols in the setting of the basic system architecture............................................ 66

4.8.1 4.8.2 4.8.3 4.8.4 4.8.5 4.8.6 4.8.7 4.8.8 4.8.9 4.8.10

4.9

System Architecture and E-UTRAN access networks legacy ............................................................. 82

4.9.1 4.9.2

4.10

Interconnection infrastructure architecture Bequeathed LTE 3GPP ............................................................... 82 Interfacing with legacy infrastructure 3GPP CS ............................................................................................ 85

Interconnection Architecture LTE infrastructure Bequeathed No - 3GPP ........................................ 86

4.10.1 4.10.2 4.10.3 4.10.4 4.10.5 4.10.6

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Interface LTE-Uu ........................................................................................................................................... 67 S1-MME interface .......................................................................................................................................... 69 S11 interface .................................................................................................................................................. 70 S5/S8 Interface ............................................................................................................................................... 72 GTP S5/S8 Interface ...................................................................................................................................... 72 PMIP S5/S8 Interface ..................................................................................................................................... 74 Interface X2.................................................................................................................................................... 75 SGI interface .................................................................................................................................................. 76 S6a/S6d Interface ........................................................................................................................................... 78 Rx Interface ............................................................................................................................................... 80

User Equipment ......................................................................................................................................... 87 Evolved Packet Core (EPC) ....................................................................................................................... 88 Non-3GPP access network reliable ............................................................................................................ 89 Access networks unreliable non-3GPP ...................................................................................................... 89 Main elements of the Interconnection System ........................................................................................... 90 Interfaces and protocols for the interconnection of the 3GPP networks .................................................... 90

ASPECTS OF LTE RADIO ............................................................................................................................. 93 5.1 Definition of the radio interface ........................................................................................................ 94 5.1.1 5.1.2 5.1.3 5.1.4 5.1.5 5.1.6

5.2 5.2.1 5.2.2 5.2.3

5.3 5.3.1 5.3.2 5.3.3 5.3.4

Access Technologies ...................................................................................................................................... 94 MIMO (Multiple Input Multiple Output) ..................................................................................................... 100 Element and resource block ......................................................................................................................... 102 Downlink transmission ................................................................................................................................. 102 LTE OFDM cyclic prefix, CP ...................................................................................................................... 104 Uplink transmission technique ..................................................................................................................... 105

Access modes and frequency bands LTE. ........................................................................................ 106 Access Modes .............................................................................................................................................. 106 Supported frequency bands. ......................................................................................................................... 108 Bandwidth of transmission ........................................................................................................................... 108

Radio layers and protocols used in LTE .......................................................................................... 110 Radio Link Control (RLC) ........................................................................................................................... 112 Media Access Control (MAC) ..................................................................................................................... 113 Logical channels and transport channels. ..................................................................................................... 114 Physical Layer .............................................................................................................................................. 116

5.4 Frame structure ............................................................................................................................... 121 5.5 Modulation....................................................................................................................................... 123 5.6 Data Flow ........................................................................................................................................ 124 5.7 EU states and zone concepts ............................................................................................................ 125 5.8 Rates of end user data, EU capabilities ........................................................................................... 126 6 CONSIDERATIONS FOR LTE RADIO SPECTRUM......................................................................................... 129 6.1 Overview of Radio Spectrum ........................................................................................................... 130 6.2 Actors involved in spectrum management ....................................................................................... 131 6.3 LTE spectral efficiency .................................................................................................................... 132

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6.4

Spectrum bands allocated for LTE .................................................................................................. 133

6.4.1 6.4.2 6.4.3

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Frequency bands currently used for LTE ...................................................................................................... 133 Aspects to consider when choosing the frequency of implementation ......................................................... 134 The choice of refarming as an alternative implementation ........................................................................... 137

6.5 Amount of spectrum required for LTE deployment.......................................................................... 138 OTHER CONSIDERATIONS ON A MIGRATION TO LTE ................................................................................. 139 7.1 Special considerations must take into account an operator ............................................................ 142 7.1.1 7.1.2 7.1.3 7.1.4 7.1.5 7.1.6 7.1.7 7.1.8

7.2

Considerations for network planning ............................................................................................................ 142 Initiation stage .............................................................................................................................................. 143 Stage details .................................................................................................................................................. 143 Optimization stage ........................................................................................................................................ 143 Deploying services over LTE ....................................................................................................................... 144 Voice over LTE ............................................................................................................................................ 150 Circuit switch fallback (CS fallback) ............................................................................................................ 150 Solution VoLGA........................................................................................................................................... 152

Offer LTE-capable terminals to allow for QoE ............................................................................... 155

7.2.1 7.2.2 7.2.3

7.3

Election of the terminal (UE)........................................................................................................................ 155 Multimode terminals..................................................................................................................................... 156 Multiband terminals ...................................................................................................................................... 156

Quality of Service (QoS) .................................................................................................................. 157

7.3.1 7.3.2 7.3.3 7.3.4 7.3.5

7.4 7.5 7.6

EPS architecture and quality of service ........................................................................................................ 157 EPS Carrier ................................................................................................................................................... 158 QoS parameters............................................................................................................................................. 160 Packet Filters ................................................................................................................................................ 162 Mapping the QoS parameters for UMTS and EPS ....................................................................................... 162

Implementing a solution SON (Self Optimizing Network) to support efficiency .............................. 164 Reuse of access equipment .............................................................................................................. 164 Reuse and improvement of network backbone and backhaul transport .......................................... 166

7.6.1 7.6.2

7.7

Evolution LTE backhaul ............................................................................................................................... 168 Transport backhaul technologies LTE .......................................................................................................... 170

Summary of proposed technical requirements for deploying LTE .................................................. 172

7.7.1 7.7.2 7.7.3 7.7.4 7.7.5 7.7.6 7.7.7 7.7.8 7.7.9 7.7.10

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LTE BUSINESS PERSPECTIVES .................................................................................................................. 185 8.1 Global trend in demand for data ..................................................................................................... 186 8.2 LTE as a data access solution ......................................................................................................... 190 8.3 Operators Initiatives ........................................................................................................................ 192 8.3.1 8.3.2 8.3.3

8.4

Operators in Asia .......................................................................................................................................... 195 Operators in Europe ...................................................................................................................................... 195 Operators in Latin America and the United States ........................................................................................ 196

Initiatives manufacturers ................................................................................................................. 198

8.4.1 8.4.2 8.4.3 8.4.4 8.4.5 8.4.6

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Frequency bands for equipment .................................................................................................................... 172 Modifications to the data network ................................................................................................................ 173 Technical Requirements multistandard base stations (UMTS/ HSPA +/ LTE) ............................................ 174 Technical requirements of the Radio Network Controller (RNC) ................................................................ 176 Technical characteristics of the packet core.................................................................................................. 178 Technical characteristics of interfaces .......................................................................................................... 179 Core Specifications SAE / LTE .................................................................................................................... 180 MME techniques features ............................................................................................................................. 180 Technical specifications of SAE Gateway .................................................................................................... 181 Technical management of the system ....................................................................................................... 183

Network Equipment ...................................................................................................................................... 198 User terminals ............................................................................................................................................... 206 Expectations and needs of end users ............................................................................................................. 213 New services can be provided with LTE ...................................................................................................... 214 The LTE Ecosystem ..................................................................................................................................... 218 For TeliaSonera ............................................................................................................................................ 220

8.5 Conclusions ..................................................................................................................................... 222 ACRONYMS .............................................................................................................................................. 225

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LTE Fundamentals

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Evolution and trends of Mobile Telephony

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1.1

Introduction

Traditionally, broadband service has been provided by means of fixed access technologies because they offer greater accessibility, in comparison with mobile access technologies. Following this, in recent years, telecom operators have boosted the deployment of wireless telecommunications networks, due to the possibility that the end user to use higher-capacity systems, while allowing flexibility in terms of mobility. Because of this, research groups around the world have and are devising new standards for wireless access in order to implement systems that offer greater capacity for bandwidth in the access, and that in turn make efficient use of the spectrum. For this reason, mobile phone networks have evolved to provide higher bandwidth using technologies such as HSPA + and LTE. The latter emerges as an initiative of the 3GPP, in order to meet new technological needs that today's end users are demanding. This envisages the delivery of new voice and data applications, as well as improved speed of access to information. Also, LTE grows on a scalable flat network design, which seeks to improve the services offered by second generation networks and existing third-generation. Among other things, the evolution of mobile systems have meant that today there are standard technology solutions for the benefit of operators and manufacturers. The first mobile communication systems (analog systems) were different for each country, so that economies of scale were achieved worldwide. However, after the introduction of Global System for Communications (GSM, Global System for Mobile Communications) begins to speak of a single common solution worldwide in regard to mobile telephony. Despite its success, factors such as lack of services and the need for new connectivity solutions have led to the study and development of new mobile technologies Third and Fourth Generation. Because of this, this chapter outlines the technological and market reasons that justify the emergence of new mobile technologies.

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1.2

Importance of mobility in telecommunications

The possibility that a user can communicate at any time and from anywhere using a single device, has always been one of the main challenges facing the telecommunications system. As part of the mobility in question, the mobile phone user must have the following facilities: 1. Roaming: Allows a user to access the different telecommunications services from any country that is, if there are prior agreements between the operator who is subscribed and existing operators in different countries around the world. Usually, for you may enjoy this feature, you must (apart from subscribing to the service) have mobile terminals, allowing them to enjoy their voice and data services contract to move to other countries. 2. Handover or transfer: The process that allows users to carry a mobile terminal to maintain the connection and voice and data sessions, when they move between different areas of coverage. Based on the above, then discussed the trend toward mobile phone technology, for which demand will respond to the needs of mobility, ubiquity and new services

1.3

Increased demand for mobile data services

The evolution of mobile communications networks, rather than by technological necessity, is caused by the need to provide new telecommunications services. Using the concept of service, have adopted new technologies and changing the approach to providing basic voice services, to a model where the telecommunications operator looking to offer new data services, with the aim of improving the user experience, and increased revenues. Besides this, it seeks to enrich the ubiquitous mobile feature that allows end users to access broadband and a portfolio of related services from their mobile device at anytime, anywhere. Thus messaging services like MMS, SMS and new services such as instant messaging, electronic commerce, and social networks are contributing significantly to the income received by the telecommunications operators.

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1.3.1

Evolution of mobile terminals to the increased demand for data

Today's mobile devices or terminals are becoming crucial to meet the communication needs of individuals. Aware of this, in recent years, handset manufacturers and telecom operators have felt the need to adapt the devices to access the lifestyle of people, providing a tool for them to have access to a diverse set of new services and applications. Because of this, the mobile phone remains the main device of choice as well as allowing voice communication, is becoming an important means for the user can access entertainment services (example games and television), news and advertising. In turn, being used as an ideal tool for starting content, such as, audio / video and photographs, as well as to interact through social networks, which also allow the creation, distribution and consumption of content.

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Today, in the market it can be found terminals with basic services like voice and sending text messaging to more advanced terminals (type Smartphone) which have a wide range of data services and in turn are characterized by smaller, lighter and aesthetically adopted by many users. It should be noted also that a factor in the expansion of mobile services, will be the price of the terminals. For this reason, today, many telecom operators, in addition to its range of services, are subsidizing the cost of 3G handsets as an incentive to motivate its users to use new applications and services offered today in the market, which in turn will help drive growth in mobile subscribers in the future. This excessive increase that may arise should be complemented with more robust networks, namely higher capacity, both during transport and access.

1.3.2

The phenomenon of Smartphone

As mentioned earlier, one of the fastest growing devices is the Smartphone. It is estimated that smart phones will occupy 24.2% of the market for 2011, and this number is expected to exceed 30% by 2012. In turn, as part of the e statistics support this trend, the Kelsey Group and findings made a consumer survey of users of U.S. mobile phones and reported that 18.9% of mobile consumers now use a Smartphone. Currently there are several types of smart phones such as RIM Blackberry, the Nokia E61, the 6650, the HTC G1, the Sony Ericsson Xperia X1, the LG Incite, the HTC FUZE, Apple iPhone and Palm Treo.

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1.4

Evolution of communications to mobile broadband

Today's users demand higher speeds and quality of access to telecommunications services and new value-added services, which require higher bandwidth for proper performance. For this reason, the pursuit of meeting the needs of consumers, based on the need for high capacity Internet access from their mobile devices (known as mobile broadband), is one of the main reasons motivating the development. As in Figure 1 an estimate on the number of broadband subscribers around the world will be about 3400 million in 2014. For this year it is estimated that about 80% of these consumers use mobile broadband.

Figure 1 - Estimated global growth of broadband subscribers

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1.4.1

NGN as a principle to evolve towards broadband

Access networks are a key element because of its influence on the supply and quality of services. Today in particular, networks of broadband access play an important role in the development and provision of new services supported on Internet. As part of the need for users to enjoy higher bandwidth, born the concept of Next Generation Networks (NGN New Generation Network) which defines the evolution of telecommunications networks in the future. NGNs are based on Internet protocol (IP, Internet Protocol) that allow the delivery of services through the use of multiple access technologies, able to guarantee quality of service, and in which servicerelated functions are independent of the underlying technologies associated with transport. Two of the elements that characterize the NGN are the end-to-end IP connectivity and separation of the service platforms of the network infrastructure. Figure 2 shows architecture similar to what in reality would be a next generation network.

Figure 2 - General diagram of a next generation network (NGN)

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The demand for higher bandwidth requires the transformation of both backbone networks and in terms of access, the latter being the one that requires greater investment and effort from those involved. It uses the concept of Next Generation Access (NGA, New Generation Access) to define the deployment of NGN access networks. For the foregoing reasons, it is estimated that in the future all the networks evolve towards an NGN architecture model and the demand for higher bandwidth will drive the deployment of new access technologies. And is also important to note that the relevant element is not so much the technology or the type of network deployment, but the services and bandwidth that may be provided by the evolution of existing networks. Despite this, LTE is a technology that today is seeking to be implemented by several operators around the world due to the capabilities in terms of new services and applications that technology offers.

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1.5

Evolution generation mobile networks

The evolution of mobile telephony has been marked by several generations. Each of them has special characteristics that differ markedly from one another. Between the late 70s and early 80s, appears the first generation (1G), which was characterized as analog type. The same, using the technique called Access: Access Frequency Division Multiple (FDMA, Frequency Division Multiple Access). Given its limited bandwidth, the services were voice-only 1G. Moreover, given the limited number of channels were blocked calls regularly. In turn, the unavailability of the network and offering little security were the main complaints from users. In the 90s, the cell phone industry has evolved into a second generation (2G).This was characterized as the digital type, appearing also new services such as Caller ID, Three Way Calling, low data transfer speed as well as sending short messages (SMS, Short Message Service).The second generation evolved from TDMA / GSM to GPRS, EDGE (Enhanced Data Rates for GSM Evolution). In Europe, for example, adopted the TDMA-based 2G technology known as GSM (Global System for Mobile Communications), which was implemented in many other countries around the world. Subsequently, new services and applications, were sued by the users, prompted him to give rise to third generation (3G). Using the mobile technology Wireless for third generation known as Wideband Code Division Multiple Access (WCDMA), which increases data transmission rates of the systems GSM using interface CDMA air instead of TDMA and therefore provides data rates much higher on mobile and portable wireless devices than are offered by GSM for example. As an initial improvement in the standard evolution and 3G / UMTS, joined the technology known as High Speed Packet Access (HSPA). HSPA is continually evolving thanks to the work of standardization 3GPP consortium, which regularly publishes Releases, updated technical specifications that improve the standard. This evolutionary improvement is commonly known as 3.5G and is considered the first step before the fourth generation (4G).

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1.6

Towards the Fourth Generation (4G)

Today, as we think about the next step in evolution of mobile telecommunications, which is known as fourth-generation networks (4G). Its development is directed to a mobile network based entirely on IP, allowing the user to have higher access speeds and a greater convergence of technologies. This means, that this generation is designed to provide end users the possibility to enjoy a wireless connection anywhere, anytime, with speeds of access to information much higher than those offered by previous generations. In this regard, ITU-R (corresponding to the radio division of the ITU) drafted a document known as 4G/IMT, which establishes minimum requirements for mobile access technologies must meet to be called 4G. The following summarizes the key points of the document 4G/IMT defined for the fourth generation: • Create a network to enable interoperability between different wireless communication standards. This indicates that it will support various access technologies, which will integrate seamlessly into a network layer based on IP protocol. This means that the network must use only packet switching, which is required for IPv6 is deployed instead of the IPv4 standard currently in use. • Using an access system that makes efficient use of spectrum. This will require use base band modulation technologies such as OFDM (Orthogonal Frequency Division Multiplexing), allowing the orthogonality of the carriers, which is a multicarrier modulation scheme highly efficient. • Another technique to use is accessible MIMO (Multiple-Input and MultipleOutput), which is a radio technology that uses a multi-antenna system on the side of the transmitter and receiver. Because of the multiple antennas, the spatial dimension can be exploited to improve the performance of the wireless link, making the signal stronger, more reliable and helps increase the speed of access provided to end users. • In turn, 4G networks must meet high quality of service and security end to end, and able to offer any service at any time, anywhere. This means you must provide transparency in access to services, regardless of the access network the user to use. • As one of the requirements that have been established, is to offer access speeds of 100 Mbps and 1 Gbps, in outdoor environments (mobile) and internal (fixed), respectively, which represents a high target to be achieved by technology mobile.

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Figure 3 shows an overview of the process that has marked the evolution of mobile telephony into the fourth generation:

Figure 3 - Evolution of mobile access technologies

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The table on the next figure describes and compares the different generations of mobile systems mentioned above:

Comparison between mobile telecommunications networks

Generation mobile telephony

1st generation (1G)

2nd Generation (2G)

3rd generation (3G)

4th generation (4G)

Use life

1970's-1980's

1990's-2020

2001 to date

In 2010 begins with LTE

NMT, AMPS ...

GSM, D-AMPS, PDC ...

IMT-2000 (UMTS, CDMA2000)

IMT-Advanced (LTE)

Standards

Owners Standards

Closed standards

Open Standards

Integrating different standards

Bandwidth used (Theoretical)

Used 30 KHz AMPS

Using D-AMPS uses 30 KHz and 200 KHz GSM

Using 5 MHz WCDMA Speeds up to 2 Mbps

Scalable band widths. Speeds up to 1Gbps.

System used

Analog / Digital

Analog

Digital

Digital

Digital

Packet Switched (PS) / circuit switching (CS)

CS

CS

CS and PS

PS ("All IP")

Roaming

National

International

Global (With same technology)

Global (Other technologies)

Services

Voice

Voice and data (SMS, MMS, internet narrow band)

Voice and data (SMS, MMS, internet broadband)

IP Multiservice

Figure 4 - Comparison between mobile telecommunications networks

1.6.1

Fourth Generation Technologies

The Radio communication Sector (ITU-R) officially defined the Fourth Generation wireless systems (4G) called IMT-Advanced. 3GPP addressed the requirements of IMT-Advanced version of LTE (Release 10), called LTE-Advanced. Other technologies such as mobile WiMAX (Mobile WiMAX, Mobile Worldwide Interoperability for Microwave Access), specified in the IEEE 802.16m, and ultra mobile ultra-wideband (3GPP2 UMB, Ultra Mobile Broadband) are presented as candidates for 4G. Of these three, mobile WiMAX and LTE are aimed to be the dominant standards that give the initial basis for this emerging generation telecommunications technology in the fourth generation.

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1.7

Global demand for mobile access

Currently GSM is positioned as the technology most widely deployed worldwide, representing more than eighty percent of mobile phone subscriptions. The following figure shows the breakdown in terms of number of subscribers existing technology.

Worldwide subscriptions by technology (December 2009)

Technology

Subscribers (thousands)

GSM

3.449.011,00

WCDMA

255.773,00

Relative share

80.06%

5.94% WCDMA / HSDPA

132.079,00 3.07%

TDMA

753,00 0.02%

TD-SCDMA

825,00 0.02%

CDMA 2000 1X

309.508,00 7.18%

CDMA 2000 1X EV-DO

121.822,00 2.83%

CDMA 2000 1X EV-DO REV A

13.912,00

PDC

2.752,00

iDEN

21.362,00

0.32% 0.06%

0.50% 4 307 797,00

Figure 5 - Comparison between mobile telecommunications networks

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To see a bigger picture, the organization 3G Americas unites telecommunications operators and vendors are located throughout the Americas, published a study estimating the number of global mobile subscriptions. The following figure shows the behavior of global demand for distributed mobile technology:

Global volume of subscribers by technology (million) YEAR:

TECHNOLOGY

UMTS-HSPA GSM CDMA WIMAX LTE TOTAL

2009

2010

2011

2012

2013

2014

438

649

957

1400

2000

2700

3700

3900

4000

3800

3400

2700 769

459

521

583

645

707

2,80

7,50

16,70

37,10

82,10

0

0

0,50

3,50

13,10

44,50

131,50

4600

5078

5560

5895

6233

6300

Figure 6 - Worldwide subscriptions by technology (Year 2009)

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To complement the information previously shown, Figure 7 display graphically the behavior described in Figure 6.

Subscribers by global wireless technology - 2014) ( 2009 7000

6233

6300

5895 6000 5560 5078 1400 5000

2000

957

4600

2700 649

438

4000

3000 4000

3800

3900

3400

3700

2700

2000 S us criptores ( millones)

1000

459

521

583

2009

2010

2011

707

769

2013

2014

645

0

2012 YEAR

LTE

WIMAX

CDMA

GSM

UMTS -HSPA

Figure 7 - Expected growth in mobile subscribers worldwide

From the information presented above, it is expected that 3G technology is the technology that will take an higher stake on the 2G technology swap. It is further noted that the growth of adoption of LTE technology will begin to gradually increase from the year 2010, taking the year 2014 demand of approximately 131.5 million subscribers.

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For its part, based on the trend presented above, it is estimated that LTE will start to grow significantly in demand since 2015, causing subscribers to gradually abandon legacy technologies such as 2G and 3G. The above is shown in Figure 8.

Figure 8 - LTE demand trend

Despite this trend so strong to move towards LTE, one must remember that mobile WiMAX technology today is also considered as a candidate to evolve into the Fourth Generation, which is why later on this book a brief comparison between technologies will be presented.

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Comparison between WiMAX and LTE

The mobile WiMAX and LTE are emerging as key technologies for the evolution to 4G. The selection of any of these technologies by telecom operators will depend on various factors including the availability of spectrum and their own business strategies.

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2.1

WiMAX Technology Overview

World Interoperability for Microwave Access Worldwide (WiMAX) is a wireless broadband technology. Is designated as the IEEE 802.16 working group IEEE organization specializing in the access point to multipoint broadband using WiMAX technology. This technology is based primarily on the two substandard IEEE 802.16d for fixed access, and 802.16e for mobile access. Presenting two different standards for WiMAX operators has enabled the scalability of their networks according to different requirements to support last-mile services. Fixed WiMAX is particularly interesting in providing last-mile access to rural areas without access to wired network infrastructure or other wireless infrastructure. Primarily focuses on residential-type users without access to broadband services, located in remote areas where it has so far been too expensive to access by traditional broadband infrastructure. Subsequently, given the need for users to maintain these services in mobile environment, there is the standard known as IEEE 802.16m WiMAX version 2.0 or Mobile WiMAX. This standard is an enhanced version of IEEE 802.16e standard and has been proposed as a fourth-generation technology.

2.2

LTE Overview

As part of the standards that want to implement for the Fourth Generation, appears LTE preliminary proposal, on which there has been significant investment in research and development by stakeholders in the telecommunications industry as will be shown forward. However, to meet the requirements established by the ITU 4G, the highest governing body for telecommunications in the world, the Group 3GPP (3rd Generation Partnership Group) has been given the task of setting a new radio access technology that has called LTE.

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This has been done with the aim of working on the development and improvement of the communication standard Third Generation WCDMA based UMTS system. This path of evolution, born since the 3GPP, in late 1999, developed the first version of WCDMA. By way of overview, the main versions or Releases that mark the evolutionary path listed below: • Release 99: first version of WCDMA developed in late 1999 and was part of IMT-2000 standards. • Release 5: This version developed in 2002, introduced speed improvements in communications from the network to the user (downlink) creating the data access protocol called HSDPA. • Release 6: This version completed in late 2004, introduced speed improvements in communications from the user to the network (uplink) creating the data access protocol called HSUPA. • Releases 7 to 10: versions are generally looking for in the stage of access of a mobile network have higher bandwidth, lower latency and higher capacity to meet demand in urban areas. In Release 7 defines the protocol HSPA +.The Release’s 8 and 9 correspond to the LTE standard and Version 10 is the standard LTE-Advanced, which, unlike LTE, if it is accepted as standard Fourth Generation.

2.3

LTE-Advanced for IMT-Advanced

Parallel to the work on LTE and future enhancements in Release 9, the 3GPP is working on creating specifications that qualify in the process of IMT-Advanced in ITUR. ITU-R is developing a framework for next generation wireless networks. The following are the requirements that the ITU-R has been defined for IMT-Advanced. • Support for speeds up to 1 Gbps in low mobility scenarios (nomad) and 100 Mbps for high mobility. • Support for large bandwidths. • Minimum requirements for spectral efficiency in different operating scenarios. Besides the above, the 3GPP has an own set of requirements among which is backwards compatibility with LTE (Release 8). This requirement is set so that a device can access a network LTE LTE-Advanced (Release 10) and similarly a device to LTE-Advanced LTE access network, in addition to any network or device that

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meets specifications Release 9. For its part is also due to mobility between LTEAdvanced and other radio access technologies such as GSM / EDGE, WCDMA and CDMA2000. Ie, LTE Advanced is HSPA + and LTE, HSUPA, HSDPA is a UMTS, ie they are extensions but do not cause incompatibility. It is expected that the specifications of ITU-R was completed in early 2011, which requires 3GPP prepare its first set of specifications for the end of 2010. Among the improvements are under investigation and is expected to be part of these specifications are: • It is hoped to extend coverage by allowing the user equipment further away from a base station, send your information via relay nodes for better communication. • Scalable bandwidth up to potentially around 100 MHz: It is expected that this capacity is reached mainly based on the solutions that are expected to be deployed in LTE, although not yet defined as to undertake this expansion. • Network mobility solutions and nomad / local area. • Flexible use of spectrum. • Configuration and network operating independently (Self Organizing Network). • Coordinated multipoint transmission and reception that relates to the use of MIMO transmissions coordinated by different transmitters.

Although all the above items are under study, does not necessarily mean that they will be included in the specifications of 3GPP Release 10. It may be that the decision to include some aspects within the Release 9 and can also reach the conclusion that its complexity is too high or the benefits are few to be considered within the specifications for LTE-Advanced. It is hoped that this research is completed by the end of 2010 in preparation for the start of the specification to be included in Release 10. It is noteworthy that LTE will not only be evaluated by the ITU-R for IMT-Advanced process, but so will other radio access technologies and if they meet the minimum requirements will become part of the family of IMT -Advanced.

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The following figure presents the most important dates in the process of specification of LTE-Advanced. You can see that this proposal is already in an advanced stage and is expected to be completed no later than 2011.

Important Dates specification of LTE - Advanced

Progress made

Review article on LTE - Advanced adopted by 3GPP

Requirements for LTE - Advanced (TR 36913) approved by 3GPP

Prior submission of LTE - Advanced made to ITU-R

Preview LTE - Advanced made to ITU-R

Final presentation of LTE - Advanced made to ITU-R

Completion of Advanced LTE specifications made by the 3GPP

Response

March 2008

June 2008

September 2008

June 2009

October 2009

2010 -2011

Figure 9 - LTE specification schedule - Advanced

Moreover, given that the standard LTE-Advanced is not yet finalized and because today, as indicated below, some operators are considering the benefits of deploying LTE networks, then performing a comparison between the LTE and mobile WiMAX standard, proposed as evolutionary paths to the Fourth Generation.

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2.4

Technical comparison between LTE and Mobile WiMAX

Some of the key features that define the two technologies are presented in the next figure.

Comparison between LTE and Mobile WiMAX Feature

Mobile WiMAX

3GPP-LTE

Core Network

All IP Network

All IP Network

Access Technology. Downlink (DL)

OFDMA

OFDMA

Uplink (UL)

OFDMA

SC-FDMA

Frequency band

2.3-2.4GHz ,2.496-2 0.67 GHz, 3.3-3.8 GHz

70,850,1800,2100,2500 MHz frequency bands

DL

75 Mbps

100Mbps

UL

25Mbps

50Mbps

Bandwidth of the channel

5, 8.75, 10MHz

1.25-20MHz

Cell Radio

2-7km

5km

100-200 users

> 200 users to 5MHz

Bit rate:

Cell Capacity > 400 users for higher bandwidth Spectral efficiency

3.75 (bps / Hz)

5 (bps / Hz)

Handover

Hard Handover

Soft handovers

DL

2Tx * 2RX

4Tx * 4RX

UL

1Tx * NRX

2Tx * 2RX

MIMO:

Figure 10 - Comparison between LTE and mobile WiMAX

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Based on the above, are the following similarities: • Mobile version of WiMAX will reach performance capabilities similar to LTE, and both take advantage of multi antenna techniques (MIMO), which dramatically improves the communication channels that will achieve better data transmission rates. • Both WiMAX and LTE benefit from IP architecture that simplifies data transmission, since it is optimized for that protocol. • The most important similarity between LTE and WiMAX OFDM is the substantially improvement in the use of radio spectrum. Despite these similarities, LTE appears to offer better performance because it offers faster speeds and enhanced capabilities for cell about Wimax technology. LTE also provides greater spectral efficiency, allowing you to make better use of radio spectrum, a factor which is of utmost importance when choosing an access technology.

2.5

Interoperability between the two technologies

There is an aspect that suggests that LTE is supplemented in some areas with networks WIMAX . This is because there are remote places where there is no 2G and 3G coverage, but there WIMAX coverage plans. Anticipating such a scenario of convergence, able to make a user can access mobile broadband services using the same terminal, some manufacturers have focused their efforts on the manufacture of electronic devices that can operate both technologies, such is the case of chip maker Beceem who announced the first chip called BCS500, which combines LTE and WiMAX. This is how this chip supports WiMAX 16e standards and 16m and LTE Release 8 download capabilities allowing up to 150 Mbps perform handover between the two technologies. Beceem expects the chip is ready to be marketed in the second quarter of 2011. The actual technical aspect of the way it carries out the interconnectivity between WiMAX and LTE, will be discussed in Section 5.11 of this job.

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2.6

Tendency for operators to implement LTE

Currently WiMAX has an advantage in their favor on LTE, this advantage is the anticipation that WiMAX was created with respect to LTE. This means that by the time the new LTE networks are deployed, consolidated WiMAX networks already exist in many markets around the world. Despite this, WiMAX technology has not been as successful as hoped in the beginning and the prevision is that LTE will surpass WIMAX in 2012. For example, although since 2007 were initiated implementations of Wimax technology, three years after the operator TeliaSonera has deployed, the first commercial networks with LTE technology in the countries of Sweden and Norway. This is the first step could lose the momentum operators to deploy WiMAX, a situation well known manufacturers and operators, so that they are in a stage of analysis to define future technology and initiate deployment their networks as quickly as possible. Today, some of the biggest in the market as Nokia and Motorola have turned to the development of LTE without even thinking about a side project with WiMAX technology. In addition operators like AT & T, like T-Mobile and Verizon Wireless have opted for the adoption of LTE and plan to carry out large deployments with this technology. Another reason why many have decided on LTE is the aspect of compatibility with legacy networks. For its part, the compatibility issues that have arisen between the various versions of IEEE 802.16 put many operators to reflect on the true capacity of these systems in terms of their support back. LTE implies an evolution of the 3GPP legacy systems, so you will live in the same network simultaneously 2G and 3G technologies, and future 4G LTE-Advanced. But beyond seeing both as competing technologies, we can conclude that in reality there is no rivalry. Today it is envisioned that both WiMAX and LTE will become real technology fourth generation wireless. Still, if we consider that the vast majority of operators who currently have 2G and 3G networks have decided to LTE, will spend a few years to produce real growth and maturity of the LTE technology throughout the world.

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3

Third-generation networks as the basis for the evolution to LTE

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3.1

Evolution of a UMTS network to LTE

The third generation UMTS system based on access technology W-CDMA has been developed in many parts of the world. To ensure that this system has to remain competitive future, in November 2004 3GPP started a project to define a long-term evolution of the cellular system called UMTS. Its main focus is to improve or evolve the UTRAN network to LTE. The specifications related to this effort is formally known as Access Evolved UMTS Terrestrial Radio (E-UTRA, Evolved UMTS Terrestrial Radio Access) and Enhanced Terrestrial Radio Access UMTS evolved (E-UTRAN, Evolved UMTS Terrestrial Radio Access Network) but are commonly referred to as the LTE project. This first version of LTE is documented in the specifications of 3GPP Release 8. A side project called Evolution of System Architecture (SAE, System Architecture Evolution) defines an all-IP architecture composed of a core packet switching network called evolved packet core (EPC Evolved Packet Core). The SAE network architecture is an evolution of the core network and has the following characteristics: • Simplified architecture directed towards all-IP network. • Support for multiple systems such as GPRS. • Mobility between different radio access networks.

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The combination of EPC and define E-UTRAN evolved packet system (EPS, Evolved Packet System). In this way the whole system is called the LTE / SAE or simply LTE. When LTE solution for the 3GPP standard, is proposed as a future scenario, the interoperability of this technology with existing networks 3G/WCDMA 2G/GSM is garanteed. For the foregoing reasons, the following is an overview of the number of thirdgeneration networks, specifically UMTS type, in order to know its architecture and its basic features, which serve as reference for further understanding and proposing a series of general recommendations on a technical level, to move towards LTE from these mobile networks. It is recalled that a telecommunications network 2G and 3G, is composed of three main elements: a core network (CN, Core Network), a Radio Access Network (RAN, Radio Access Network) and equipment (UE, User Equipment).

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3.2

3.2.1

UMTS Network Structure

UTRAN

The group designed specifically for UMTS 3GPP access network called Terrestrial Radio Access Network UMTS (UTRAN, Terrestrial UMTS Radio Access Network), which is described below. This network is composed of Radio Network Controllers (RNC, Radio Network Controller) and base stations known as Node B, together make up a Radio Network Subsystem (RNS Radio Network Subsystem).

Figure 11 - Radio Access Network UMTS.

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The following is a brief description of the elements of the UTRAN: • RNC: controls one or more nodes B. The interface between different RNC is a logical interface, so there is not necessarily a direct physical connection between them. The RNC is comparable to the base station controller (BSC, Base Station Controller) in GSM networks. • Node B: Node is the liaison between the RNC and the mobile terminals. Contains the physical layer radio interface so that performs the functions of modulation and demodulation, error detection, time synchronization and frequency, among others. Given that there should be interoperability between the networks of 2G and 3G access, it is important to mention that GSM access network consists of Base Station Subsystem (BSS, Base Station Subsystem). Each subsystem consists of a Base Station Controller (BSC, Base Station Controller) and one or more base transceiver stations (BTS, Base Transceiver Station). The BSC controls the functionality of the BTS with an air interface (A-bis). The following is a brief description of the elements of the BSS: • BSC, in charge of the functions of radio resource management, power control and handovers between cells, among others. • BTS: consists of one or more transceivers (TRX). BTS can be omni type with one cell or sectorized with multiple cells, typically three.

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Interface -

Abis

BSS

-

Interface -

A

- A

Abis

BSS

Figure 12 - Radio Access Network GSM

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The next figure shows the UMTS network architecture coexisting with a GSM access network.

Abis B

Um

G

BSS E A B Gb

Iub Cu

Uu

PSTN

PSTN

D

C

IuCS H Gs

USIM

F

IuPS Gf

Gr

Gc

IuCS Gn

RNS

Gl

IuPS Iub

RNS

Figure 13 - UMTS network architecture coexisting with GSM

It is noteworthy that the interface "Uu" between the UE and UTRAN, and the interface "Iu" between UTRAN and core network (CN, Core Network), are open-standard interfaces, allowing you to connect terminals and equipment provided different manufacturers.

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3.2.2

Core network

The core network is divided into two domains: the domain of packet switching and circuit switching. The circuit switched domain provides the main element Switching Center Mobile Services (MSC, Mobile Switching Center), while the packet domain covers the main elements of the Service Support Node GPRS (SGSN, Serving GPRS Support Node) Node Server and Service Support GPRS (SGSN). The following describes these and other elements that make up the core network: • Switching Center Mobile Services (MSC) is the central element of the Core Circuit Switched (CS-CN, Circuit Switching Core Network). The MSC of the GSM network to 3G can be used that allows updates to comply with the requirements of 3G. This element is connected to access networks of GSM and UMTS, with the Public Switched Telephone Network (PSTN, Public Switched Telephone Network), as well as with other MSC, SGSN and the various registers of the core of the network (HLR, EIR), among others. • Visitor Location Register (VLR, Visitor Location Register): This is a temporary database that contains all information from users who are present at any given time in the location area controlled by the VLR. Overall MSC and VLR are physically combined. Among its main features are, allow authentication of the mobile and also connects to other VLR and HLR through the network signaling system. • Local Location Register (HLR, Home Location Register) contains a permanent record of subscriber data. While the records are temporary VLR in the HLR are permanent, although they handle almost the same information. • Equipment Identification Register (EIR, Equipment Identify Register): Stores Identities international Mobile Station Equipment (IMEI, International Mobile Equipment Identities). Usually contains three lists to indicate the status of equipment: IMEI of computers that are authorized to operate normally (white list), stolen equipment and therefore are prevented from connecting to the network (black list) and finally the gray list are registered with any equipment malfunctions occur. • Authentication Center (AuC, Authentication Center) is associated with the HLR. Authentication keys stored subscriber and International Mobile Subscriber Identity (IMSI). • Gateway MSC (GMSC, Gateway MSC) is an MSC that is located between the PSTN and other MSC located on the network. Its function is to achieve routing incoming calls to the appropriate MSC.

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• Server Node Service Support GPRS (SGSN) is the principal element in the packet switching network, which contains subscription information and user location. • Support Node Gateway GPRS (GGSN, Gateway GPRS Support Node): Makes the interface between the packet core with external data networks, such as the Internet. The 3GPP Release 5 brings significant changes to the core architecture of the network. The next figure shows the network architecture, Release 5:

Figure 14 - 3GPP Release 5 architecture

In this new architecture incorporates a control architecture known as IMS. At the same time as bringing new elements such as Base subscriber server (HSS, Home Subscriber Server), which functions as an HLR evolved, and is also the element of connection between IMS and the packet switched domain. For its part, this new architecture the MSC is divided into two entities, the media gateway (MGW) and a MSC server. The control logic is performed by the MSC, while the switching is done MGW. This separation allows the network to make use of more efficient routes for the transmission of high-speed data, while control messages may follow other routes.

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For his part, Release 5 incorporates an all-IP network, which means that all traffic, including voice, is carried as IP packets. The next figure shows the IMS architecture:

Figure 15 - Architecture of the IMS domain

In the domain of IMS data traffic is transported through SGSN and GGSN. For his part, HSS combines and performs the functions that make the HLR and AuC. On the other hand comes a function element called Call Session Control (CSCF Call Session Control Function), which is the central element in IMS. There are three types of CSCF: • Servant CSCF (S-CSCF): Provides the session control services for the computer terminal. These include the decision of routing and session establishment, maintenance and release of multimedia sessions. It also generates information charges for the billing system; • Proxy CSCF (P-CSCF) is the first entity of IMS is contacted by the user's computer when you log into the network. The P-CSCF passes the control of the session towards the S-CSCF located in the home network;

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• Interrogating CSCF (I-CSCF) is the point of contact within the operator's network for all connections destined for that network subscribers or subscribers are roaming. Finally, other elements within the domain of IMS are: • Disengage Control Function in Gateway (BGCF, Breakout Gateway Control Function): selects the network in which the domain interoperability and circuitswitched PSTN is going to happen. If given in the same network BGCF select a MGCF responsible for such interoperability. If another network with BGCF redirects the session signaling to another BGCF in the net. • Function Control Media Gateway (MGCF, Media Gateway Control Function) is an entity that is responsible for interoperability. Perform conversion of protocols between the PSTN and IMS protocols call. • Processor Media Resource Function (MRFP, Multimedia Resource Function Processor): handles the bearer channels and can handle different flows of information. • Controller Media Resource Function (MRFC, Multimedia Resource Function Controller) controls the flow of information resources in the MRFP, a task accomplished by interpreting information that comes from application servers, S-CSCF and the MRFP. • Media Gateway Intermediate (IM-MGW, Intermediate Media Gateway): terminates bearer channels from a circuit network and information flows in a packet network. MGFC interacts with resource control, in addition to owning and managing other resources such as echo cancellers. • Subscriber Locator Function (SLF Subscription Locator Function): it is only necessary when there are plenty of HSS bodies on a network. • Application Server (AS, Application Server) offers value-added services and can reside either on the local network or in a third location.

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4

Standardization and technical requirements according to 3GPP LTE

Based on the above shown in the following chapter provides the key technical requirements and standardization proposed to move towards LTE.

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4.1

Reason for the evolution of the system architecture

The target for the development of system architecture to improve aspects such as speed of access and transport as well as quality of service, using this a fully converged network based on packet switching and ability to support mobility and service continuity between heterogeneous access networks. According to the technical report TR 23.882 were identified a number of high-level requirements for an architecture based on SAE, among which we highlight a few: • Must support 3GPP and non 3GPP systems. • You must provide a scalable architecture without compromising the ability of the system, separating the control plane and transport plane. • Must be based on IP connectivity with improved quality of service. • Mobility with other systems and even non-3GPP. 3GPP must support real time applications as well as applications and services that are not real time. • Should enable interoperability between terminals, servers and systems with IPv4 and IPv6 connectivity. • You must ensure at least the same level of security of Subscriber which is in the current 3GPP networks. • Must support the IP Multimedia Subsystem (IMS, IP Multimedia Subsystem) as well as systems in the domain of circuit switching.

4.2

Working groups and the definition of technical specifications for LTE

The work focused on the decision of the radio technology as well as the system architecture. It concluded that needed something new and not just an extension of the WCDMA system as a result of a complex set of requirements to cover different bandwidths and a certain amount of data transfer rates. Within 3GPP Technical Specification Group of the Radio Access Network (3GPP TSG RAN, 3GPP Technical Specification Group Radio Access Network) is responsible for the development of LTE specifications for what is the access network. This job specification is covered by the various working groups (WG, Working

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Groups) which are listed under each group of technical specifications (TSG, Technical Specifications Group). This distribution is shown in the next figure.

Figure 16 - Work structure of the 3GPP

As part of the main specifications for the access network, it was decided to use technology Multiple Access Orthogonal Frequency Division (OFDMA, Orthogonal Frequency Division Multiple Access) as technology in the downlink. To access uplink technology was chosen Division Multiple Access Single Carrier Frequency (SCFDMA Single Carrier Frequency Division Multiple Access) as the most favorable, a decision that was supported by manufacturers and operators in general. A significant improvement over WCDMA is the technology that both Frequency Division Duplexing (FDD, Frequency Division Duplexing) such as Time Division Duplexing (TDD, Time Division Duplexing) have the same solution for multiple access, ie that an adjustment is made to minimize the differences in their modes of operation. This decision by the multiple access was made official in 2005 and after that the work was focused on the technologies chosen for LTE. Also, it was decided that it should have a radio access network (RAN, Radio Access Network) of a single node, which is achieved by putting all the functionality of the radio base station (Node B). The name of this new element is eNodeB, representing the letter "e", evolved. The main difference in relation to this aspect is that it removes the element RNC delegating its functions to the eNodeBs. The specifications for the evolved packet core (EPC Evolved Packet Core) are covered by the technical specification group core network and terminals (TSG CT, Technical Specification Group Core and Terminals) and also by the group of

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technical specifications services and systems (TSG SA, Technical Specification Group Services and System Aspects). The group of technical specifications of the radio access network GSM / EDGE (GERAN TSG, Technical Specification Group GSM / EDGE Radio Access Network) is responsible for changes in GSM / EDGE introduced in Release 8 to facilitate interoperability between LTE and GERAN. For its part the group of technical specifications of the radio access network WCDMA (TSG RAN, Technical Specification Group Radio Access Network) is responsible for the changes introduced in WCDMA Release 8 to facilitate interoperability between LTE and WCDMA.

4.3

3GPP requirements for LTE

In November 2004, began work related to the evolution of the access network known as UTRAN. In this work were present operators, manufacturers and research institutes with a large number of proposals and views. Then, in early 2005 began work on the specification of 3GPP LTE, which published its technical report TR 25.913, Requirements for Evolved UTRA (E-UTRA) and Evolved UTRAN (E-UTRAN). After that recent versions have been published with improvements and fixes, version 9.0.0 being the last one. Key elements of this technical report are described below.

4.3.1

Requirements related to the ability

• Data transfer rates: E-UTRA should support significant increases in data transfer rates, which must be consistent with the spectrum allocation and terminal configuration. For example, a terminal to be able to support maximum speeds of 100 Mbps in the downlink (DL, downlink) and 50 Mbps in the uplink (UL, uplink), each with an allocation of 20 MHz spectrum. • Latency: In the control plane must have a latency equal to or less than 50 milliseconds (ms) between active and inactive states. For the user plane must have a latency no greater than 5ms for a one-way transmission from the transmitted packet is available at the IP layer at the edge of the border UE / RAN until it becomes available in the IP layer the other border RAN / EU. However, this latter requirement should be revised, mainly because you need to specify clearly the terms of latency for this case.

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4.3.2

Requirements related to performance

• Transfer Rate: Transfer rate (throughput) in the downlink (DL) should be for the average user, 3 to 4 times compared to the specifications assigned to HSDPA Release 6, using more than two transmission antennas in the base station and two receive antennas in the terminal device. Besides the transfer fee should be scalable in line with the allocation of spectrum. For the uplink (UL) should have a transfer rate per user on average 2 to 3 times as specified in Release 6, in this case using a transmitting antenna in the terminal and two receiving antennas at the base station. It should get a higher data rate using multiple transmit antennas in the terminal device. • Spectral Efficiency: Spectral efficiency (bps / Hz / site) in the downlink (DL) should be 3 to 4 times that obtained with a system based on Release 6 HSDPA, using two transmission antennas in the base station and two reception terminal. In the uplink (UL) should be 2 to 3 times Release 6 HSDPA obtained and E-UTRA using a transmitting antenna in the terminal and two reception at the base station. • Mobility: Must be optimal for the user transfer rates in the range of 0 km / h 15 km / h. For speeds of 15 km / h and 120 km / h mobility must be supported with high performance. For its part, the mobility across the cellular network must be maintained at speeds of 120 km / h 350 km / h, or 500 km / h depending on the frequency band used (An example of this scenario would be within high speed train). Services real-time voice and supported in the domain of circuit-switched network UTRAN (Release 6) should be borne by the EUTRAN in the packet switched domain to a higher quality or at least equal. • Coverage: coverage up to 5 km in the range of cells must meet the requirements of transfer rate (throughput), spectral efficiency and mobility above. In a range of up to 30 km degradations accepted transfer rates and spectrum efficiency, but must comply fully with the requirements of mobility. For greater ranges requirements have not been defined. • Enhanced MBMS (Multimedia Broadcast and Multicast Service), MBMS service is a feature you are looking for an efficient way to deliver broadcast and multicast services over the network core. E-UTRA should support enhanced modes of UTRA MBMS in comparison with less downtime, provided they are caused by the E-UTRAN network. • Network Synchronization: It is expected that the requirements described in the technical report TR 25.913 are made in the deployment of the network without the use of synchronization between sites.

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4.3.3

Requirements related to network deployment

• Deployment scenarios: There is a wide range of deployment scenarios that can be considered, however at a high level, E-UTRAN should be able to support basically two different scenarios. The first is the deployment of EUTRAN network as an independent network, where the operator deploys the network without the existence of other networks in the area or there are other networks UTRAN / GERAN, or where there is no need for interoperability between them. The second deployment scenario corresponds to a UTRAN network integration and / or networks of GSM EDGE Radio Access (GERAN, GSM EDGE Radio Access Network). In this case the network operator has to totally cover the same geographical area. The deployment and the associated requirements will be defined by demand for mobile services and the environment of competition between operators. • Spectral Flexibility: Must support spectrum allocations of different sizes, which means you should be able to operate in a bandwidth of 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz and 20 MHz for uplink and in the downward. It should also be flexible enough to support transmissions in both directions (DL & UL) making optimal use of available spectrum. • Deployment in the radio spectrum: E-UTRA should be capable of withstanding the following scenarios. o GERAN/3G coexistence with adjacent channel o Coexistence between operators on adjacent channels o Coexisting with spectrum sharing and / or adjacent to the borders of countries o Operating as an independent network, ie without other networks operating in the same geographic area • Coexistence and interoperability with other radio access technologies 3GPP (3GPP RAT Radio Access Technology): Terminals UTRAN LTE will also support and / or GERAN should be able to perform handovers to and from EUTRAN networks. Disruption of services in real time during a handover between E-UTRAN network and a UTRAN should be less than 300 ms and for services that are not in real time should not exceed 500ms. For handovers between E-UTRAN and GERAN should meet the same requirements of time in both cases.

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4.3.4

Requirements for E-UTRAN architecture

E-UTRAN should have a single architecture based on packet switching, not ceasing to be capable of supporting real-time services based on circuit switched domain. It should also support quality of service (QoS, Quality of Service) point to point, taking into consideration the different types of traffic. Finally, the E-UTRAN should be designed so as to minimize delay variations (jitter) for packet TCP / IP.

4.3.5

Requirements for radio resource management

• Improved support for quality of service point to point: E-UTRAN should be able to support improved control over the quality of service, providing a better matching of service requirements, protocols and applications with the resources and network features access. • Efficient transmission of higher layers: You must provide mechanisms for the transmission and operation of higher layer protocols on the radio interface. • Support of load sharing and policy management across different radio access technologies (RAT): This aims to reduce latency and ensure quality of service point to point, when there are different body handovers radio access technologies.

4.3.6

Requirements related to the complexity of the systems

• Complexity of the system in general: Significantly reduce the complexity of the system to stabilize the interoperability in early stages and further reduce costs in terminals and the network itself. • Complexity of terminal: The requirements of E-UTRA and E-UTRAN should be possible to reduce the complexity of terminal equipment in terms of size, weight and battery life among others, always consistent with the advanced network services.

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4.3.7

Protocols and services requirements

The architecture should enable optimization of communication protocols in addition to reducing the cost of future network deployments. On the other hand all the interfaces should be open to ensure interoperability among equipment manufacturers. E-UTRA should efficiently support various types of services such as web browsing, video streaming or voice over IP (VoIP) and more advanced services such as real time video. The VoIP service should be supported with at least the same features as the voice service over UMTS networks based on circuit switching.

4.3.8

Specifications for interoperability with legacy networks

One of the requirements of the new system is to ensure interoperability with 3GPP systems Rel.6, ie SAE expected to coexist with the 3GPP mobile communication networks today. In this way, users can establish a data session in a LTE area where coverage is insufficient, and continuing it in a transparent manner with UMTS, minimizing packet loss and downtime. Another notable design premise of this new architecture is that not only must ensure interoperability with 3GPP legacy systems of second and third generation, but also must provide seamless mobility and continuity of user session between 3GPP accesses and not "3GPP”, such as WiFi or WiMAX. To handle mobility between 3GPP access and non-3GPP has chosen to use mobility skills defined by the IETF (Internet Engineering Task Force), such as Mobile-IP and Proxy Mobile-IP in the SAE GW acts as an anchor point. This involves defining a new interface between the SAE GW S2 and non-3GPP accesses and the requirement that interfaces S5 and S8 (discussed below) support simultaneous GTP protocol (3GPP accesses) and IETF-based protocols (non-3GPP access) depending on the type of access. Therefore, it was proposed an evolution of the architecture according to the 3GPP standard deliveries (next figure).

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Figure 17 - Evolution of 3GPP was a flatter architecture

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4.4

Standardization beyond Release 8

The specification work after the Release 8 has already started, including a series of points that were defined for the Release 8 which was completed in 2009, as well as specifications for LTE-Advanced which is expected to be published in the 3GPP Release 10. Here are the key elements that are being defined in future specifications. • LTE MBMS, which is expected to support the operation with a dedicated MBMS carrier or carrier shared. It can then sends a signal based on OFDMA from different base stations (with the same content) and then be combined in the device. This principle is used for example in digital video broadcasting for personal devices, DVB-H (Digital Video Broadcasting for Handhelds), which is also based on OFDMA. • Improved auto tunable networks (SON, Self Optimizing Networks) whose specification continues in Release 9 • Improved support for LTE VoIP, including the maximum number of users supported simultaneously. • The requirements for base stations operating at different bandwidths and different radio access technologies. The aim is to define the requirements for the same frequency can transmit radio signals eg GSM or LTE and LTE and WCDMA.

4.5

Architecture Overview of LTE / SAE

Evolved System Architecture (SAE, System Architecture Evolution) is the name given to the Fourth Generation Network Evolved proposed by 3GPP for LTE . This advanced network is made up primarily of two main components: • Network Access Evolved Universal Terrestrial (eutrophi, Evolved Universal Terrestrial Radio Access Network) • The Packet Core Network Evolved (EPC, Paquet Evolved Core), also known as evolved packet system (EPS).

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As mentioned above, the idea to E-UTRAN, is that many of the features currently present in the Third Generation Network (3G) to pass the eNode B (known as Node B base stations evolved or developed). That is, the existing RNC would be eliminated. This simplification will mean among other things, a redefinition of signaling procedures, as well as reducing the number of nodes involved compared to the current UTRAN architecture. This e-NodeB will be able to interconnect with each other and the EPC. The eNodeB will then be responsible for providing nodes termination of user plane protocols and control plane to the user equipment (UE, User Equipment). For its part, the main functions of the E-UTRAN will be the radio resource management (control of radio carriers, radio admission control, dynamic resource allocation in uplink and downlink to the UEs, header compression, encryption or protection of user plane data and routing traffic to the EPC. For his part to the EPC, also known as Core SAE, is considered as the main component of the SAE Architecture. EPC is expected to be an optimized package with a higher data rate, which supports multiple access technologies and also allow new services to support voice and data.

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4.6

General elements of architecture

The following figure shows the network elements of LTE/SAE architecture. Logical nodes and connections shown in this figure represent the basic configuration of the system architecture. It also points to its four main elements: • User Equipment (UE, User Equipment) • Evolved UTRAN (E-UTRAN) • Evolved Packet Core (EPC Evolved Packet Core) • The service layer.

Figure 18 - Main elements of the network LTE / SAE

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EU Areas, E-UTRAN and EPC, together, represent the connectivity layer Internet Protocol (IP, Internet Protocol). This set is what is known as Evolved Packet System (EPS, Evolved Packet System). The main function of this layer is to provide IP-based connectivity, and optimized solely for that purpose. All services are offered via IP, and therefore the circuit switching nodes and interfaces present in previous 3GPP architectures are not present in E-UTRAN and the EPC. For its part, the EU is the device or the end user terminal used for communication. Normally this is a handheld device like a Smartphone or data card (Data card) which are incorporated into a computer.

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4.7

4.7.1

Particular elements of the architecture

The eNodeB

As mentioned earlier, E-UTRAN consists of nodes called eNodeB which are distributed throughout the area of network coverage. That is, E-UTRAN is a mesh of eNodeBs connected via X2 interface. All radio functions are concentrated in them and they represent termination points for all related protocols. In addition, the eNodeB has an important role in mobility management (MM, Mobility Management), as monitors and analyzes the measurements of the radio signal carried out by the EU and himself, and based on that perform decisions handover between cells. It must be remembered that the eNodeB may be serving multiple EU in its coverage area, but each UE is connected to a single eNodeB at a time. The eNodeB had to be connected to the neighboring eNodeBs the transfer can take place. This includes the exchange of signaling transfer between other eNodeBs and the MME. ENodeB functionally acts as a bridge to Layer 2 (data link layer) between the EU and the EPC, being the focal point, using the radio protocols, to the EU, allowing the transmission of data between the EU and EPC, with the latter based on IP connectivity. The eNodeB also performs encryption / decryption of data, data security and compression / decompression IP header, which means avoid repeatedly sending the same data stream in the IP header. The following figure shows the connections that eNodeB to neighboring nodes and summarizes the main features of these interfaces. The eNodeB connections are peer-to-point and point to multipoint.

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Figure 19 - ENodeB connections with other logical nodes and their primary functions

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4.7.2

Entity Mobility Management (MME, Mobile Management Entity)

Mobility Management (MME Mobility Management Entity) is the main element of control in the EPC. The MME also has a direct logical connection to the EU and this connection is used as the main control channel between the UE and the network. The following are the main functions of the MME in a basic configuration of the system architecture: • Authentication and security: When the UE is registered on the network for the first time, the MME initiates authentication by doing the following: seeking permanent identity of the EU in any of the previously visited network, or at the EU, claims that the Home Subscription Server (HSS), the vectors of local network authentication request containing the authentication, sends the request to the EU and EU response compared to those received by the local network. This function is necessary to ensure that the EU is the one who claims to be. The MME also assigns each a unique identity temporary EU Global (Global Unique Temporary Identity, GUTI), so the need to send the permanent identity EU - International Mobile Subscriber Identity (IMSI) - on the radio interface is minimized. • Mobility Management: The MME tracks the location of all EU in its service area. When a UE makes its entry to the network, the MME will create an entry for the UE, and sends the location to the HSS of the network which is the EU. It also asks the right resources in the eNodeB, as well as the S-GW to be selected for the EU. In turn, the MME handles the creation and release of resources based on changes in activity of the EU. The MME is also involved in controlling the handover of the EU between eNodeBs, S-GW or MMEs. MME is involved in each change of eNodeB, as there is a separate Radio Network Controller to monitor these events. • Subscription Management and Service Profile of Connectivity: The MME retrieves the subscription profile in the local network and stores this information for the period in which the EU is in service. This profile determines which network connection data packets should be allocated to the UE in the network. The MME automatically configures the default carrier, which gives the EU the basic IP connectivity. This includes signage eNodeB the CP and e S-GW. The figure bellow shows the MME with logical connections to surrounding nodes, and summarizes the main functions of these interfaces.

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Figure 20 - MME connections to other logical nodes and their main functions.

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4.7.3

SAE GW

The EPC is composed of an element called SAE GW, which is the combination of the two gateways, the Service Gateway (S-GW, Serving-Gateway) and Gateway Packet Data (P-GW, Packet Data Network Gateway) defined for traffic management in the EPC. Its implementation as a single node SAE GW represents one possible scenario, however, the standards define the interface between them, and all operations have been specified for when they are separated. It is important to note that the basic architecture of the system configuration and functionality are documented in 3GPP TS 23.401.This document shows the operation when the S5/S8 interface uses the GTP protocol. However, when the interface protocol used PMIP S5/S8, the functionality of these interfaces is slightly different, and GXC interface is also needed between the Appeal and Collection Policy Functions (PCRF, Resource Policy and Charging Function) and the S-GW. The appropriate places are clearly marked and additional functions are described in detail in 3GPP TS 23.402.The following sections describe the functions together for some cases involving E-UTRAN.

4.7.4

Gateway service (S-GW, Serving Gateway)

The S-GW is part of network infrastructure facilities located in the operator. When S5/S8 interface is based on the GTP, S-GW GTP tunnels will in all User interfaces Plane. The mapping between IP services and the GTP tunnels on P-GW, and S-GW does not need to be connected to the PCRF. All control is related to the tunnel is of GTP, and comes from any MME and P-GW. On the other hand, when using the PMIP S5/S8 interface, the S-GW perform the mapping between IP services and the GTP tunnels in the S1-U interface, and connect to the PCRF to receive mapping information. The S-GW has a minor role in the control functions. Only responsible for their own resources, and maps based on requests from MME, P-GW and the PCRF, which in turn act on the need to create, modify or delete resources for the EU. During the mobility of the EU among eNodeB, the S-GW acts as a local mobility anchor. The MME tells the S-GW to change the tunnel of a eNodeB to another. During the handover thr MME may request the S-GW tunnels to provide resources to relay information eNodeB source to eNodeB target. Mobility scenarios also include changes to a S-GW to another, and the MME handles this change as a result, by eliminating the tunnels of the old S-GW and put in a new S-GW. For all data flows belonging to the EU in connection mode, the S-GW forwards the data between eNodeB and P-GW. However, when the UE is in idle mode, eNodeB resources are freed, and the data path ends in the S-GW. If the S-GW receives data packets from the P-GW in any tunnel, you should ask the MME start EU location, forcing it to connect to the network and when the tunnels are reconnected, the packets are sent to the EU. The S-GW data tracks in tunnels, and may also collect

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data necessary for accounting and charging the user. The next figure shows how the S-GW is connected to other logical nodes, and lists the main functions of these interfaces.

Figure 21 - GW connections with other logical nodes and their primary functions

All these interfaces must be configured in a point-to-multipoint, because the S-GW can only serve a specific geographical area, with a limited set of eNodeBs, and there is also a limited set of MMES that controls that area. The S-GW should be able to connect to any P-GW in the entire network, since the P-GW is not going to change, while the S-GW if you can change when you move the EU. In the above figure also shows the case of indirect data forwarding between eNodeBs through the S-GW. It is clear, yet there are no specifications for the interface name associated between the S-GWs, as the format is exactly the same as in the S1-U interface and S-GWs involved may consider that they are communicating directly with a eNodeB.

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4.7.5

Gateway Packet Data Network (P-GW, Packet Data Network Gateway)

The P-GW, also often abbreviated as PDN-GW is the router boundary between the EPS and external data networks. It is the anchor of the highest level of mobility in the system, given that if a UE moves from an S-GW to another, the P-GW will receive a prompt to change to the new S-GW. In addition, usually acting as the EU IP connection. The P-GW also performs traffic gate functions and filtering as required by the service. Like the S-GW, the P-GW is maintained in a centralized location in the operator's premises. Normally, the P-GW IP address is assigned by the EU and the EU is used to communicate with other hosts on external networks like the Internet. It is also possible that the external PDN the UE is connected to assign the address to use the EU and P-GW tunnels direct all traffic to that network. The P-GW IP performs this assignment by the Dynamic Host Configuration Protocol (DHCP), or query to an external DHCP server, and provides direction to the EU. The P-GW can be configured for IPv4, IPv6 or both protocols as needed. The P-GW performs the synchronization and filtering functions as required by the policies established by the EU and the service. The P-GW also has features for monitoring the data flow for statistical purposes, or for lawful interception. The following figure shows the logical connections to nodes surrounding the P-GW, and lists the main functions of these interfaces. Each P-GW can be connected to one or more PCRF, S-GW and external networks.

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Figure 22 - P-GW connections to neighboring nodes, with per-interface features

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4.7.6

Feature Collection Policy and Resources (PCRF, Policies and Charging Resource Function)

Is the network element that is responsible for the Policy and Charging Control (PCC). Make decisions about how to manage services in terms of quality of service. The PCRF is a server that is normally found with other switching elements. The information provided by the PCRF to the P-GW is known as the PCC rules. The PCRF sends these PCC rules every time a new subscriber is configured. The PCRF PCC may establish rules based on a request from the P-GW and the S-GW in case PMIP and also based on the request of the application function (FA). Each PCRF may be associated with one or more AF, P-GW and S-GW. The connections between the PCRF and the other nodes shown on the next figure.

Figure 23 - PCRF connections with logical nodes and their primary functions

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4.7.7

Local subscriber server (HSS, Home Subscriber Server)

This server represents the subscription database for all users. It also records the user's location in the visited node level control network, such as the MME. The HSS stores information about the subscriber profile, contains information about the services that are applicable to you, including information on PDN connections allowed, and whether or not to allow roaming to a visited network in particular. To encourage mobility between non 3GPP access networks, the HSS also stores the identity of the P-GW in use. The permanent key is used to calculate the authentication vectors are sent to a host network for user authentication and obtain the following keys for encryption and integrity protection, is stored in the Authentication Center (AUC), which is usually part of the HSS. HSS interacts with the MME, ie must be able to contact all MME throughout the network, where the EU in question are allowed to move. For each UE, the HSS records will point to a single MME in use at once and as soon as a new MME informs serve the EU, the HSS will leave the location of the previous MME.

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4.8

Interfaces and protocols in the setting of the basic system architecture

The following figure shows the protocols in the control plane (CP, Control Plane) related to a connection from the EU to a PDN. The interfaces are shown in two parts, one on E-UTRAN protocols (LTE-Uu) and the EU, and other protocols to gateways (S1-MME). The protocols are shown in white are developed by the 3GPP, while light gray background protocols are developed by the IETF, and represent the standard Internet technologies used for transport in the EPS. 3GPP has defined only ways of how to use these protocols.

Figure 24 - Interfaces Protocols LTE-Uu, S1-MME at the EPS control.

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4.8.1

Interface LTE-Uu

LTE-Uu interface is the radio interface between the terminal and the eNodeB. The top layer of the CP is the NAS (Non-Access Stratum), which consists of two protocols (EMM and ESM), which performed in the signaling transport directly between the EU and the MME. The contents of the NAS layer protocols is not visible to the eNodeB, and eNodeB not involved in these operations than the transportation of messages, and provide some guidance on the transport layer. Here are the protocols for LTE-Uu interface.

4.8.1.1

Protocol EPS Mobility Management (EMM, EPS Mobility Management)

EMM protocol is responsible for managing mobility within the EU. It includes features to connect and disconnect the EU's network and performs the update of its location in the middle. This is called a Tracking Area Update (TAU, Tracking Area Updating), and occurs in idle mode. Authentication and identity protection EU, ie the allocation of GUTI (Global Unique Temporary Identity) to the EU, are also part of the EMM layer and control layer encryption and integrity protection.

4.8.1.2

EPS Protocol Session Management (ESM, EPS Session Management)

This protocol can be used to handle the management within the limits of coverage between the UE and MME and is used in conjunction with the management of EUTRAN limits. The ESM has procedures for the application of resources (IP connectivity to a PDN or resources dedicated to the carrier) by the EU.

4.8.1.3

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Protocol Radio Resource Control (RRC, Radio Resource Control)

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This protocol manages the utilization of radio resources. Management signaling and data connections of the UE and includes functions for the handover.

4.8.1.4

Convergent Protocol Packet Data (PDCP, Packet Data Convergence Protocol)

The main functions of PDCP are the IP header compression in the user plane, as well as encryption and integrity protection at the level of control.

4.8.1.5

Protocol Radio Link Control (RLC, Radio Link Control)

The RLC protocol is responsible for the segmentation and concatenation to the interface transmission PDCP-PDU (PDCP-Payload Data Unit). It also performs error correction method of automatic repeat request (ARQ, Automatic Repeat Request).

4.8.1.6

The Medium Access Control (MAC Medium Access Control)

The MAC layer is responsible for scheduling the data according to priorities, and multiplexing of data to layer 1 transport block. The MAC layer also provides error correction with Hybrid ARQ.

4.8.1.7

The physical layer (PHY, Physical)

This is the layer 1 of the LTE radio interface Uu.

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4.8.2

S1-MME interface

S1-MME interface connects with eNodeBs MME (which are connected to the EU). The messages are transferred between the MME and eNodeB through Protocol Application S1 (S1-AP, S1 Application Protocol).NAS messages are transferred between the MME and the EU. S1-MME interface has the following features: • Transportation S1AP messages on SCTP. • NAS message transport in S1AP.

4.8.2.1

S1 Application Protocol (S1AP, S1 Application Protocol)

S1AP EU manages connections, control plane and user between E-UTRAN and EPC, including participation in the handover in the EPC. S1AP service also provides signaling between E-UTRAN and EPC. S1AP services are divided into two groups: • Services not related to EU: These refer to all instances of the interface between ENB and MME S1 using a signaling connection is not associated with the EU. • Services associated with the EU: S1AP Functions that provide these services are associated signaling connection that holds for a specific EU.

4.8.2.2

Protocol SCTP / IP signaling transport

SCTP is a transport layer protocol that provides congestion control sequences to convey messages. SCTP is designed to carry signaling messages over IP.

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SCTP offers the following services to its users: • Error free recognition without duplicating the user data transfer. • Data fragmentation to conform to set the size of the MTU (Maximum Transmission Unit). • Sequential delivery of user messages in multiple channels, in order of arrival of each user's messages. • Grouping of multiple user messages into a single SCTP packet.

4.8.3

S11 interface

The S11 joins the MME interface with the S-GW. As this interface, some other interfaces such as S2, S4, S10 and S10, use the same protocols and communication layers of the system.

Figure 25 - GTP S11 interface protocols - Map control

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The protocols described on the next lines are involved, in the S11 interface.

4.8.3.1

Protocol GPRS Tunneling Protocol, Control Plane (GTPC, GPRS Tunneling Protocol Control Plane)

This protocol manages the connections in the EPC. This includes signaling depending on the quality of service (QoS) and other parameters. GTP-C also performs mobility management within the EPC. The mobility management system of GPRS and UMTS is similar, and is based on the protocol GTP (GPRS Tunneling Protocol) defined by ETSI for mobility management in GPRS networks. Mobility in these systems is achieved below the network layer, link level. Thus, the address of any protocol used in layer 3 is fixed throughout the session data regardless of the location of the mobile terminal and its path across the mobile network coverage. The following figure shows how a session is routed within the GPRS architecture.

Figure 26 - GPRS operation.

In the previous figure is shown how mobile terminal connects to SGSN nearest to send in a GTP tunnel user data to the GGSN in charge of connecting to the data network designated by the user. In GPRS, it is called Routing Area RA (Routing

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Area) to a set of cells, and is identified by a routing area identifier (RAI). A device called SGSN, will handle the service area contains one or more areas of routing. The SGSN is responsible for tracking the terminal for its service area, maintaining and updating location information as the terminal moves. The mobile station sets the session is always connected to the same GGSN, keeping your e-layer 3 (IP address) for the entire data session. Once the session, if the terminal moves it can change from SGSN. Ultimately, the HLR and the GGSN specific services a subscriber must know which SGSN manages mobility of the user at all times.

4.8.4

S5/S8 Interface

S5/S8 interface is the interface that connects the S-GW and P-GW. S5/S8 called because it involves two stages. S5 is called when the S-GW and P-GW in the same PLMN, while if they are in different PLMN is referred to that interface S8. According to the 3GPP there are two main protocols for S5/S8 interface. According to specification 3GPP TS 23.401 may be based on GTP-C protocol, while the specification 3GPP TS 23.402 indicates that may be based on PMIP protocol on the control plane and its equivalent for the user plane and GTP-U GRE. Below are explained the protocols for both specifications.

4.8.5

GTP S5/S8 Interface

The GTP control plane is constructed mainly by two protocols: • GPRS Tunneling Protocol, Control Plane (GTP-C, Control Plane GPRS Tunneling Protocol) handles the connections in the EPC. This includes the signaling QoS and other parameters. If GTP is used in the S5/S8 interface also manages the GTP-U tunnels. GTP-C also performs the functions of mobility management in the EPC. • Protocol Data Unit (UDP / IP) transport. The UDP protocol is used instead of TCP, since the upper layers and reliable transportation services, with error recovery and data re-transmission. With respect to the GTP user plane the next figure shows the layers below the layer of the end user, i.e. level 2 protocols, used to transport IP packets to the end user.

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Figure 27 - User plane protocols

The protocol structure is very similar to the CP. This emphasizes the fact that the whole system is designed for generic data packet transport, and signaling both CPs and the data are ultimately UP packet data. Only the volumes are different. • GPRS Tunneling Protocol, User Plane (GTP-U) GTP-U is used when the type S5/S8 GTP. Form the GTP-U tunnel is used to send IP packets end-user belonging to a node in EPS. It is used in the S1-U interface.

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4.8.6

PMIP S5/S8 Interface

The following protocols are used, when the interface is based on PMIP S5/S8:

Figure 28 - PMIP related protocols

• Proxy Mobile IP (PMIP) in the control plane: PMIP is the alternative protocol for the S5/S8 interface. • Generic Routing Encapsulation (GRE, Generic Routing Encapsulation) in the user plane: GRE is used in the S5/S8 interface in conjunction with PMIP. GRE is an IP in IP tunnel to transport all data belonging to the EU. That is why such protocols are used to interconnect with legacy systems such as LTE and WiMAX CDMA.

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4.8.7

Interface X2

The following figure illustrates the structure of X2 interface protocols.

Figure 29 - Control plane protocols and user interface for X2

It resembles the S1 Interface, only changes to the CP. The interface uses the protocol X2AP in mobility between eNodeBs, including tasks for the preparation of the handover and generally maintaining the relationship between eNodeBs neighbors. In the user plane, the X2 interface is used for data transmission in a transient state during delivery, when the radio interface and is disconnected at the source side, and has not resumed on the destination side. The data transmission is done for downlink data since uplink data can be controlled effectively by the EU. The protocol of this interface is described on the next sections.

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4.8.7.1

X2AP Protocol

X2AP protocol provides the following functions: • Mobility Management: This feature allows you to ENB shift responsibility for control of a certain EU to another ENB. For its part, the transmission of user plane data, the transfer status and context of the EU are part of the management mobility. • Cargo Management: This function is used by eNBs to indicate the status of resources, the overhead and burden of each other. • Notice of general error situations: This function allows reporting of error situations. • Resetting the X2 interface: This function is used to restore the X2 interface. • X2 interface configuration: This feature is used to exchange information necessary for X2 interface configuration of the ENB. • Updated Settings ENB: This feature allows you to update the application-level data necessary for two eNBs to interoperate properly with the X2 interface.

4.8.8

SGI interface

Connecting the P-GW with IP networks is carried out Through the Gi interface and SGI, as shown bellow. The GGSN / P-GW is the domain accessible package for the interoperation with the IP network. In this case, the packet network domain will look like any other IP network or subnet.

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Figure 30 - The protocol stacks GGSN and P-GW to the IP network interworking

From the point of view of the external IP network, the GGSN / P-GW is seen as a normal IP router. L2 and L1 layers are specific to each manufacturer.

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4.8.9

S6a/S6d Interface

The interface connects to the MME S6a the Subscriber Server HSS. Allows the transfer of subscription and authentication data and authorization of user access to the EPS. The SGSN also uses S6d interface to inform the HSS SGSN service area in which the subscriber is located. The interface is based S6d two protocols, the diamater and SCTP, as shown bellow.

Figure 31 - S6d interface protocol

The main objective S6d interface is to enable the HSS to keep track of the location of the user equipment (UE) and provide the SGSN / S-GW subscriber data and authentication. Its main functions are to update location information in the HSS and updates membership data in the SGSN / S-GW. The protocols for this interface are described on the next lines.

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4.8.9.1

DIAMETER Protocol

The DIAMETER protocol whose development is based on the protocol RADIUS, is a protocol that aims to provide new access technologies, authentication, authorization and accounting ( AAA, Authentication, Authorization and Accounting). DIAMETER is designed to work both as local as in a roaming state. The Diameter protocol is so named for being twice the RADIUS in English. (Diameter is twice the radius). The Diameter protocol can offer the following services: • Delivery partners "Attribute Value" (AVP, Attribute Value Pairs). • Negotiation skills. • Reporting errors. • Extensibility, through addition of new commands and AVP. • Basic services required by applications, such as management of user sessions or log. The AVP is the most important object of the DIAMETER protocol, are used to send all data. Some AVP DIAMETER need them to run their own, while others are used to transmit proprietary data applications using DIAMETER. The AVP leading application-specific information can be added freely to the DIAMETER message, provided the necessary AVP are present, and those that are added are not explicitly prohibited by the rules of protocol. The DIAMETER AVP needs to provide its features are used to: • Transport authentication information in order that the DIAMETER server to authenticate users. • Transport service-specific information between clients and servers, allowing participants to decide whether or not the access request from a user. • Exchange information about resource usage, which may be required to register, capacity planning, etc. • DIAMETER redirect messages through a server hierarchy. • These AVP, DIAMETER is able to provide the minimum requirements to implement a solid AAA architecture. For its part, the SCTP protocol shown above has already been described.

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4.8.10

Rx Interface

The Rx reference point is used to exchange information between the applications and services and the application function (AF). As defined in specifications 3GPP TS 23 203, this information is part of the input used by the PCRF. The next tables summarize the protocols and interfaces in the basic configuration of the system architecture.

Summary of LTE interface protocols according to 3GPP specifications Interface

Protocol

LTE-Uu

CP: RRC / PDCP / RLC / MAC / PHY

3GPP TS 36,413, "Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial

Specification

UP: PDCP / RLC / MAC / PHY

Radio Access Network (E-UTRAN); Overall description (Release 8). "

CP: X2AP/SCTP/IP

3GPP TS 36,423, "Evolved Universal Terrestrial Radio Access Network (E-UTRAN); X2 Application Protocol (X2AP) (Release 8)."

UP: GTP-U/UDP/IP

3GPP TS 29,274, 'Evolved GPRS Tunnelling Protocol (Gtoe) for EPS (Release 8). "

S1-MME

S1AP/SCTP/UDP/IP

3GPP TS 36,413, "Evolved Universal Terrestrial Radio Access (E-UTRA); S1 Application Protocol (S1AP) (Release 8)."

SI-U

GTP-U/UDP/IP

3GPP TS 29,274, 'Evolved GPRS Tunneling Protocol (Gtoe) for EPS (Release 8). "

S10

GTP-C/UDP/IP

3GPP TS 29,274, 'Evolved GPRS Tunneling Protocol (Gtoe) for EPS (Release 8). "

S11

GTP-C/UDP/IP

3GPP TS 29,274, 'Evolved GPRS Tunneling Protocol (Gtoe) for EPS (Release 8). "

S5/S8 (GTP)

GTP / UDP / IP

3GPP TS 29,274, 'Evolved GPRS Tunneling Protocol (Gtoe) for EPS (Release 8). "

X2

CP: PMIP / IP

S5/S8 (PMIP)

UP: GRE / IP

SGI

IP (also Diameter & Radius)

S6A

Diameter / SCTP / IP

3GPP TS 29,275, 'PMIP based Mobility and Tunneling protocols (Release 8). "

3GPP TS 29,061, 'Inter-working Between the Public Land Mobile Network (PLMN) Supporting packet based services and Packet Data Networks (PDN) (Release 8). "

3GPP TS 29,272, 'MME Related Interfaces Based on Diameter Protocol (Release 8). "

Figure 32 - Summary of LTE interface protocols according to 3GPP specifications (I)

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Interface

Protocol

Specification

Gx

Diameter / SCTP / IP

3GPP TS 29,212, "Policy and charging control over Gx reference point (Release 8)."

GXC

Diameter / SCTP / IP

3GPP TS 29,212, "Policy and charging control over Gx reference point (Release 8)."

Rx

Diameter / SCTP / IP

3GPP TS 29,214, "Policy and charging control over Rx reference point (Release 8)."

EU - MME

EMM ESM

3GPP TS 24,301, "Non-Access-Stratum (NAS) protocol for Evolved Packet System (EPS) (Release 8)."

Figure 33 - Summary of LTE interface protocols according to 3GPP specifications (II)

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4.9

System Architecture and E-UTRAN access networks legacy

The following sections are devoted to details of the architectures and protocols of the 3GPP and non 3GPP networks coupled with a network in LTE / EPC.

4.9.1

Interconnection infrastructure architecture Bequeathed LTE 3GPP

The following figure describes the architecture and network elements defined by 3GPP. The items referred to are the Access Nodes (ANs, Access nodes), E-UTRAN and GERAN, which are connected to the EPC.

Figure 34 - System architecture based on 3GPP SAE

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This architecture is called 3GPP Interworking System Configuration Architecture which allows the interconnection and interoperability between access networks mentioned. Functionally the E-UTRAN, the UTRAN and GERAN similar provide connectivity services, especially from the user point of view, where the differences may be the different data rates and an improvement in performance. From the point of view of architecture access nodes are quite different. For example, there are big differences in how the bearers or carriers are handled in the EPS, compared with existing access networks UTRAN or GERAN. However, when UTRAN or GERAN are connected to the EPC, could continue to operate as they do today from this perspective, and for this purpose the S-GW assumes the role of the GGSN (GPRS Support Node). Again optimized network environment with E-UTRAN, GERAN access nodes and UTRAN work the same way as they do when they interact. The differences become more visible in the EPC, because it was the GGSN is the S-GW, which can be modified with the SGSN for mobility of the EU. For the coexistence of these networks, the EPC requires new interfaces and functions that allow the interconnection and interoperation with UTRAN and GERAN. The corresponding functions will also be required by the GERAN and UTRAN. The new interfaces are the S3, S4, and S12 as shown above. The interface from the SGSN to the HSS can also be updated S6d interface (which uses the Diameter protocol), but the use of existing MAP protocol assigned to the Gr interface also can be reused. Consequently, the evolved Node B (eNodeB) has no direct interface with other 3GPP access nodes and interaction with the EPC is the same. However, the optimized network environment means that the network will be able to make the control of mobility events such as handovers and provide the functionality to maintain communication allowing minimal disruption of services. This means that ENB must have the ability to coordinate the user equipment (UE, User Equipment), monitoring the UTRAN and GERAN cells, and improve handover decisions based on measurement results, and thus interface protocols E-UTRAN radio should be added to support new functions. Similar aggregates will be required for UTRAN and GERAN to support handover to E-UTRAN.

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Summary of additional protocols and interfaces to interconnect with legacy networks 3GPP EPS

Interface

Protocols

Specification

S3

GTP-C/UDP/IP

3GPP TS 29,274, 'Evolved GPRS Tunneling Protocol (Gtoe) for EPS (Release 8). "

S4

GTP / UDP / IP

3GPP TS 29,274, 'Evolved GPRS Tunneling Protocol (Gtoe) for EPS (Release 8). "

S12

GTP-U/UDP/IP

3GPP TS 29,274, 'Evolved GPRS Tunneling Protocol (Gtoe) for EPS (Release 8). "

S16

GTP / UDP / IP

3GPP TS 29,274, 'Evolved GPRS Tunneling Protocol (Gtoe) for EPS (Release 8). "

S6d

Diameter / SCTP / IP

3GPP TS 29,272, 'MME Related Interfaces Based on Diameter Protocol (Release 8). "

Figure 35 - Summary of additional protocols and interfaces to interconnect with legacy networks 3GPP EPS

The explanation of the previous interfaces corresponds to the following: • S3 interface between the MME and SGSN. It uses the same protocols and interface layers S1 explained above. • S4 interface between the SGW and the SGSN. It uses the same protocols and interface layers S1 explained above. • S12 interface between the SGW and the RNC. It uses the same protocols and interface layers S1 explained above. • S16 interface between different SGSN. It uses the same protocols and interface layers S1 explained above. • S6d interface between the HSS and the SGSN. It uses the same protocols and interface layers S6A explained above.

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4.9.2

Interfacing with legacy infrastructure 3GPP CS

To summarize, bellow it is indicated the additional protocols and interfaces that allow the EPS to interact with legacy systems of circuit switching.

Summary of protocols and additional interfaces for interconnection with 3GPP CS Core Network.

Interface

Protocols

Specification

SGs

SGsAP / SCTP / IP

3GPP TS 29,118 Mobility Management Entity (MME)-Visitor Location Register (VLR) SGs interface specification (Release 8)

Sv

GTP-C (subset) / UDP / IP

3GPP TS 29,280, '3 GPP Sv EPS interface (MME to MSC) for SRVCC (Release 8). "

Figure 36 - Summary of protocols and additional interfaces for the interconnection of 3GPP CS

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4.10

Interconnection Architecture LTE infrastructure Bequeathed No - 3GPP

The general architecture for interconnecting networks of the non-3GPP is shown bellow

Figure 37 - System architecture for access networks and non-3GPP 3GPP

This figure shows two types of nodes non 3GPP. They are the trusted nodes (reliable) and untrusted nodes (not reliable).

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4.10.1

User Equipment

The interconnection between the nodes of non-3GPP access requires the user equipment for supporting the radio technologies and specific mobility procedures. Mobility procedures depend on whether the optimizations are performed or not.

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4.10.2

Evolved Packet Core (EPC)

The EPC has additional features to support the non-3GPP access nodes. The main changes are in the P-GW, PCRF, HSS, and in the S-GW. Additionally, new elements have been introduced as EPDG (Evolved Packet Data Gateway) and the AAA server. The fllowing figure highlights the AAA server connections and functions for non3GPP access nodes.

Figure 38 - Interfaces and main functions of the 3GPP AAA server

The P-GW is the focal point for mobility for access node (AN Access Node). P-GW node also connects to the AAA server, which connects to the HSS. This link is made to tell the HSS database selected the P-GW. In this way this is enabled for a user with mobility between non 3GPP AN, they authenticate and authorize the mobility using the S2C interface. Each P-GW can be connected to more than one AAA server. The EPDG is a node dedicated to control the user equipment (UE) and the connection between networks when a node non-3GPP access is connected to the EPC. The AAA server checks the authenticity of the user and informs the AN on its output. Depending on the AN at issue, the AAA server can also send information about the user profile to the AN that best serves the user.

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4.10.3

Non-3GPP access network reliable

The term reliability for non-3GPP nodes AN (AN Access Node and Access Nodes) refers to those networks that are reliable and capable of reliability defined by the 3GPP. The security specification 3GPP Release 8 for non-3GPP access nodes states that have improved the protocol extensible authentication method for authentication and key agreement for 3rd Generation (EAP-AKA, Extensible Authentication Protocol Method for 3rd Generation Authentication and Key Agreement). The procedures relating to this have been improved on the interface Shasta supports the delivery of information relating to user profiles from the server Authentication, Authorization and Accounting (AAA, Authentication, Authorization and Accounting (AAA) / HSS) to access nodes (AN) and its loading data from access nodes to the AAA server, which are typical functions required in mobile networks

4.10.4

Access networks unreliable non-3GPP

The concepts of the architecture that apply to non-3GPP access nodes are unreliable inherited from the wireless local area networks (WLAN IW, Wireless Local Area Network Inter-Working) originally defined in Release 6. One of the main functional requirements for Release 8 is that ANs should take the specific function of packet delivery. A data security tunnel is established between the EU and a specific node called Gate Enhanced Packet data (EPDG, Enhanced Packet Data Gateway) using the interface SWU, and delivery of packages from these nodes takes place through that tunnel.

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4.10.5

Main elements of the Interconnection System

One of the main elements is the P-GW, which is responsible for carrying out the role of mobility, and that is where they connect 3GPP access nodes, using this S2a interfaces (connecting nodes are not reliable 3GPP) and S2B (connecting nodes untrusted non-3GPP). Both use the IP control layer mobility using the PMIP protocol. For networks that do not support PMIP, client mode is enabled MIPv4 Foreign Agent (MIPv4 Foreign Agent Client Mode) as an option in S2a. In addition to the functions of mobility, the architecture includes interfaces for authentication of user equipment (UE) to the nodes of non-3GPP access and also allows the functionality and Charges Policy Convergence (PCC, Policy and Charging Convergence) in them GXA and interfaces using Gxb. However Gxb interface is not specified in Release 8. Another scenario, which provides additional flexibility is called scenario S8 and S2a/S2b chain. In this scenario the non-3GPP access nodes are connected to the SGW located in the Public Land Mobile Network (PLMN, Public Land Mobile Network) accessed through the interfaces S2a or S2b, while the P-GW will be located in home network or local PLMN network. This allows the visited network, offer users roaming the use of non-3GPP access nodes which are not necessarily related at all with the local operator, even in cases where the P-GW is located on the local network PLMN. This scenario requires that the S-GW improve certain functions that normally belong to the P-GW for this node serves as a terminal for S2a or S2b interfaces.

4.10.6

Interfaces and protocols for the interconnection of the 3GPP networks

As discussed above, to connect 3GPP networks to EPC it are required additional interfaces. The figure bellow shows these interfaces. For each interface, the relevant specification as well as the supported protocol is depicted.

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Summary of protocols and additional interfaces for the interconnection of the EPS to Non-3GPP networks Interface

Protocols

Specification

S2a

PMIP / IP, orMIPv4/UDP/IP

3GPP TS 29,275, 'PMIP based Mobility and Tunneling protocols (Release 8). "

S2b

PMIP / IP

S2C

DSMIPv6, IKEv2

S6B

Diameter / SCTP / IP

Gxa

Diameter / SCTP / IP

3GPP TS 29,212, "Policy and charging control over Gx reference point (Release 8)."

Gxb

Not defined Release 8

N/A

STa

Diameter / SCTP / IP

3GPP TS 24,303, "Mobility management based on Dual-Stack Mobile IPv6 (Release 8)." 3GPP TS 29,273, 'Evolved Packet System (EPS) EPS 3GPP AAA interfaces (Release 8). "

SWA

Diameter / SCTP / IP

SWD

Diameter / SCTP / IP

SWM

Diameter / SCTP / IP

SWN

PMIP

SWU

IKEv2, MOBIKE

SWx

Diameter / SCTP / IP

3GPP TS 29,273, 'Evolved Packet System (EPS) EPS 3GPP AAA interfaces (Release 8). "

3GPP TS 29,275, 'PMIP based Mobility and Tunneling protocols (Release 8). " 3GPP TS 24,302, 'Access to the Evolved Packet Core (EPC) via non-3GPP access networks (Release 8). " 3GPP TS 29,273, 'Evolved Packet System (EPS) EPS 3GPP AAA interfaces (Release 8). "

3GPP TS 24,304, "Mobility management based on Mobile IPv4; User Equipment (UE) - foreign agent interface (Release 8)."

EU - foreign agent in trusted non-3GPP Access

MIPv4

EU - Trusted or Un-trusted non-3GPP access

EAP-AKA

3GPP TS 24,302, 'Access to the Evolved Packet Core (EPC) via non-3GPP access networks (Release 8). "

Figure 39 - Summary of protocols and additional interfaces for the interconnection of the EPS to Non-3GPP networks

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5

Aspects of LTE Radio

The following chapter discusses issues related with the radio interface used on the LTE Technology.

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5.1

Definition of the radio interface

To connect subscribers with base stations, radio links are established using a carefully defined communication protocol, called the radio interface. The radio interface (IR) should ensure high reliability in the channel to ensure that data is correctly sent and received between the mobile and base station.

5.1.1

Access Technologies

LTE radio interface uses Multiple Access Orthogonal Frequency Division (OFDMA, Orthogonal Frequency Division Multiple Access) in the downlink and the Division Multiple Access Single Carrier Frequency (SC-FDMA Single Carrier Frequency Division Multiple Access) the uplink. These techniques are very suitable for the operation of flexible bandwidth. This enables operators to deploy LTE in different frequency bands and bandwidths available. Addition, access in both directions is done through technology Multiple Input Multiple Output (MIMO, Multiple Input Multiple Output).

5.1.1.1

OFDMA

This technique is a multiuser version of the Multiplexing Orthogonal Frequency Division (OFDM). It is used to get a set of users of a telecommunication system to share the spectrum of a certain channel. Multiple accesses is achieved by dividing the channel, which allows you to split the transmission of data and sending them in different subcarriers. The next figure illustrates this principle of multiple carriers.

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Figure 40 - Principle of multiple carriers

Regarding this aspect, the OFDM technique seeks to these subcarriers are orthogonal in frequency. Orthogonal channels, avoiding the use of guard bands while allowing efficient use of spectrum. In turn, each of the subcarrier are modulated with a conventional technique is like QPSK , 16QAM or 64QAM. The modulation / demodulation "classic" OFDM, are complex execution and adjustment. However the feasibility of a performing these operations using Digital Signal Processing (DSP), through discrete Fourier transforms, • Discrete Fourier Transform (DFT, Discrete Fourier Transform). • Inverse Discrete Fourier Transform (IDFT, Inverse Discrete Fourier Transform). There is an algorithm called FFT (Fast Fourier Transform) which allows fast and efficient calculation of the DFT and IDFT, which has promoted the application of these transformations to modern digital communications. Thus the application of FFT to the OFDM allows a compact, efficient and economical use of signal processing. This is how the implementation of OFDMA is based on the use of Fourier transform (FF, Fast Fourier Transform) and inverse transform (IFFT, Inverse Fast Fourier Transform) to move between the domains of time and frequency. The FFT moving a signal from time domain to frequency domain and IFFT does in the opposite

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direction. So in LTE using the FFT and IFFT receiving the transmission as shown bellow.

Figure 41 - OFDMA transmitter and receiver

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5.1.1.2

SC-FDMA

The transmission through a single carrier (SC, Single Carrier) means that the information is modulated only in a carrier, adjusting the phase, amplitude or both on the carrier. SC-FDMA is a multiple access technique that uses a single carrier in the transmission of information, using both in FDD and TDD. Its modulation is by quadrature amplitude modulation (QAM, Quadrature Amplitude Modulation). Unlike FDMA uses low power for transmission. The LTE uplink uses this technique to simplify design and reduce energy consumption. Thus the ratio of peak to average power (PAPR) in SC-FDMA does not grow with the bandwidth used. SC-FDMA in the FFT and IFFT are used for both the transmitter and receiver. The equalization is done at the receiver after passing through the stage of the FFT, so the effects of fading in frequency and phase distortion fall. The transmission and reception system with SC-FDMA as well as the transmission using SC-FDMA from the terminals to the radio base is shown on the next figures.

Figure 42 - Transmitter and receiver SC-FDMA

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Figure 43 - Transmission from terminals to the radio base with SC-FDMA

In summary, the following illustrates how working OFDMA and SC-FDMA. As shown in bellow, in OFDMA pass through "M" symbols in parallel, dividing the bandwidth between them, each symbol has a duration equal to the symbol time. In SC-FDMA pass through "M" symbols sequentially each occupying the entire available bandwidth and with a length equal to a symbol of the time.

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Figure 44 - Performance of OFDMA and SC-FDMA

The figure shows a sequence of four QPSK symbols, each of them modulating its own sub-carrier (shown in figure four) in the appropriate QPSK phase. After a period of OFDMA symbol, may be a time (so that no duplication) before the next symbol period. In SC-FDMA, each symbol is transmitted sequentially. Thus, the 4 symbols are transmitted in the same period of time (1 / M). Each symbol used all the available width. After four symbols left to avoid overlapping time above.

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5.1.2

MIMO (Multiple Input Multiple Output)

The use of multiple antenna systems in uplink and downlink, known as MIMO is another important feature of LTE. In recent years MIMO technology has been widely used in wireless communications and significantly increases the rate of transfer of information through different channels in the transmission of data or spatial multiplexing by multiple antennas physically separated. According to the architecture have the following variants: • MIMO: Multiple input multiple output, this is the case in which both transmitter and receiver have multiple antennas. • MISO: Multiple Input Single output, in the case of several broadcasting antennas but only one receiver. • SIMO: Single input multiple output, in the case of only one transmitting antenna and multiple antennas at the receiver.

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Figure 45 - Access modes and Radio channels

MIMO systems offer significantly higher data rates and are therefore an essential component of LTE. The principle of spatial multiplexing MIMO is sent signals from multiple antennas and receiving those signals through multiple antennas. The arrangement of these antennas are increased by a factor of 2 (eg arrays of 2x2 and 4 x 4). These transmit signals from different antennas are evaluated by the receiver as the signal to noise ratio (SNR, Signal Noise Ratio) and this way take advantage of physical phenomena such as multipath propagation to increase the transmission rate and reduce the error rate, increasing the spectral efficiency of wireless communication system.

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5.1.3

Element and resource block

A resource element is the smallest unit in the physical layer and occupies a symbol OFDM or SC-FDMA in the time domain and a subcarrier in the frequency domain. A resource block (RB) is the smallest unit that can be scheduled for transmission. RB physically occupies a 0.5 ms (1 slot) in the time domain and 180 kHz in frequency domain. This is shown bellow.

Figure 46 - The resource network for uplink (a) and downlink (b)

5.1.4

Downlink transmission

As mentioned above, the LTE downlink transmission is based on (OFDM). The following figure shows the time-frequency grid for the link descent in LTE, where each element of the resources corresponds to a subcarrier OFDM over an interval of OFDM symbol. A resource block corresponds to 12 OFDM subcarriers of 15 KHz each one, during a slot time (timeslot) of 0.5 ms.

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Figure 47 - DL resource allocation

The symbol time is chosen to 66.7µs LTE. This choice is based on radio channel average delay spread (a measure of the dispersion of time on the radio channel) and the coherence time (a measure of how times change radio channel).The symbol time should be much longer than the delay spread in order to maintain the inter-symbol interference (ISI Inter Symbol Interference) low. In addition, the cyclic prefix must be greater than the expected delay spread in order to completely eliminate the ISI. However, if the symbol time is too long (ie longer than the coherence time), the radio channel will change considerably in a symbol. This would lead to interference between Carriers (ICI, Inter Carrier Interference).

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5.1.5

LTE OFDM cyclic prefix, CP

There are two truly remarkable aspects of OFDM. First, each OFDM symbol is preceded by a cyclic prefix (CP), which is used to effectively eliminate ISI. Second, the sub-carriers are very tightly spaced to make efficient use of available bandwidth, yet there is virtually no interference among adjacent sub-carriers (Inter Carrier Interference, or ICI). These two unique features are actually closely related. In order to understand how OFDM deals with multipath distortion, it’s useful to consider the signal in both the time and frequency domains. In areas where inter-symbol interference is expected, it can be avoided by inserting a guard period into the timing at the beginning of each data symbol. It is then possible to copy a section from the end of the symbol to the beginning. This is known as the cyclic prefix, CP. The receiver can then sample the waveform at the optimum time and avoid any inter-symbol interference caused by reflections that are delayed by times up to the length of the cyclic prefix, CP. The length of the cyclic prefix, CP is important. If it is not long enough then it will not counteract the multipath reflection delay spread. If it is too long, then it will reduce the data throughput capacity. For LTE, the standard length of the cyclic prefix has been chosen to be 4.69 µs. This enables the system to accommodate path variations of up to 1.4 km. With the symbol length in LTE set to 66.7 µs. The symbol length is defined by the fact that for OFDM systems the symbol length is equal to the reciprocal of the carrier spacing so that orthogonality is achieved. With a carrier spacing of 15 kHz, this gives the symbol length of 66.7 µs. Cyclic Prefix (CP). A cyclic prefix consists of the last few symbols of the output from IFFT and is placed in front of the IFFT output, which together with the output make up a whole frame. It is used to preserve the orthogonality property over the duration of one transmissed signal and also as guard symbols to remove the ISI. There are two cyclic-prefix lengths defined: Normal cyclic prefix and extended cyclic prefix corresponding to seven and six SC-FDMA symbol per slot respectively. • Normal cyclic prefix: TCP = 160 Ts (SC-FDMA symbol #0) , TCP = 144 Ts (SC-FDMA symbol #1 to #6) • Extended cyclic prefix: TCP-e = 512 Ts (SC-FDMA symbol #0 to SC-FDMA symbol #5)

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5.1.6

Uplink transmission technique

In contrast to the downlink, the uplink resource blocks allocated to a mobile terminal should always be consecutive in the frequency domain.

Figure 48 - UL resource allocation

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5.2

Access modes and frequency bands LTE.

In this section we examine the access modes and frequency bands used by LTE.

5.2.1

Access Modes

LTE has a duplex property, ie there is a transmission and reception at both ends. Since both share the same communications medium, it is necessary to establish some mechanism to control access. The main methods are FDD and TDD. LTE supports both FDD (Frequency Division Duplex) and TDD (Time Division Duplex). Bidirectional Transmission Technique for Frequency Division (FDD, Frequency Division Duplex) is based on the use of two different frequency bands for transmission, one for sending and another for the reception. This technique is also used in second generation mobile telephony (GSM) and third generation (WCDMA). For its part, the Bidirectional Transmission Technology Time Division (TDD, Time Division Duplex), unlike the FDD technique, using a single frequency band for sending and receiving information, sharing of transmission periods. The figure bellow shows both modes of transmission.

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Figure 49 - Frequency division duplex vs time

There are advantages and disadvantages to using both methods. TDD has more overhead and latency due to frequent switching time. TDD mode is also easier to implement in areas with limited spectrum available. For its part, FDD has the advantage of not having to resort to temporary guard bands as in TDD. This means that this technique is best suited to voice traffic, since it allows for a minimum delay, but nevertheless requires a more expensive implementation, mainly for the purchase of a license to operate in the spectrum. The disadvantage is having to resort to good crossover filters (since they are usually gang related). These filters are called duplexers. Despite this there is a mode called half duplex FDD (HD-FDD), where the EU does not have to transmit at the same time receiving information. Therefore, the EU can be manufactured at a lower cost because the duplex filter is not necessary.

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5.2.2

Supported frequency bands.

LTE specifications include the frequency bands identified for UMTS. There are currently 15 blocks operating in FDD and TDD bands 8. The following figure shows the current distributions of these frequencies.

LTE operating frequency E-UTRA operating Band

Uplink data (UL)

Downlink data (DL)

Duplex Mode

1

1920 - 1980 MHz

2110 - 2170 MHz

FDD

2

1850 - 1910 MHz

1930 - 1990 MHz

3

1710 - 1785 MHz

1802 - 1880 MHz

4

1710 - 1755 MHz

2110 - 2155 MHz

FDD

5

824 to 840 MHz

869 to 894 MHz

FDD

6

830 to 840 MHz

875 to 882 MHz

FDD

7

2500 - 2570 MHz

2620 - 2690 MHz

FDD

FDD FDD

8

880 to 915 MHz

925 to 960 MHz

FDD

9

1749.9 - 1770 MHz

1844.9 - 1879.9 MHz

FDD

10

1710 - 1770 MHz

2110 - 2170 MHz

11

1427.9 - 1452.9 MHz

1472.9 - 1500.9 MHz

FDD

12

688 to 716 MHz

728 to 746 MHz

FDD

13

777 to 787 MHz

746 to 756 MHz

FDD

14

788 to 798 MHz

758 to 768 MHz

FDD

704 to 716 MHz

734 to 746 MHz

FDD

33

1900 - 1920 MHz

1900 - 1920 MHz

TDD

34

2010 - 2025 MHz

2010 - 2025 MHz

TDD

35

1850 - 1910 MHz

1850 - 1910 MHz

TDD

36

1930 - 1990 MHz

1930 - 1990 MHz

37

1910 - 1930 MHz

1910 - 1930 MHz

38

2570 - 2620 MHz

2570 - 2620 MHz

TDD

39

1880 1820 MHz

1880 1820 MHz

TDD

40

2300 - 2400 MHz

2300 - 2400 MHz

TDD

FDD

... 17 ...

TDD TDD

Figure 50 - LTE operating frequency

5.2.3

Bandwidth of transmission

LTE must support international radio regulations, so these specifications include frequencies ranging from 1.4 to 20 MHz with 15 kHz subcarrier. The following figure shows the number of resource blocks allocated to the different bandwidths of the channel.

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Figure 51 - Bandwidth of Channel

The spectrum flexibility incorporates the ability to use both FDD and TDD effectively. Furthermore, support for the operation in six different bandwidths, 1.4, 3, 5, 10, 15 and 20 MHz, plays an important role flexibility on the part of the spectrum in the normalization of the radio interface.

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5.3

Radio layers and protocols used in LTE

Similar to WCDMA / HSPA, as well as most other modern communication systems, the transformation is indicated for LTE is structured in different protocol layers. Although several of these layers there are some differences or new protocols involved, be recalled and noted that the architecture of the LTE radio access node is a unique, eNodeB. This section contains an overview of protocol layers and their interaction. An overview of the LTE protocol architecture for the downlink is shown bellow. LTE protocol structure connected with the transmission in the uplink is similar to the structure of Downlink.

Figure 52 - LTE transmission (downlink) structure

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The protocols involved are described below: • Packet Data Protocol Convergence (PDCP) performs IP header compression to reduce the number of bits transmitted through the radio interface. The header compression mechanism is based on Robust Header Compression (ROHC), a header compression algorithm standard that is also used in WCDMA, and several other mobile communication standards. PDCP is also responsible for encryption and integrity protection of data transmitted. On the receiving side, PDCP protocol performs the corresponding decryption and decompression operations. There is a PDCP entity for SAE bearer configured for a mobile terminal. • Radio Link Control (RLC) is responsible for the segmentation / concatenation, manipulation of the broadcast, and streaming delivery to higher layers. Unlike WCDMA, RLC protocol is located in the eNodeB since there is only one type of node in the LTE network architecture. Segmentation of RLC offers services to the PDCP in the form of radio bearers. • Media Access Control (MAC, Media Access Control): is responsible for hybrid ARQ transmissions and uplink and downlink. Planning functionality found in the eNodeB, which has a MAC entity per cell, for both uplink and downlink. Hybrid ARQ protocol is present in both transmission and reception end of the MAC protocol. The MAC serves as the RLC logical channels. • The physical layer (PHY) is responsible for encoding / decoding, modulation / demodulation, multi-antenna allocation, and other typical physical layer functions. It also offers services to the MAC layer in the form of transport channels.

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5.3.1

Radio Link Control (RLC)

Similar to WCDMA / HSPA, LTE RLC is responsible for the segmentation / concatenation of IP packets, also known as RLC SDUs, the PDCP in appropriate sizes RLC PDU .Also handles the retransmission of erroneously received PDUs, and the elimination of duplicate PDUs received. Finally, the RLC is secured in sequence SDU delivery to higher layers. Depending on the type of service, the RLC can be configured in different ways to carry out some or all of these functions. Segmentation and concatenation, one of the main functions of RLC. It are shown bellow .Depending on the decision of the planner, a certain amount of data is selected for transmission buffer of the RLC SDU and the SDU are segmented / concatenated to create the RLC PDU.

Figure 53 - RLC segmentation and concatenation

The RLC retransmission mechanism is also responsible for preventing data delivery errors to the upper layers. To accomplish this, a retransmission protocol operates between RLC entities in the receiver and transmitter. By monitoring the sequence numbers of incoming PDU, the RLC receiver can identify any missing PDU. Status reports are fedback to the transmitting entity requesting the retransmission of missing PDUs. Based on the status report received, the RLC entity at the transmitter can take appropriate action and forward the PDU is missing if necessary.

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5.3.2

Media Access Control (MAC)

The MAC layer handles the multiplexing of logical channels, hybrid ARQ retransmissions, and the planning of the uplink and downlink. LTE only defines a cell because there is no uplink diversity.

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5.3.3

Logical channels and transport channels.

MAC serves as the RLC logical channel. A logical channel is defined by the type of information that has and is generally classified as a control channel used for transmission control and configuration information necessary for the operation of an LTE system, or a traffic channel, used for user data. The whole logical channel types specified for LTE include:

MAC layer transport channels Downlink Transport Channel Type

Description

Downlink shared channel DL-SCH

(Downlink shared channel)

Broadcast Channel BCH (Broadcast Channel)

Paging Channel PCH (Paging Channel) Channel multicast addresses MCH (Multicast Channel)

Functions

Support for HARQ, the modulation of dynamic linking, dynamic resource allocation and semi-static, discontinuous reception EU and MBMS transmission. Capable of being transmitted throughout the coverage area of the cell to allow beamforming.

Transport fixed format Must be conveyed throughout the coverage area of cell

EU support for discontinuous reception. Must be transmitted throughout the cell coverage area, assigned to physical resources.

Support MBSFN, resource allocation, semi-static should be disseminated throughout the area of cell coverage

Uplink Transport Channel Type

Description

Functions

Shared data channel ascendants

Support for dynamic link adaptation, HARQ, dynamic, and semi-static resource allocation possibility to use beamforming

UL-SCH (Uplink Shared Channel) Random Access Channel RACH

Information control limit, the collision risk (Random Access Channel)

Figure 54 - MAC layer transport channels

Part of the functionality of the MAC is the multiplexing of different logical channels and the mapping of logical channels appropriate transport channels. The assignments of support among the logical channels and transport channels will be shown for downlink and uplink on the following figures. The figures clearly show how DL-SCH and UL-SCH are the downlink and the main transport channels for uplink, respectively.

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Figure 55 - Mapping the downstream channels

Figure 56 - Mapping the upstream channels

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5.3.4

Physical Layer

The physical layer is responsible for the coding, physical layer HARQ processing, modulation, multi-antenna processing, and mapping the signal to a physical resource. It also handles the mapping of transport channels to physical channels. A simplified view of the transformation of the DL-SCH is shown bellow. As mentioned before, the physical layer offers services to the MAC layer in the form of transport channels. In the downlink, the DL-SCH is the main channel for data transmission, but the treatment of PCH and MCH is similar.

Figure 57 - Simplified view of the DL-SCH

The verification rate is used not only to match the number of bits of code to the amount of resources allocated for the DL-SCH transmission, but also to generate different versions of controlled redundancy HARQ protocol. After comparing cases, coded bits are modulated by QPSK, 16QAM or 64QAM, followed by the mapping of the antenna. The latter can be configured to provide different patterns of multi-antenna transmission, including transmit diversity, beamforming and spatial multiplexing. Finally, the output of the process of the antenna is attached to the physical resources used to DL-SCH. For its part, the physical layer processing of the UL-SCH is closely monitoring the processing of DL-SCH. However, the MAC scheduler in the eNodeB is responsible for selecting the transport format of the mobile terminal and the resources to be used

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for uplink transmission. In addition, the UL is not compatible with spatial multiplexing, and therefore no allocation of the antenna in the uplink. Both the uplink and downlink reference signals are (RS), known as pilot signals in other standards, which are used by the receiver to estimate the amplitude and the phase of the received signal. Without the use of the RS, the changes in phase and amplitude of the received signal demodulations produce unreliable, especially in high modulations such as 16QAM or 64QAM.

LTE physical signs Downlink physical signs

Purpose

Primary synchronization signal

Used for cell search and identification the cell id (One of three orthogonal sequences)

Secondary synchronization signal

Used for cell search and identification by the EU. Take the rest of the cell identification (One of the 168 binary sequences)

Reference signal

It is used to estimate the downstream channel. The exact sequence derived from the cell id (One of 3 x 168 = 504 pseudo random sequences)

Uplink physical signs

Purpose

Reference signals (demodulation and sounding)

It is used for synchronization of the EU and the estimated uplink channel

Figure 58 - LTE physical signs

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A physical channel corresponds to the time-frequency resources used for the transmission of a particular transport channel and each transport channel is assigned to a corresponding physical channel.

Figure 59 - Channel Mapping

Having the description of the different channels may illustrate the mapping of each channel resource blocks as follows:

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Figure 60 - Example mapping of signals in different channels and resource blocks for downlink

In addition to the physical channels with a corresponding transport channel, there are also physical channels without a corresponding transport channel. These channels L1/L2 known as channels, are used for downstream control information (DCI), which provides the terminal with the information necessary for the proper reception and decoding of downlink data and control information for uplink (UCI) is used to provide the planner and the hybrid ARQ protocol with the necessary information on the situation in the terminal.

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The physical type channels that are defined in LTE are:

Physical channels DL Channels

Full Name

Purpose

Physical Broadcast Channel PBoC

Take the information specific to the cell (Physical Broadcast Channel) Physical Multicast Channel

PMCH

Take the transport channel MCH (Physical Multibroadcast Channel) Physical Control Channel Data Descending

PDCCH

Planning ACK / NACK (Physical Downlink Control Channel) Shared physical data channel downstream

PDSCH

Billing Information (Physical Downlink Shared Channel) Physical Control Channel Format Indicator

PCFICH (Physical Control Channel Format Indicator)

Defines the number of OFDMA symbols PDCCH by subplot (1, 2, 3 or 4)

Physical channel Hybrid-ARQ indicator PHICH

HARG carries ACK / NACK (Ph ysical Hybrid-ARQ Indicator Channel)

UL Channels

Full Name

Purpose

Physical Random Access Channel Prach

Call Initialization (Physical Random Access Channel) Physical Control Channel Data Ascending

PUCCH

Planning ACK / NACK (Physical Uplink Control Channel) Physicists Canal Ascending Copart Data

Pusch

Billing Information (Physical Uplink Shared Channel)

Figure 61 - Physical channels

Keep in mind that some of the physical channels, in particular, control channels used for downlink (PCFICH, PDCCH, PHICH) and control information uplink (PUCCH) do not have a corresponding transport channel. This can be found on the following specifications: • 3GPP Technical Specification, TS 36,211, "Evolved Universal Terrestrial Radio Access (E-UTRA), Physical channels and modulation", 3GPP, September 2008 v 8.4.0. • 3GPP Technical Specification, TS 36,212, "Evolved Universal Terrestrial Radio Access (E-UTRA), Multiplexing and channel coding ', 3GPP, v 8.4.0, September 2008. • 3GPP Technical Specification, TS 36,213, "Evolved Universal Terrestrial Radio Access (E-UTRA) Physical layer procedures', 3GPP, v 8.4.0, September 2008. • 3GPP Technical Specification, TS 36,214, "Evolved Universal Terrestrial Radio Access (E-UTRA) Physical Layer Measurements', 3GPP, v 8.4.0, September 2008.

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5.4

Frame structure

The physical layer supports both multiple access systems described above: OFDMA in the downlink and SC-FDMA in the uplink. It is also supported for even and odd spectra using frequency division duplex (FDD) and time division duplex (TDD), respectively. Although the downlink and uplink use different access schemes, they share a common frame structure. The frame structure defines the frame, slot, and symbol in the time domain. Two radio frame structures are defined for LTE and shown bellow.

Figure 62 - LTE Frame Structure Type 1.

The frame structure type 1 is defined for the FDD mode. Each radio frame is 10 ms long and consists of 10 sub-plots. Each sub-frame contains two slots. In the FDD, the uplink and downlink using the same structure despite the use of different spectrum.

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Figure 63 - LTE Frame Structure Type 2, 5ms of periodicity in the switch

The frame structure type 2 is defined for the TDD mode. An example is shown in above.This example is for a period of 5 ms at the point of switching and is composed of two half-frames of 5 ms for a total duration of 10 ms. The subplots consist of a link up or down, or the transmission of a special subframe containing downlink and uplink pilot time slot (DwPTS and UpPTS) separated by a guard period of transmission (GP, Guard Period).The distribution of uplink subframes, descending, and special subplots is determined by one of the seven configurations.

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5.5

Modulation

Permitted signs and channel modulation schemes for downlink and uplink are shown bellow.

Modulation schemes for the downlink and uplink LTE Downlink

Downlink channels

Modulation scheme

PBoC

QPSK

PDCCH

QPSK

PDSCH

QPSK, 16QAM, 64QAM

PMCH

QPSK, 16QAM, 64QAM

PCFICH

QPSK

PHICH

BPSK modulated in the I and Q with diffusion factor 2 or 4 Walsh codes

Physical Signs

Modulation scheme

Reference signal

Pseudo random sequence complex I + jQ (sequence length Gold-31) derived from Cell ID

Primary Synchronization

One of the three sequences Zadoff-Chu

Secondary Synchronization

Two sequences of 31 bit BPSK M Uplink

Physical Channels

Modulation scheme

PUCCH

BPSK, QPSK

Pusch

QPSK, 16QAM, 64QAM

Prach

Uth Zadoff-Chu root

Physical Signs

Modulation scheme

Demodulation RS

Zadoff-Chu

RS probe

Chu Zadoff-based

Figure 64 - Modulation schemes for the downlink and uplink in LTE

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5.6

Data Flow

To summarize the flow of downlink data across all layers of protocols, an illustration of an example for a case with three IP packets, two in a radio carrier and one on another radio carrier, is given on the figure bellow The data flow in case of uplink transmission is similar. The PDCP performs optionally the IP header compression l, followed by encryption. A PDCP header is added to decode the mobile terminal. The output of the PDCP fed to the RLC. The RLC protocol performs concatenation and / or segmentation of PDCP SDU and RLC adds a header. The header used in delivery sequence (logical channel) in the mobile terminal and the identification of RLC PDU for retransmission. The RLC PDU is sent to the MAC layer, which has a number of RLC PDU, the SDU meets on a Mac, and inserts the MAC header to form a transport block. The transport block size depends on the instantaneous velocity data using the link adaptation mechanism. Therefore, the link adaptation affects both the MAC and the RLC processing. Finally, the physical layer attaches a CRC in the transport block for error detection purposes, performs coding and modulation, and transmits the resulting signal through the air.

Figure 65 - Example of data flow in a transmission

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5.7

EU states and zone concepts

LTE is developed to have a flatter architecture (fewer nodes) and minus signs (fewer messages) to UTRAN. In addition, the number of EU states may have (for RRC states) fell from 5 in UTRAN (DETACHED, IDLE, URA_PCH, CELL_FACH, CELL_DCH) and only 3 in LTE (DETACHED, IDLE and CONNECTED) (Off, Off, On).

Figure 66 - EU states in LTE

Moreover, the concept that simplifies zone compared to UTRAN. LTE in a single area of mobility is defined idle mode, Area Monitoring (Tracking Area, TA). In UTRAN, the routing area RA (Routing Area) and area of signs up UTRAN (URA UTRAN Routing Area) is defined for the PS traffic and location areas (LA, Localization Areas) for CS traffic. In ECM-IDLE (EPS idle connection management) of the EU's position is known only to the network at the level of support, while in ECM-CONNECTED EU location is known at the cell level by the ENB. When a UE is connected to the network is assigned an IP address of a P-GW. The IP address is maintained regardless of whether the EU goes into sleep mode or not, provided it is connected to the network, but is released when EU emerges from the network.

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Bellow the categories are depicted.

Figure 67 - EU states mobility

5.8

Rates of end user data, EU capabilities

It is estimated that the data rate for LTE ideally have ranges of 100 to 326 Mbps in the downlink and 50 to 86 Mbps in the uplink depending on configurations of antennas and modulation. The following table shows the results of some tests with various arrays of antennas and different terminals divided into categories depending on the capacity of bandwidth to download or upload according to 3GPP TS 36,306

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Categories, different uplink and downlink antenna arrays

EU Status

Downlink peak data rate (Mbps)

Downlink antenna configuration (ENB transmitters x receivers EU)

Peak uplink data rate (Mbps)

Support 64QAM uplink

Category 1

10.29

1x2

6.16

Not Supported

Category 2

51.02

2x2

25.45

Not Supported

Category 3

102.04

2x2

51.02

Not Supported

Category 4

150.75

2x2

51.02

Not Supported

Category 5

302.75

4x2

75.37

Yes

Figure 68 - Categories, downlink and uplink with different antenna arrays

For any transmitter output power is a key metric. However, measuring equipment should ensure that all EU-development can be measured in the same way. As defined by the 3GPP LTE, the compliance test involving power transmission and power output. The metrics evaluated under the category of transmission power include maximum output power (MOP, Maximum Output Power), peak power reduction (MPR Maximum Power Reduction), and the EU further reduction of peak power (A-MPR Additional maximum power reduction).The output tests are applied to control power, minimum power output, and transmit power. For LTE uplink, the power output is not a simple measure with a single maximum value for each category of EU. In actual use, a UE cannot transmit the excess energy it has the potential to interfere with other UEs and adjacent systems. MOP defines the maximum transmit power in the channel bandwidth of all channels of the transmission bandwidth (NRB) As an example, take the Category 3, the first category has been real progress in the measurement of output power. It has been standardized (3GPP TS 36,101 V8.3.0) power and tolerance.These powers are transmitted to UEs with a maximum of 4 bands of operation. For UEs that support 5 or more bands are expected to descend power each additional band.

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LTE Band

Cat 1

Tolerance

Cat 2

Tolerance

(DMB)

(DB)

(DMB)

(DB)

Cat 3 (DMB)

23.

1 to 17

Tolerance

Cat 4

Tolerance

(DB)

(DMB)

(DB)

±2

(200 mW)

...

33 to 40

23.

±2

Figure 69 - EU transmit power.

Note: The table is incomplete in the specification TS 36.101. The modulation is also related to the bandwidth of transmission.

Bandwidth of channels / Settings-bandwidth transmission (R8) MPR (dB)

Modulation 1.4 MHz

3.0 MHz

5 MHz

10 MHz

15 MHz

20 MHz

QPSK

>5

>4

>8

>12

>16

>18

≤1

16 QAM

≤5

≤4

≤8

≤ 12

≤ 16

≤ 18

≤1

16 QAM

>5

>4

>8

>12

>16

>18

≤1

Figure 70 - Reduction of peak power, bandwidth and modulation

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6

Considerations for LTE Radio Spectrum

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6.1

Overview of Radio Spectrum

Spectrum is known as a portion of the electromagnetic spectrum occupied by radio waves, in other words, used mainly for telecommunications. Spectrum is a valuable resource and time limited, it is necessary to make a rational and efficient use of it. At present there is a growing demand for spectrum for new wireless services consolidation, as evidenced by, among others, mobile communications systems, networks of terrestrial digital TV broadcasting or the various systems of wireless broadband access. This growing demand is necessary to add that not all parts of it with the same characteristics, resulting in different coverage capabilities or different properties from noise and interference, love of technology or cost implications. Also different types of information (voice, audio, data and video) require margins of spectrum (frequency bands) specific. All these features lead to so far have been found in some specific areas of the spectrum are particularly suited to provide some specific services, including, at times, inevitable conflicts between different services competing for the same frequency band.

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6.2

Actors involved in spectrum management

Considering the trend of offering broadband services using wireless systems, and its time considering that end-users, in their role as purchasers of services and recipients of public telecommunications services, they need among other things, to have sufficient spectrum to enjoy new applications and services that require this broadband, competition is predicted by the acquisition of spectrum by different stakeholders. These actors include: • Equipment manufacturers and telecommunications Emperor: The operators offer services based on a technology and using standard equipment features. This is how the radio equipment are negotiated between manufacturers of such equipment and operators of telecommunications services. Because of this telecom operators must comply with the frequency recommended by the operators who are in the vanguard, who ultimately encourage the frequencies at which it must operate a given technology, taking into consideration the characteristics and availability of spectrum they possess. Failure to do so, each operator would have to manufacture equipment (eg mobile devices) on a small scale, making the unit cost will be higher. • Regulators: The radio spectrum is a public good. In each country there is a controller that manages the use of frequency bands in it. The regulatory body acting under its "National Plan of Frequency Allocations" and the rules and recommendations, international, has the power of management, administration and control of radio spectrum, including the powers attributed to certain uses, specific bands assign frequencies to specific users and monitor their correct use.

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6.3

LTE spectral efficiency

In telecommunications, the spectral efficiency is a measure to know how well used is a particular frequency band when transmitting data ( bits ).The higher the value, better exploited is that bandwidths mathematical definition is defined by the following formula:

Where E is the spectral efficiency, R the transmission rate in bps ( bits / s ) and B the bandwidth of the channel in Hz, therefore, the spectral efficiency is measured in bps / Hz (bits / second / Hertz). One of the priorities that are looking to LTE, is to improve spectral efficiency. Below is a comparison between the LTE and other technologies.

Spectral efficiency of mobile technology

Technology

Spectral Efficiency (bps / Hz)

GPRS

0,07

W-CDMA

0,4

HSDPA

2,8

HSPA + 2x2

8,4

LTE

5

LTE 2x2

8,6

LTE 4x4

16,3

Figure 71 - Comparative spectral efficiency

Visible as the incursion of new technologies much more efficient, as is the case of LTE, will allow better use of the spectrum.

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6.4

Spectrum bands allocated for LTE

The international body 3GPP has identified some of the bands identified for UMTS LTE, also support FDD (Frequency Division Duplex) and TDD (Time Division Duplex).The Agency has identified 15 bands for FDD mode operation and 8 bands for LTE TDD operation, which gives operators the flexibility to adjust their networks, spectrum and existing business objectives for mobile broadband services. The figure 50 above indicated the current distributions of these frequencies. As noted in the table, the ranges defined for LTE frequency range from 700 MHz to 2.6 GHz bands also mentioned, there are others that are in the process of study such as the digital dividend (790 - 862 MHz), 3.5 GHz in the band from 3400 to 3600 and in 3.7 GHz band of 3600 to 3800.

6.4.1

Frequency bands currently used for LTE

Today, some telecom operators are investing in order to acquire sufficient spectrum to enable them to deploy LTE. Of the available bands for LTE, which are being most desirable for the implementation of this technology are: The 700 MHz band, the band of 1.7 and 2.1 GHz and 2.6-GHz band. Three operators are betting on LTE in these bands are listed below: • NTT DoCoMo (Japan) in the 2.1GHz band. • Verizon Wireless (USA) in the 700MHz band. • TeliaSonera (Sweden and Norway) in the 2.6GHz band.

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6.4.2

Aspects to consider when choosing the frequency of implementation

Moreover, when comparing two of the bands for LTE world (the 700 MHz compared to 2.6 GHz), in terms of coverage of 700 MHz provides better coverage and requires using fewer base stations as shown in the following figures:

Figure 72 - Frequency bands and radio coverage ranges required bases

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Figure 73 - Comparative frequency coverage as used in LTE

As you can see, higher frequencies have smaller propagation distances, but have a greater capacity for data transmission. In economic terms, these characteristics determine the infrastructure costs to allocate. A better spread means less investment in base stations.

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For example, if we compare the use of 700 MHz compared to other higher frequencies, the network infrastructure, network costs (CAPEX) are approximately 4.5 times less than if we use the 2.5 GHz band and about 1, 3 times if you used the 850 MHz band.

CAPEX relative percentage required for investment in network infrastructure

1230%

1400%

1200%

1000%

675% 800%

455% 600%

328% 400%

126%

100% 200%

0%

700

850

2100

2500

3500

5800

Frequency (MHz)

Capex

Figure 74 - Comparative CAPEX investment by the spectral band used

That is, the option of deploying LTE in the frequency band of 700 MHz, turns out to be the optimal choice if you are looking for great coverage with little infrastructure, contributing to reducing the digital dividend. Furthermore, as noted above, for the operator this will represent a reduction of costs associated with the implementation of the network.

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Today the 700MHz band is currently used for UHF television services, as happens today in most European Countries. Regarding this aspect, with the conversion of analog to digital television (DVBT, which will free up a significant portion of radio spectrum in the 700MHz band, called digital dividend. The following figure provides the portion of spectrum allocated for digital dividend, with the range of 698-806 MHz that is allocated for this purpose.

Figure 75 - Spectrum plan mobile and digital TV

6.4.3

The choice of refarming as an alternative implementation

Today, some telecom operators are considering future reuse of existing GSM and UMTS bands for LTE deployment. This process of reusing or rearranging of the radio spectrum when deploying a new radio technology is known as "Spectrum refarming." This is because the cost to the operator to make purchases of new spectrum. Therefore most of the operators should consider the possibility of reorganization of the spectrum so that it is reused for LTE. However, the operator considers this possibility should have sufficient amount of spectrum to efficiently support LTE technology, while using the remaining spectrum to support the traffic of other legacy technologies. This requires cooperation and coordination not only between the parties concerned, but also with the relevant regulator.

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6.5

Amount of spectrum required for LTE deployment

An important consideration is to know the amount of spectrum needed to provide the service capacity offered by LTE. LTE current specifications suggest that rates could provide more than 300 Mbit / s per cell. However, this applies and requires the optimal configuration of the antennas and radio ideal conditions, any of which can be assumed at this stage of study. More realistically, the configurable maximum bandwidth of 20 MHz, the estimated maximum data rate (peak) of 100 Mbit / s is estimated that for this bandwidth, an average of 40 to 50 Mbit / s may be achievable. These figures are further reduced if the available bandwidth is reduced, as shown bellow.

Attainable speeds with LTE

Bandwidth (MHz) Speeds 1.4.

3

5

10

15

20

Pico (Mbps)

4.5.

9

20

40

60

100

Average (Mbps)

2.2.5.

4.5.

10 -12

20 -25

35 -40

40-50

Peak with 2x2 MIMO (Mbps)

12,04

25,8

43

86

129

172

Peak with 4x4 MIMO (Mbps)

22,82

48,9

81,5

163

244,5

326

Figure 76 - Attainable speeds with LTE

Based on the above, an operator with spectrum in FDD mode shall be at least 2x20 is 40 MHz to deploy LTE in its maximum capacity.

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7

Other considerations on a migration to LTE

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The evolution of LTE could be said to be implemented (the first stages with the analog FDMA network and the second digital TDMA).Subsequently gave rise to three clearly defined stages. The first of these steps was the implementation of a GSM / GPRS, the second was the implementation of a UMTS / HSPA, as a third stage aims to deploy an LTE network in all terms of access and core packages. The goal of migration is to implement a converged mobile network capable of supporting GSM, 3G/HSPA + & LTE. That is, taking into account the design and development of the LTE, the emphasis is to ensure future interoperability with existing 3GPP technologies, 3G/HSPA + and GSM. This will ensure that HSPA + and LTE to coexist, and being LTE technology that complements HSPA +, providing increased capacity in areas of high demand. Initial implementations of LTE will be most appropriate in specific urban areas of high demand, while that HSPA + will cover the vast existing HSPA coverage. The figure bellow shows the migration to LTE which international markets have bet, as it is considered that LTE is the technology that will prevail in the medium and long term.

Figure 77 - Migration Trends in mobile technology LTE

How you can see, it is estimated that 88% of the markets tend to use the evolutionary path marked with number 1, namely GSM - UMTS - LTE.

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There are several factors that a Telecom operator should take into account when moving towards LTE. Among others, we can identify three main parts, which can impact heavily on the successful development of this technology in the coming years: • Economic aspect: It is imperative that the operator takes into account the investments to be made for the deployment of network and parallel to the market environment, will allow future will recover investments made in the implementation of this technology. • Regulatory environment: Indicates the legal framework under which govern the networks and services. In this regard, an operator must have sufficient spectrum for the deployment of this technology. • Technological requirements: A telecommunications operator shall evaluate the existing offerings in terms of terminals and network equipment so that you can implement this technology. At the same time must take into account the technical requirements for the implementation of an LTE network, assessing the possibility and need for new applications and services can coexist in a converged environment, allowing the interconnection of these networks with existing 2G namely, 3G and Wimax. To summarize, the figure bellow indicates these and other aspects to be considered for migration to LTE.

Figure 78 - Planning stages for LTE cell

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7.1

Special considerations must take into account an operator

In addition to the above considerations, bellow it will be listed a series of more specific issues, recommended for the evolution to LTE.

7.1.1

Considerations for network planning

Planning involves three stages, which are depicted bellow:

Figure 79 - Planning stages

They correspond to the initial planning stage (Initial Planning), detailed planning (Detailed Planning) and finally the stage of optimization (Optimization Planning).

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7.1.2

Initiation stage

This first stage is to gather information about the networking features to be developed, such as aspects of coverage desired capacity, quality of service to be allocated (QoS), and the portfolio of services to be provided. It also includes the amount of expenditures to be allocated to cover their CAPEX and OPEX. In turn, the system must meet the necessary regulatory requirements, among other things.

7.1.3

Stage details

This step involves sizing issues such as estimating traffic by user, location of existing base stations sites, coverage predictions and estimated capacity, which are required for detailed planning of the network. This stage can be divided into the following processes: • Site Selection: In cellular systems, site selection is an important aspect to consider. Also includes the number of sites required, key performance indicators (KPIs, Key Performance Indicator) with respect to coverage and capacity. • Coverage and capacity planning: For LTE, the planning capacity and coverage is interrelated. The main objective in the planning of network capacity that supports LTE is the requirements of user traffic. For its part, the main target for coverage planning is to ensure network availability and their services in designated service areas. • Configuration Planning: The objective of this process is complete the setup of equipment needed for the access and transport networks can provide applications and services that supports LTE and allow interoperability with legacy networks, namely 2G 3G and WiMAX.

7.1.4

Optimization stage

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7.1.5

Deploying services over LTE

When deploying services over LTE networks, a telecommunications operator would have the following choices: 1. LTE network dedicate solely to provide data services. 2. Dedicate LTE network to offer data services and offering voice service on 2G and 3G networks. 3. Using the LTE network to provide voice and data services. This shows that an operator could start using its LTE network to deliver and support it and data services continue to offer voice service from their 2G and 3G networks. At a later stage could offer this new network voice over LTE. Another option is that the operator choose the first instance to provide both services on their networks LTE, ie without going through steps 1 and 2 above. The following sections explains in more detail these three strategies.

7.1.5.1

LTE data services

The advantage of offering these services exclusively, is that the operator will deploy a more agile LTE access network independent, so do not require complex modifications and adjustments to its core network to provide voice service. The above can be seen on the next figure.

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Figure 80 - LTE IP network for data services

The previous strategy would allow a convergence of mobility and access to data services using multiple technologies. This means having a seamless mobility between LTE and legacy technologies (2G/3G), which is critical to ensure the best coverage and access to services that the user has at any time and from anywhere.

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Initially, the deployment of LTE technology, could be done in areas of high traffic (known as Hot-Zones) established by the operator or operators interested in deploying the technology. The above is shown on the next figure.

Figure 81 - Areas LTE

For his part, although users could not achieve the same speed of access outside the network coverage LTE, a future operator would deliver multiple access devices (compatible with LTE, GPRS and UMTS) to enable them to parity and transparency of services used by the user and also allows the user to stay connected.

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7.1.5.2

Session continuity solutions for data services

There are three mechanisms that can be used in the packet core to reach an interconnection "soft" between LTE and legacy networks 3GPP 2G and 3G. The mechanisms are: Handover method in the packet network 23.401 TS specification defines a general procedure for Inter-RAT Handover using the S-GW as an anchor point for all 3GPP radio access technologies. In order to support this new concept, and SGSN must be updated to support new interfaces S3 and S4.The specification or sheet describes the nomenclature to distinguish the S4 SGSN Release 8 of the previous version, which supports the Gn and Gp interfaces. The next figure illustrates this method.

Figure 82 - Handover method specification in Packet Network TS23.401

The new S4 interface can be used to direct data routing so that packets in transit, while the handover is executed, it can be sent to the respective access technology, minimizing packet loss in transit. This feature, along with the IdleMode Signaling Reduction (ISR) are the two main advantages of this method of Release 8.

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Incorporation of MME 23,401 TS specification defines the method Release 8 for interworking access technologies (I-RAT interworking) requires SGSNs in the network are also upgraded or replaced. The main premise of this method indicates that the MME is incorporated into 2G-3G legacy networks as another SGSN and the PGW acts as a GGSN. The multi-mode terminal that also supports or has the ability to LTE will be coupled to the network using the P-GW/GGSN, macro anchor point for mobility, as shown in the figure below:

Figure 83 - P-GW/GGSN macro anchor for mobility

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IDLE mode signaling Assuming LTE access antennas are installed on the same radio base which holds 2G and 3G, when a user equipment (UE) performs the handover from 2G-3G to LTE, has to perform a procedure called TAU, which if successful, deregister the user to the 2G-3G network and recorded in the HSS to use LTE. For his part, when you handover from an LTE network coverage to a network of 2G-3G coverage, it will perform a procedure called RAU and will be deregistered LTE network. This procedure results in a kind of effects such as "ping-pong" with common procedures RAU / TAUS and records related to the mobility of user equipment in idle-mode. This increases the signaling traffic. The next figure shows the trajectory of a UE entering a region with LTE coverage area and because it enters TAU procedure followed by the procedure RAUs when you leave these areas.

Figure 84 - Handover 2G-3G to LTE and vice versa

This effect occurs when there are multi-mode terminals in the network. Importantly, the data card (Data cards) are not expected to generate this effect, but have the capacity for multi-mode, do not tend to have the ability to handover from the point of view of mobility. 3GPP proposes a technique to simultaneously perform the RA and TA. This technique, known as the Idle-Mode Signaling Reduction or ISR, proposed not to increase the signal when the EU is going through a border to change radio

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technology coverage. EU User Team ISR mode will be simultaneously registered in both technologies and re-selected cells in both technologies. RAU recording is activated or TAU only if there is a change in the EU has mobilized off the lists TA or RA. The benefit of ISR leads to increased paging due to EU should be paged in both technologies. Due to the need for simultaneous paging, the ISR architecture that supports must be compatible with a user plane common anchor for the two radio technologies. The 3GPP Release 8, the common anchor point is located in the S-GW. Therefore, when a packet arrives at the S-GW and sent to a UE in idle mode benchmarks S4 and S11 can be used to make the paging request to initiate the MME and SGSN. It is important to note that the method of I-RAT interworking cannot be used to support ISR, since in this case the common anchor point is the P-GW and the page cannot be initialized from it. ISR is based on the network is capable of supporting I-RAT according to the specification TS 23.401 of Release 8 so that the S-GW becomes the anchor point for the 3GPP technologies. As a minimum, the legacy SGSN they should do the upgrade to support the S3 and S4 interfaces and a new interface S6d at HSS. Therefore, the method Release 8 has the advantage of eliminating Idle mode signaling through dual RAT records, but this requires updating the existing SGSNs pass S3/S4 interfaces. The method described in the specification is more practical 23.401 TS cannot require them to SGSNs upgrade.

7.1.6

Voice over LTE

While LTE has the advantage of being a fully network packet switching, has the disadvantage that services like voice calls and SMS messaging, today's major revenue generators for mobile operators, no preliminary be available from an LTE access network, since they are based on circuit switching. To counter this problem, 3GPP has made several solutions to counter this problem, it will be described below.

7.1.7

Circuit switch fallback (CS fallback)

CS-Fallback solution (specified in 3GPP TS 23.272), is based on 2G-3G networks to provide voice services over LTE and allows subscribers to LTE terminals transition to a circuit switched network for 2G-3G receiving voice services. Although CS-Fallback

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introduces a time delay in the establishment of the call, that inherently leads to other concerns of the subscriber such as the need for voice communication and SMS messaging keep the same coverage, and that there is transparency and parity of services. To implement CS-Fallback, operators must offer devices with the ability of CSFallback and perform the "upgrade" their MSCs to support the SGs interface. SGs interface provides a logical connection between the 2G-3G MSC and LTE MME. It is based on the Gs interface (TS23.0.60), which is between the 2G-3G MSC circuit switched domain (CS) and 2G-3G SGSN located in the packet switching network (PS). Regarding the operation of this method, as shown bellow, there is an interface that is the MSC SGs to the MME to achieve paging. S3 interface MME far to the SGSN provides the continuation of an active data session while the user equipment makes handover from an LTE network to a 3G network.

Figure 85 - CS Fall back for handover between 3GPP networks

SGs interface can also be used to support the delivery of SMS messaging on LTE. The registration process of the terminal to the network is initiated when a device able to support GSM / UMTS / LTE is added to the LTE network and further requests that it be registered on the GSM / UMTS available. This record is held by the MME, which acts as an SGSN and MSC suggests that the terminal is connected to the 2G/3G network. The MME 2G/3G MSC must provide the location where is located the theory, information extracted from the LTE network to which the terminal is already attached.

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SMS service for the terminal can remain in the LTE network. To receive a message, the message is forwarded from the MSC to the MME with the interface Gs / SGs and there with RRC signaling on the LTE radio network to the terminal. The shipment from an LTE terminal is similar but is not required to return to the legacy networks. No doubt the use of this mechanism for voice and messaging is not as simple as one might think at first, but it can function as an intermediate solution for voice while establishing a concrete mechanism to provide these services over IMS.

7.1.8

Solution VoLGA

As explained above, LTE is a wireless technology based data access in an all-IP. Given that an organization called Volga Forum has proposed a solution known as Voice over LTE through Generic Access (Voice Over Generic Access via LTE or Volga) which aims to provide mobile operators the ability to provide voice and messaging services through LTE access networks based on 3GPP standard called Generic Access Network (GAN).Using this standard GSM, UMTS and LTE, VoLGA has the ability to provide mobile subscribers voice services, SMS and other services based on circuit switching, when they make the transition years between the 3GPP access technologies, leveraging existing 2G-3G network.

Figure 86 - Volga solution for supporting voice services in LTE

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VOLGA solution requires a driver access network (Vance, VoLGA Access Network Controller), which must be added to the core of the current GSM / UMTS. This driver will support the creation of IP tunnels in order to provide messaging services and Voice over LTE. From the point of view of the LTE network, the VANC connects to the P-GW over IMS interface. For the other teams behave more like an IP node. Now from the point of view of the circuit switched network VANC connects to GSM and UMTS MSC as the first VANC sees as a BSC while the latter sees it as a RNC. In addition to support voice and SMS is not necessary to amend the various nodes connected to Vance. When a terminal is initialized and detects the LTE network, the first thing to do is register with the MME. The MME retrieves subscriber information from HLR / HSS. After that proceed to establish the connection to the VANC, which requires an IP address which can be stocked earlier in the terminal or obtained via a DHCP server. Since the IP terminal establishes an IPSec tunnel toward the VANC and then register with the MSC using the protocol DTAP (Direct Transfer Application Part).

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For the process of handover from a GSM network or UMTS to LTE, the process is as follows: • When the eNodeB detects that the terminal can be served better by cells of a GSM / UMTS, instructs the device to make measurements of signal strength for these cells. Based on this information the eNodeB tells MME is required to perform the handover • The MME informs the VANC that the handover will be performed by a message indicating the identification of the target cell and the subscriber identification • The Vance uses this information to create a message of handover that is standardized. If the destination cell is attached to the same MSC that VANC, then the process is prepared locally and the handover takes place once the cell is ready. If you are connected to another MSC initiates a standard procedure for inter MSC handover.

Figure 87 - Volga process for handover between 3GPP networks

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7.2

Offer LTE-capable terminals to allow for QoE

Operators looking to deploy LTE will need to offer terminals that support multiple access technologies with networks that enable mobility and service continuity between GSM, GPRS, UMTS and LTE. Parallel to this, subscribers to LTE expect a better service, which includes improved speed and applications over 3G. Moreover, a comprehensive coverage including 2G-3G interoperability is essential, hence the need to offer terminals to obtain better performance with respect to what offer 2G-3G terminals today, for voice services and new multimedia applications. Linked to this, the user is looking to have quality of experience (QoE, Quality of Experience).QoE takes into account any factor that contributes to the perception of service by the user and this includes factors such as speed, bandwidth, coverage area, mobility, cost, customization, etc. To provide QoE, according to user expectations, then discusses two critical factors to consider in the implementation of LTE systems: • LTE terminal must be capable of processing high data rates with low latency. • The LTE system will provide transparency and parity of services to the mobile terminal. This means that the terminal must allow access technology agnostic, allowing users to stay connected (always on). In general, today's 3G networks do not offer to subscribers in the service quality data. Instead, today's users are subject to the best effort when access to data services.

7.2.1

Election of the terminal (UE)

When choosing the terminals should be taken into account the preferences that the user has. Other critical factors include multimode terminals, multi-band terminals, capable IPv4/IPv6 and skills as SRVCC or CS-Fallback. These considerations are extended as follows:

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7.2.2

Multimode terminals

In order to provide the user with a wider coverage, not only needs to build an architecture that allows the coexistence of 2G, 3G and LTE. Also need to provide this capability multimode terminals. This will allow the user access to services, regardless of the technology used.

7.2.3

Multiband terminals

To complement the feature of multimode, several radio frequency bands for LTE enabled. For this reason, the operator must ensure that the user has access to multiband devices with this capability that allows users to enjoy mobility, equality and transparency of service. For example, mobile operators in Europe and Asia use different frequency bands that are also used in North America. Depending on the operator and the country, European and Asian operators using the frequency bands of 900 MHz (GSM) 1800 MHz band (DCS) and 2100 MHz band (WCDMA). In North America, you use the 700 MHz band, 800 MHz (mobile), 1700/2100 MHz (AWS), and 1900 MHz (PCS). Some other important features that the user equipment must support are: • Handover for voice between LTE and 3G networks, the terminal requires SRVCC support capacities. • Turn requires support CS-Fallback capabilities. • A terminal that supports VoLGA defines its capacity for voice services, it also requires a set of requirements for interacting with the IMS platform. • The voice terminals operating in LTE required to have location capabilities. One of this method is the Assisted Global Positioning System (AGPS). • LTE terminals must also support services such as SMS.

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7.3

Quality of Service (QoS)

Just as we defined an architecture for Quality of Service (QoS) end-to-end UMTS, with the appearance of evolved packet system (EPS) is also necessary to define a set of parameters and mechanisms in order to ensure quality of service in this new system. Recalling that EPS is the set of SAE with LTE, EPS has significant improvements in the quality of service in relation to 3GPP systems that precede it.

7.3.1

EPS architecture and quality of service

For EPS architecture is clearly defined with attributes and functions to achieve a quality point to point service.

Figure 88 - Architecture EPS QoS bearer channels

Service quality point to point means you must have a service carrier and EPS external carrier, the latter in order to support services and from outside the network nodes. The EPS bearer service is a service carrier and a carrier radio access.

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7.3.2

EPS Carrier

Considering the qualities of an "All IP" and the nature of bursts in data services, from 3GPP Release 8 introduces the concept of EPS carrier, called from now on as "carrier" for simplicity. The carrier is a concept from which identifies packet flows receive the same treatment in terms of quality of service between the terminal equipment (UE) and the gateway PDN-GW. PDP context is equivalent to the standards used in 2G/GPRS and 3G/UMTS. The carrier is composed of three elements, namely: • S5 Carrier: implemented through a tunnel that transports packets between the S-GW and the PDN-GW • S1 Carrier: implemented through a tunnel that transports packets between the S-GW and eNodeB • Radio carrier, implemented by a protocol connection with RLC (Radio Link Control) between eNodeB and the EU.

Figure 89 - EPS carrier elements and their location in the network

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The elementary stream data in EPS is known as SDF (Service Data Flow).This flow is characterized by five aspects: source IP, destination IP address, source port, destination port and protocol for identifying the protocol is over IP. This serves to determine points where the flow begins and ends, and to determine which application or service is in use. In the terminal there is a carrier for each class of service quality and IP address, which means that a terminal can have both multiple IP addresses assigned using different services and therefore have different carriers associated with multiple qualities of service. The carrier is the differentiating factor that facilitates traffic allocation quality of service requirements. You can define two types of carriers as a key differentiating factor: the carriers with a guaranteed bit rate (GBR, Guaranteed Bit Rate) and those that do not guarantee (non GBR, non Guaranteed Bit Rate). Then one can assume that a service using a carrier GBR no packet loss due to congestion, which is carried out by the different admission control functions located in different network nodes. With the other type of carrier cannot be assured the above. A GBR carrier to carry out its function properly you need to reserve network resources, so that its place is not for long periods, while a non-GBR bearer does not reserve resources so if your facility allows for longer periods time. Similar to the classification of carriers GBR and no mention is made of dedicated carriers or default. The default carrier is set when the terminal is connected to the network and is maintained by the terminal while maintaining the same IP address. Because the carrier is maintained for long periods then classified as non-GBR. To provide different qualities of service to different packet flows requires the use of dedicated carrier, which can be GBR or not RBM. The mapping of packet flows is dedicated to carrying through policies in the network that can be modified by the network operator.

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7.3.3

QoS parameters

EPS carrier is characterized by the following parameters: • Allocation and retention priority (ARP Assignation Retention Priority): refers to priority mechanisms used for allocation and retention. This parameter is used for example in cases where there is congestion and must decide which carriers are preserved and which discarded. • Guaranteed bit rate (GBR, Guaranteed Bit Rate): This parameter applies only to carriers GBR requiring guaranteed quality of service and voice service. • Maximum bit rate (MBR, Maximum Bit Rate): this parameter is set a limit for bit rates of services offered. • Class Identifier quality of service (QCI, Quality of Service Class Identifier) is used within the access network as a reference to a number of parameters that control the processing of packets through different network nodes. Each QCI is associated with a number of characteristics

QCI

Resource Type

Priority

PDB (ms) 1

PLR 2

Examples of services

13

2

100

10 -2

Conversational voice

23

4

1000

10 -3

Conversational video

3

50

10

43

5

300

10.6

Video not conversational

53

1

100

10.6

IMS Signaling

64

6

300

10.6

Video streaming, www, email, chat, ftp, p2p, etc.

7

3

3

GBR

Real-time Gaming

-3

7

100

10

85

8

300

10.6

Video streaming, www, email, chat, ftp, p2p, etc.

96

9

300

10.6

Video streaming, www, email, chat, ftp, p2p, etc.

3

Voice, video, interactive game

-3

No GBR

1 must be subtracted from a delay of 20 ms between the base station and PCEF to determinate the PDB that applies to the radio interface. This is an average of delay considering the cases in which the PCEF is close (approximately 10 ms) and which is far (about 50 ms). It should be noted that the PDB set an upper limit, so you should expect that delays are significantly lower, especially for GBR traffic.

2

Applies to the radio interface between the UE and the eNodeB.

3

associated with operator-controlled services.

can be used for prioritizing specific services according to the specification of the operator. 4

5

can be used to carry dedicated user or premium user groups with privileges.

6

carriers typically used for default unprivileged users.

Figure 90 - Specific features for the QCI

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• Resource type: determines whether the carrier is GBR or not RBM. • Priority: is used to differentiate the connections SDF. Each QCI is associated with a priority, with 1 being the highest priority. • Packet delay budget (PDB, Packet Delay Budget): refers to the possible latency of data packets transported between the terminal and the PDN-GW. This is the same for the downlink and up to one QCI. • Packet loss rate (PLR Packet Loss Ratio): describes the maximum rate of packets transmitted to the upper layer of all packets processed by the link layer. Like the PDB is the same for the uplink and downlink for the same QCI. • In addition to the carrier level parameters, there is a parameter of quality of service associated with the terminal called maximum aggregate bit rate (AMBR, Aggregate Maximum Bit Rate) which applies only to non-GBR bearers. Serves to limit the bit rate of subscribers differently, it is also defined but not for a carrier to a carrier group of a subscriber

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7.3.4

Packet Filters

A packet filter has to be created in the PDN-GW (and signaled the EU) of each SDF in order to allow proper allocation of the data in the EPS bearer channel and correct routing. The EPS bearer channel is associated with a TFT (one on one in the UL and DL) and therefore an EPS bearer channel can carry only one SDF, while all data from the same EPS bearer experience the same QoS. The SDF can be assigned a same carrier EPS only if they have the same QCI and ARP. The packet filters are sequentially applied to the input data (in the EU in UL and DL in the PDN GW) according to values of packet filters in the Index-Evaluation-Priority. If the data do not match should be sent to the carrier that has no associated packet filters. If no such carrier data must be returned. The packet filter package has a unique identifier (1-8) in the TFT and consists of one or more of the following attributes in terms of its configuration with respect to the application that entail: • Source / Destination IP address subnet mask • Number of protocol overhead (eg, TCP / UDP) • Destination port range. • Source port range. • Index IPSec security parameter. • Service type, identifies the quality of service • Flow level, only used for IPv6

7.3.5

Mapping the QoS parameters for UMTS and EPS

Since its beginning in LTE / SAE will have to live with 2G/GPRS and 3G/UMTS networks, it is necessary to map the parameters between networks as they are distinct together. The following figure summarizes the mapping between parameters.

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PDP R97/98

PDP R99

EPS R8

Delay

Traffic Class

Carrier Type

Priority traffic management

Reliability

SDU Error Rate

PLR

Bit error rate residual Delivery of erroneous SDU

Peak transfer rate

Maximum bit rate for uplink

MBR

Maximum bit rate for downlink

Precedence

ARP

ARP

Average transfer rate

N/A

N/A

N/A

Maximum SDU size

N/A

N/A

Transfer delay

PDB

N/A

GBR

GBR

N/A

N/A

AMBR

Figure 91 - Mapping of QoS parameters for UMTS and EPS

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7.4

Implementing a solution SON (Self Optimizing Network) to support efficiency

This section identifies two important measures that the telecommunications operator should take into account when deciding to migrate from one network GSM-UMTS to LTE. The first one is to increase automation in the management of radio access network and the second concerns as to efficiently activate new subscribers. The mobile telecommunications industry is developing LTE to support a wide variety of applications requiring high data rates and signaling requirements resulting in robust quality of service (QoS). The implementation of a large number of base stations (eNBs) Femtocells known as Home-eNBs is within a highly complex since it combines a number of parameters that must be put in place and to ensure interoperability. One of the main specifications created by the International TR36.902 3GPP is indicated regarding the Self-Optimizing Networks (SONs). The Sons automatically configure and optimize networks in order to minimize operating costs. SONs displays the interaction between base stations and connecting them with the Core Network, with the aim of improving the functions of embedded optimization. The three main features of SON are: self-configuration, self optimization and self-healing.

7.5

Reuse of access equipment

It is always advisable to install antennas and feeders separately when installing new technologies. This recommendation maximizes system performance, minimizing the impact on existing systems, eliminating the interaction during the optimization of the network, minimizing interference and simplifies the tasks of Operation, Administration and Maintenance (OA&M). However, mobile operators 2G and 3G are looking to install multiple antennas at each base station, because the sites where these antennas are usually installed rentals and permit application required for the installation of the same and this means high costs. Therefore, making sharing of antennas located at a base station BTS can save time and money. This technique can be divided into two main categories: Multi-Band and Co-Band. Mobile phone operators 2G-3G most likely be using both techniques to combine

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GSM and UMTS. This could complicate the purposes of implementing the same site antennas for the new LTE technology. • Multi-band technique: Techniques for Multi-Band combines the signals received and transmitted from different base stations operating in different frequency bands. • Technical Co-band: The Co-Band techniques combines the signals received and transmitted from different base stations operating in the same frequency bands. For its part, must take into account the shared antenna systems, share patterns and coverage antennas, this means that an adjustment in these antennas to optimize the system could affect the operation of the entire system of sharing the antennas.

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7.6

Reuse and improvement of network backbone and backhaul transport

Here arises an important question, “Are you ready to decant cellular operators in their networks exponential growth in data traffic?” The answer is no, because in general their transport networks (backhaul) are based on technologies and protocols that were designed for voice traffic. Importantly, the backhaul network is connecting access nodes to the backbone IP network.

Figure 92 - Backhaul Backbone and IP

The data transmission networks of the operators will have to reach eventually migrate to new technologies, which allow the growth of data traffic while maintaining the profitability of operators. This challenge can only be achieved with a transport architecture that is efficient in data traffic, and that has a wide possibility of scalability.

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Do not forget also that the demand for voice services continues to grow, and network traffic increases not only the data but in the traditional services. Thus, it imposes a greater need to free up capacity on legacy networks, and to accommodate data traffic in the infrastructure of next generation based on IP / Ethernet that allows for growth by increasing costs marginally, to introduce technologies such as HSPA+ and LTE. Among the major requirements to be met by a backhaul network to support LTE are: • Increased capacity: 100 Mbps exceed its deployment • Low Latency: must meet requirements of 10 ms for point to point • Improved services: should point to point interface (S1) and multipoint interface (X2) efficiently • Support services and legacy equipment Moreover in the industry are shuffled some figures regarding the ability of each technology required for transport: • HSPA supports 50 Mbps per sector • HSPA+ up to 100 Mbps per sector • LTE will support up to 170 Mbps per sector More details of the Japanese manufacturer Fujitsu suggests that the capacity required per site is only the spectrum (channel size) available by the operator multiplied by the spectral efficiency of the air interface. The following figure summarizes these requirements for various wireless access technologies.

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Voice Data Spectral Spectral Efficiency (bit Efficiency (bit / Hz) / Hz)

Technology

Vocal Spectrum (MHz)

Spectrum data (MHz)

Sectors

% Utilization

Required capacity (Mbps)

Number of E1s

2G GSM

1.2

-

0.52

-

3

70%

1.3

1

GSM / EDGE 2.75G

1.2

2-3

0.52

1

3

70%

6.1

4

3G HSDPA

-

5

-

2

3

70%

21.0

14

LTE

-

5

-

3.8

3

70%

39.9

N/A

LTE

-

10

-

3.8

3

70%

79.8

N/A

Figure 93 - Requirements for mobile network capacity

As shown, for a site with 3 sectors and a 5 MHz channel capacity will require about 40 Mbps, while for a 10 MHz channel will be 80 Mbps and thus the requirement will increase to reach 20 MHz channel that supports LTE.

7.6.1

Evolution LTE backhaul

Today the vast majority of operators have to transport TDM voice and data backhaul. The option to keep adding E1 to provide more capacity becomes immediately feasible, since it would require a disproportionate amount of them to support traffic growth is anticipated in the future. Fortunately, industry and operators have identified the technologies to start migrating their transport networks in order to accommodate the growing traffic. The future of transport networks of cellular operators offer goes through the Ethernetbased services and transport networks based on IP / MPLS and Carrier Ethernet, which lived for several years with the networks eventually replaced, as TDM, ATM, SDH / SONET and Frame Relay, which have been used to carry voice traffic and data over E1 connections, mainly. In fact, the convergence of transportation costs needed to manage these services do not increase proportionally to use, has caused the Broadband Forum, which took over the IP / MPLS Forum-unite with the Metro Ethernet Forum ( MEF) for IP / MPLS

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to offer Carrier Ethernet services. It seems that in future transport networks accounting is themselves with a portion in the core IP / MPLS and other nearby base stations, based on Carrier Class Ethernet, which has attributes conducive to cellular backhaul, as for example: • Standardized services • Scalability • Quality of service • Reliability • Service Management The dilemma of the operators is, therefore, how to perform this migration while respecting the existing services that now account for most of the income, while preparing its transport network to evolve its offering of data according to the expected growth is projected for the next three to four years. For operators with large investments in TDM migration route is more feasible coexistence, at least initially, TDM to Ethernet networks, where networks would handle all existing TDM voice traffic while the data stream is transported over Ethernet . And is that even though it might seem that managing two networks simultaneously affects a high OPEX for the operators, the costs would be comparatively lower than more input E1 lines for greater data capacity. And in the future transport networks will necessarily migrate to data transmission networks where Carrier Ethernet and IP / MPLS current bets seem to offer Ethernetbased services and emulate those based on legacy technologies. Strategically, cellular backhaul over Ethernet allows not only to offer services HSPA today, but leaves the transportation network ready for launch of HSPA+ and, above all, LTE which is an IP network from end to end and whose base stations have only Ethernet interfaces for transport tasks from the base station to the core of the operator's network.

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7.6.2

Transport backhaul technologies LTE

To meet the transport capacity growing demand, the following technologies are evaluated, backhaul fiber and microwave backhaul ranges 6-38GHz and 60-80 GHz.

7.6.2.1

Optical fiber

Fiber is technically very good complement to the backhaul. With systems that can easily scale it beyond 10 Gbps, the fiber will solve any problem that may have operators in terms of capacity requirements. The fiber can be deployed in redundant ring topologies, high-capacity but the infrastructure to do so can significantly increase costs. Finally, the fiber is capable of Synchronous Ethernet allowing the management of multiple service levels and providing synchronization LTE. Given these capabilities, if the fiber has already been deployed and is available, is the perfect option for LTE backhaul.

7.6.2.2

Microwave

Traditionally, microwave (range 6-38GHz) have capacity constraints in a range between 150 and 300 Mbps, however, with new technological advances in the microwave field may give more than 1 Gbps and some systems up to 4 Gbps. There are still many versions of microwave systems available, with packages based on microwave technology commonly used for backhaul. For its part emerging microwave products are offered to distribute synchronization capabilities for LTE base stations. Also, some of them are equipped with ring exchange capacity, ie allowing to set different ring architectures dynamically, with service capabilities high end performance.

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7.6.2.3

Millimeter Wave Technology

Recently, some operators have begun to evaluate millimeter wave technologies for 4G backhaul. These products can generally meet the requirements of 4G capacity when most systems reach only 1 Gbps capacity. Many of these systems prioritization so that they can be multiple levels of service. 60-80 GHz systems do not currently provide Synchronous Ethernet capabilities but it is assumed that they probably will because the LTE deployments require. In economic terms, the costs of 60-80 GHz are quite similar to those of 6-38 GHz microwave On the other hand, the greatest challenge millimeter wave systems is its availability and the resulting range of capabilities due to rain fade. Because these litters are at millimeter wave frequencies as high, are very susceptible to rain, resulting in limited sections of link in order to achieve reasonable capacity. It is also limited to less than two miles stretches. Then noticed that there are several viable options to meet the requirements of backhaul and access networks is predicted, LTE network will use any one technology. Certainly there will be a mixture of two or more optimal network technologies driven by the location of the site and distribution sites. For new construction sites that require miles of range, shows a typical preference for microwave technology from the perspective of cost and accessibility. However, in a large network find fiber in the central area where very high capacities are required and may be some millimeter wave technology in sectors where the scope permits.

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7.7

Summary of proposed technical requirements for deploying LTE

In general we could say that if an operator want to evolve their existing networks to LTE, changes in these networks consider switching at the hardware level (additions and / or upgrades), software (upgrade or update), or hardware and software at a time. This can occur in both radio access network as the core of the network. 3G/LTE Network basically consist of: • Radio Access Network 3G/LTE - RAN (Radio Access Network) • Packet Switched Network - CNPS (Core Network Packet Switching). • IP Transmission System for Fiber Optics • Support System O&M for each of the three previous items

7.7.1

Frequency bands for equipment

The operator is responsible for the suitability of spectrum for operation of GSM, UMTS, HSPA+ and LTE. For example, the working frequency of the equipment for LTE (FDD and TDD) may be any of the following frequency bands: • 2100 MHz (1920-1980/2110-2170) • 1800 MHz (1710-1785 / 1805-1880 MHz) • 850 MHz (824-849/869-894) • 700 MHz in the case of release of the Analog TV spectrum in this band.

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7.7.2

Modifications to the data network

• The system should include all elements of hardware and software for the operation of the data, with the latest revision of UMTS/HSPA+ & LTE, both CNPS data backbone (Core Packet Switching Network,), as in the base stations ( Node B) and the RNC (radio network controllers).It should allow the operation of this network to UMTS / HSPA / HSPA+ & LTE data mode with the latest versions of available terminals. • There should be no hardware or software limitations on the nodes of the system to prevent the use of all data features adopted by the 3GPP to date in making the network implementation. In this sense, should be included every element of network-level hardware (HW) and software (SW) considered necessary for the proper functioning of the system. • Integration should include physical and logical level of all elements of the 3G/LTE network with the current GSM network. To this effect should consider all logical interfaces required for such integration, as well as with regard to physical integration. • The system to be implemented to allow for the coexistence of UMTS, HSPA, HSPA+ and LTE. It is important to mention that the 3G NodeB should have changes at the HW and SW (upgrade) for it to support LTE and their respective protocols. • A Packet Switched Network (CNPS) for UMTS, HSPA+ / LTE 3GPP Release 7 and 8, which must comply with the technical specifications, among many others at least should include, the following items : o A Serving GPRS Support Node (SGSN) R 7 and 8. o A Gateway GPRS Support Node (GGSN) R 7 and 8. o SAE Gateway architecture (SAE / LTE). o MME architecture (SAE / LTE). o HSS.

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7.7.3

Technical Requirements multistandard base stations (UMTS/ HSPA +/ LTE)

It should be noted that the migration of existing UMTS-HSPA towards LTE technology, is considering the possibility of reusing existing base stations equipped with technology SDR (Software Defined Radio).This technology allows the use of a common hardware platform capable of supporting different radio interfaces (GSM, UMTS and LTE) through a software update. Both are defined by at least the following requirements: • Type outdoor base stations and also distributed multistandard UMTS / HSPA / LTE. • In each radio base should be able to insert modules UMTS/HSPA+ and LTE in the same cabin or cabinet. Initially, the base stations will be equipped with UMTS/HSPA+. • The base station should enable the joint operation of UMTS and LTE, with an efficient and optimized transport, synchronization, energy and management. • Nodes B and RRU for UMTS must comply with the recommendations and subsequent developments Release R7 (R8, etc.). • The RRU eNode B and LTE must comply with the recommendations and subsequent developments Release R8 (R9, R10, etc.). • Based on the foregoing, the Node B must be enabled to HSPA + functionalities and other features of this Release (eg Iu-PS and Iu-CS over IP). • The base stations must support a minimum of 3 sectors. • It is up to each network provider the amount of RRU that will be needed by industry. • LTE should be able to allow for the use of MIMO antennas (2x2 and 4x4) in both Rx and Tx. • The base stations must withstand operation in the bands allocated to LTE. • All base stations should have the following characteristics: o Integration with the system operator "All IP" as well as backhaul interfaces Fast Ethernet to support UMTS / HSPA / LTE o Base Stations must be able to logically separate voice and data traffic in different VPNs: a) VPN for voice traffic of UMTS / HSPA + (interface lub-CS).

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b) VPN data traffic for UMTS / HSPA + (Iub interface-PS) c) VPN traffic from one eNodeB to another eNodeB LTE Interface (X2) d) VPN traffic to a eNodeB LTE MME interface (S1) e) VPN traffic from one eNodeB to LTE-SAE GW (S1-U interface) These VPN must be multiplexed onto the same physical interface, or Fast-Ethernet interface the minimum amount possible. • The base stations should support the following types of services, details of which shall specify: o CS Domain Services (voice and data transparent and not transparent to different rates). o PS Domain Services. o Combined services (voice, data services in the CS domain, domain data services in PS). o Location Services handovers (Softer, Soft and Hard, including bidirectional handover 2G-3G and 3G-4G). o Access technology of the E-UTRA (base stations) to LTE will be full duplex FDD. o LTE should be possible to use flexible bandwidths from 1.25 MHz to 20 MHz. o In the downlink, OFDMA and 64QAM modulation schemes, 16QAM and QPSK. o In the uplink SC-FDMA and BPSK modulation schemes, QPSK, 8PSK and 16QAM.

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7.7.4

Technical requirements of the Radio Network Controller (RNC)

• The RNC is the component of the UMTS network responsible for controlling the Node Bs (base stations) via the Iub interface. • The equipment manufacturer should describe the various architectures and EUTRAN supported by their equipment, but shall at least comply with the reference architecture. • The manufacturer shall provide all the technical facilities of the RAN (Radio Access Network UMTS, HSPA+ and LTE).Here are some of the most important. The folling table depicts “Facilities RAN techniques“.

Facility

RAN

Assignment dynamics resources

Dynamic resource allocation of hardware and software according to the QoS requested by UMTS, HSPA+ and LTE the EU and the burden of the various elements of the system.

QoS classes

The system must support the four service classes defined by 3GPP (conversational, UMTS, HSPA+ and LTE streaming, interactive, background)

Control overload

Faced with massive access attempt phones, should provide mechanisms to ensure that UMTS, HSPA+ and LTE these efforts do not destabilize the operation of the RAN.

EU Location

Shall provide software functionality that allows the location of DU LBS for UMTS UMTS, HSPA+ and LTE HSPA and LTE similar

SMS point to point

SMS broadcast Point to point

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Description

Ability to send from alphanumeric messages

/

to

a

mobile

UMTS, HSPA+ and LTE

Possibility of sending an SMS while all subscribers registered in a number of sectors UMTS, HSPA+ and LTE to be defined. Ability to send / receive MMS in EU

UMTS, HSPA+ and LTE

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MMS MMS broadcast

Possibility of sending an MMS while all EU UMTS, HSPA+ and LTE registered in a given set of cells

Call Emergency

It should be possible to assign higher priority to emergency calls (to numbers prefixed) UMTS, HSPA+ and LTE compared to the rest of the calls originated. CS applies to Voice and VoIP.

Reconfiguration Automatic Channels logical

Automatic channels

reconfiguration

of

the

logical

UMTS, HSPA+ and LTE

Control power

Initial control and dynamic power transmitted by the Node B and the EU in all its forms, and UMTS, HSPA+ and LTE uplink and downlink.

Efficient use resources sectors and / or Node B

Faced with a lack of resources in a sector and / or Node B (number of codes, power, processing power, transmission, etc.), The system should allow the redirection of calls to UMTS, HSPA+ and LTE other sectors and / or Node B same or different carrier. This procedure should act when attempting to establish the service and during the course of a communication.

Handover intra

ENodeB Intra, Inter eNodeB, with different MME eNodeB Inter, Inter MME eNodeB the same but different SAE GW, Inter RAT (Radio Access Technology).

LTE

Handover intersystem

It should allow two-way handover between UMTS, HSPA+ and LTE UMTS, HSPA+ and LTE

Mechanisms reselection sectors

By parameterized algorithms would allow the EU camp in areas that at first would not be UMTS, HSPA+ and LTE the best server (Sector Hierarchy)

Scheduling

Dynamic allocation of EU resources to uplink UMTS, HSPA+ and LTE and downlink.

Compression and IP header compression and encryption of UMTS, HSPA+ and LTE IP Encryption user data

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Physical Access FDD

FDD for paired spectrum. Downlink in different frequency

Physical Access TDD

TDD mode for unpaired spectrum. Uplink and Downlink at the same frequency, whose plots met delays of no more than 10ms.

LTE

Physical Access FDD and TDD

FDD and TDD physical access to the same base.

LTE

Configuration. common

Simultaneous configuration of common parameters for associated eNodeB

LTE

Modulation LTE

Downlink: OFDMA: 64 QAM, 16QAM and QPSK. Uplink: SC-FDMA 16QAM, 8PSK, QPSK, BPSK

LTE

VoIP

Voice over IP protocol with less delay

Handover to WLAN

7.7.5

Uplink

and

LTE

UMTS, HSPA+ and LTE

Relayed directions between Wireless Access UMTS, HSPA+ and LTE networks and non-3GPP 3GPP.

Technical characteristics of the packet core

For the implementation of a Packet Switched Network (PS-CN, Packet Switched Core Network) UMTS-HSPA+ and SAE / LTE recommends: • The system (ie the set of nodes and packet core functionality) should be designed such that it can join other Next Generation Networks (NGN), enabling further expansion of its capacity later. • Includes the acquisition of Gateway SAE / LTE, MME and HSS. As for the reference architecture is depicted below a generic block diagram of the wireless network, which includes the nodes of the architecture and the interfaces involved. Each interface must be considered both from the standpoint of physical and logical. Blocks and interfaces that are illustrated in the following figure, should be taken as reference, where necessary, for submission of the required information.

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Figure 94 - Proposed system architecture for LTE

This system then must support access 3G and LTE. The system offered by each operator must ensure the compatibility of its components with the future implementation of functionality as the IMS architecture.

7.7.6

Technical characteristics of interfaces

• The system must support the following quoted logical interfaces defined by the 3GPP standard: Iu, Gr, Gs, Gd, Ge, Gf, Lg, Gc, Gn / Gp, Ga, Gi, interfaces for LTE (S1-MME, S1-U , S3, S4, S5, S6A, S7, S8a, S10, S11, SGI, Rx) and other interfaces required to implement the architecture referred. Physical interfaces must be optical, or optical-electrical connections for Fast Ethernet and Giga Ethernet. SS7 signaling is over-IP (SIGTRAN). • All interfaces shall comply with the specifications: TS 29002, TS 29016, TS 29.018, TS 29.078, TS 29.060, TS 29.061, TS 32.015, TS 32.215 and all connected by them.

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7.7.7

Core Specifications SAE / LTE

• Support for multiple types of access: LTE, HSPA, HSPA + and non access technologies standardized by the 3GPP. • Must support air interfaces LTE as well as roaming and mobility between LTE and UTRAN / GERAN: S1-MME, S1-U, S3, S4, S5, S6A, S7, S8a, S10, S11, SGI, Rx +, etc. • Must support interfaces and standards for access to technologies standardized by the 3GPP, S2a, S2b, S2C, S6C, S6d, S9, SWA, SWD, SWN, SWX, SWU and STa. • Support for Quality of Service (QoS).

7.7.8

MME techniques features

This node control plane, handles the control signaling for mobility between 3GPP networks and manage identification and security parameters of the EU. The MME shall perform the following functions: • Selection of Serving Gateway and the PDN Gateway. • Selection of MME to MME handovers with others. • SGSN selection for handovers to access networks 2G or 3G. • Facilitate roaming between access networks.

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7.7.9

Technical specifications of SAE Gateway

The SAE Gateway consists of two logical entities of the user plane the S-GW and the PDN-GW serving as interfaces between Access Network and the various packet networks. These logical entities can be implemented as a single element Network.

7.7.9.1

Serving Gateway (S-GW)

Is the node responsible for E-UTRAN termination. Serving GW functionalities are: • Mobility Management handover between eNodeB. • Mobility management for handover between 3GPP LTE and other technologies. • Transmission and routing of packets.

7.7.9.2

PDN Gateway

Is the node to be made by the end of the SGI interface to the PDN. The functionality of the PDN GW should be: • Seamless mobility management and continuity of user sessions when moving between technologically heterogeneous access networks (aligned and not aligned with the 3GPP). • Application of QoS policies. • Packet filtering user. • Support charging for traffic between PCRF and the PDN-GW. • Location UE's IP address.

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7.7.9.3

HSS Home Subscriber Server

The HSS is the database of subscribers converged LTE, which will be recorded and audited profiles and devices, and will support future network deployments "All IP". Must support open standards allowing full interoperability vulnerability to the elements of multi-vendor network. The HSS shall administer: • The identities of subscribers and services. • Service profiles. • Authentication. • Authorization. • QoS for Long Term Evolution (LTE) and IP Multimedia Subsystem (IMS). Shall comply fully with the 3GPP Release 8, to environments multi-vendor interoperability, these should include standardized interfaces LTE: S6A (towards MME) S6d (towards SGSN), SWx (towards 3GPP AAA), IMS interfaces (Sh, Cx). Other features are: • Support for Locating Subscribers (Dx, Dh, Dw). • 3GPP AAA support for interoperation with non-3GPP networks, reliable and unreliable. • Must support seamless mobility features, and portability of services across IP networks. • Flexibility to support multimedia services. • Database Subscriber Profile converged HLR / HSS.

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7.7.10

Technical management of the system

The architecture of SGSN, GGSN, MME, SAE GW, HSS and other items should have the role of OAM (Operation Administration and Maintenance), which will be responsible for collecting data (alarms, statistics system HW and SW ), management and user control of the control tasks of HW and SW, etc.

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8

LTE Business Perspectives

The following are important aspects that allow for a comprehensive overview for anyone interested in implementing operator LTE technology. These aspects indicate a growing trend in the consumption data from mobile terminals existing today. Also, are some commercial LTE equipment that already exist in the market with the aim of which is evaluated by the operators that choose to implement this technology forward. Finally it includes the case of LTE network deployment made by the operator Teliasonera, with the aim to indicate that the use and marketing of services using these networks today is a reality.

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8.1

Global trend in demand for data

The mobile broadband connection is one way that the user can access the Internet wirelessly from anywhere you are. The following figure shows an estimate of the behavior of global demand in recent years have had the voice and data services, with a decrease in voice service revenues and an increase in revenue due to the demand for services data.

Figure 95 - ARPU by traffic type, b) Revenue by type of traffic

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The overall market trend has been perceived by operators such as AT & T, Orange, Vodafone, Telefonica, Vivo and Telstra as shown bellow.

Figure 96 - Wireless markets revenues increased tendency

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In relation to the above, some predictions indicate a steady growth of users who make use of a large number of devices to connect to mobile networks.

Figure 97 - Wideband subscribers to mobile-device type

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In this connection, the user is expected that greater use of adaptive devices to personal computers (such as data cards) for wireless access to applications and data services.

Figure 98 - Traffic subscribers in mobile access networks

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8.2

LTE as a data access solution

It is expected that the introduction of this technology to market operators have benefits such as reduced costs as CAPEX and OPEX. In turn, because LTE is focused on facilitating access to new data services and better rates, it is estimated that it allows an increase in revenue for the operator.

Figure 99 - Market trends in mobile broadband

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For their part, some other aspirations and needs as displayed with LTE operators are listed in the following figure.

Aspirations of operators to deploy LTE Feature

Potential Impact

Justification

ARPU

Services and value-added applications Revenue from new services Proliferation of broadband devices

CCPU

All-IP networks Backhaul Network Virtualization Migration, multiple networks, OSSS, etc.

Customer retention time

CPGA

Subscribers

CAPEX

New applications 4G More devices per user New payment without contracts Economy of scale Customer acquisition. Best subsidies. New applications for new market segments Higher bandwidths, aimed to improve performance More devices with mobile broadband capability Economy of scale All-IP networks and spectrum efficiency. Network Virtualization Multiple networks in transition.

Figure 100 - Aspirations market operators including LTE

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8.3

Operators Initiatives

Today we already have confirmed more than 50 operators committed to LTE in the coming years. The following figure shows an overview of the operators committed to this initiative.

Figure 101 - Project operators committed to the LTE / EPC

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To complement this, bellow, depicted with red markers are countries where operators committed to deploying LTE in the coming years. For its part, the blue markers represent das networks deployed by the operator TeliaSonera in the countries of Sweden and Norway.

Figure 102 - Map of countries with operators committed to deploy LTE networks

With regard to these deployments, one of the great unknowns in relation to LTE is about why some traders are choosing to invest and deploy LTE immediately, while others have adopted more than a stance of "wait and see what happens." One explanation is that the resources of the spectrum that the operators have determined the technology and time of release. In Europe, for example, many operators are strongly committed to LTE will have to wait for the spectrum to be auctioned, especially in the 2.6GHz band. Operators such as Telecom Italia and Vodafone UK are laying the groundwork to deploy LTE, but until the spectrum is released, it is difficult to anticipate the time of release of LTE. For its part, the key band in the U.S. for LTE, is 700 MHz, while the 2.1 GHz band will be more frequent in China and Japan. Another explanation is the difference between CDMA and UMTS. Operators with CDMA networks - technology that has no next evolutionary stage in their 3G platform - are migrating directly to 4G, while operators with UMTS networks have many phases of development ahead for their HSPA networks. AT&T for example, seems to have no urgency to deploy LTE, because the operator has been adding thousands of sites, antennas, towers, backhaul connection, etc., To support high broadband speeds offered through its HSPA network. For AT&T, LTE will add more capacity and

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bandwidth to meet the growing demand for data services. However, the operator plans to continue developing HSPA speeds increase to 14.4Mbps (now offers a speed of 7.2 Mbps), then migrate to HSPA+ and finally launch an LTE network in 2012. This means that for some operators to migrate to LTE will be simpler than others. For example, operators have already launched a 3G network, will require an upgrade of its network ahead of its evolution. Moreover, as shown bellow, two of the main reasons why operators are investing in technology is the need to offer new services to meet user expectations and the possibility of reusing existing 3G infrastructure.

Figure 103 - Main reasons why operators are investing in LTE

Addition, as mentioned above, the evolution to LTE is attractive to many operators because it reduces the CAPEX and OPEX compared to legacy technologies such as 3G networks. In fact, a report published by the UMTS Forum indicates that the cost per megabyte for LTE services will be 83% lower with respect to (W-CDMA) and 66% lower compared to HSDPA.

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8.3.1

Operators in Asia

In Asia, NTT DoCoMo in Japan is an operator that has been very active with respect to LTE, driven by demand for high-speed data services in the country and the company's commitment to implement cutting-edge technologies quickly. This operator has tested at speeds of 250 Mbps in the downlink and 50 Mbps uplink using 4x4 MIMO technology. These tests were performed at frequencies of 1.7 GHz in a bandwidth of 20 MHz, respectively. For these tests are used equipments from manufacturer Fujitsu. NTT DoCoMo plans to launch a commercial LTE network in December 2010, and in principle, only be accessible via USB modems for personal computers. For the year 2011, would begin selling phones to offer dual LTE/3G national coverage that users acquire, and a quick solution for the supply of voice and SMS services on these devices. China Mobile for its part, has actively participated in LTE trials with vendors. The company has announced for mid-2010 plans to build a commercial pre LTE TDD network in China and continue the testing stages at the end of this year.

8.3.2

Operators in Europe

In Europe, the operator TeliaSonera LTE deployed in Norway and Sweden and this has had the support of the company Ericsson and Nokia Siemens Networks. Another operator is Telefónica (Spain), which has tested getting data download speeds in excess of 140 Mbps will soon begin installation of LTE base stations to conduct pilot tests, which the operator expects to reach speeds Download up to 340 Mbps pilot project conducted in collaboration with manufacturers such as AlcatelLucent, Ericsson, Huawei, NEC, Nokia Siemens Networks and ZTE. Other European operators like Vodafone have been tested in Europe with technology supplied by Ericsson, Huawei and Qualcomm Inc., hoping to start selling services over LTE networks between 2011 and 2012.

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8.3.3

Operators in Latin America and the United States

Many operators in the region (Telefónica Chile, Movistar, etc.), use in parallel different technologies such as UMTS with GSM. According to experts who gathered at the conference LTE Latin America 2010 held in Brazil, LTE cannot be deployed as a traditional network. In Latin America until recently, the vast majority of operators deployed their 3G networks, as LTE is an issue that is just beginning to arise. Inclusive, some operators are evaluating the possibility to migrate first HSPA + and thereby delay the deployment to LTE. The following figure shows different scenarios that operators continue to migrate to LTE.

Figure 104 - Plans evolutionary operators around the world

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It is expected that in 2012 made the first official release of LTE in Latin America, and why would delay which could be mainly due to spectral problems, experts say. Also expected to make many trials and tests in 2010 and 2011. Operators such as Entel PCS (Chile) could provide technical and LTE, but for the same reasons of spectrum is not possible to do today. In Costa Rica, ICE assistant manager of telecommunications, Claudio Bermudez, announced in March 2010 that the institution is preparing a development plan for 2015, where he is studying the proposal for LTE as well as mobile WiMAX.

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8.4

Initiatives manufacturers

In this section shows some terminals and LTE network equipment already available in the market.

8.4.1

Network Equipment

Today, several equipment manufacturers and mobile networks are in some network equipment market for this technology, other manufacturers are still under design and test stages. Here are some of the major manufacturers and their network equipment proposed for LTE.

8.4.1.1

Huawei

Huawei is one manufacturer that offers a solution that allows you to deploy an LTE network without the need to have legacy infrastructure to other mobile networks, it also allows migration from networks such as WCDMA. This solution includes terminals, access network, transmission network SAE and unified management of the network. The solution proposed by this manufacturer and emphasizes the simplicity of the network, since it combines elements such as SGSN, AG, MME in a single node called unified service node. Also joining the GGSN, PDSN, ASN-GW, PDG, S-GW and PDN-GW in a single node called Unified Gateway. With respect to the nodes B, they are composed of a remote radio unit (RRU, Remote Radio Unit) which is installed near the antenna, and the base band unit (BBU Band Base Units), both teams are interconnected by fiber optic cables. To migrate from a node B to HSPA+, it’s necessary to upgrade the software on computers RRU and BBU. To migrate an RRU configured to HSPA + to LTE at the same frequency band, also due to a software upgrade, however if you use a different frequency should change the team by adding a new LTE RRU. In the case of the BBU, to migrate a card adds LTE (LTE Card) to your computer. The migration process is shown in bellow.

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Figure 105 - Migration process from a Node B UMTS Huawei HSDPA to LTE.

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Today, Huawei offers an evolved Node B called NBS, which support multiple radio access technologies (GSM, UMTS, CDMA, TD-SCDMA and LTE).This commercial version is known as DBS3900 and is shown bellow:

Figure 106 - DBS3900 Huawei Base Station.

Each of these nodes consists of an indoor unit RRU and BBU model 3201 model 3900. The unit supports up to 3000 users per eNodeB, in the downlink can achieve 173Mbps with a 2x2 MIMO configuration, 64 QAM modulation and a bandwidth of 20 MHz, while in the uplink can reach 84 Mbps with 1x2 SIMO, 64 QAM at 20 MHz per cell.

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8.4.1.2

Motorola

The Motorola solution includes core network equipment (CPE) and access (EUTRAN). For the access network equipment manufactured WBR series 500 and 700, which are only eNodeB LTE equipment from Motorola. These support FDD and TDD bands 700, 800, 900, 1800, 2100, 2300 and 2600 MHz, and a variety of bandwidths ranging from 1.4 MHz to 20 MHz. The purpose of this manufacturer for the core network is based on the number of WBC 700 teams with mobility management entity (MME WBC 700), gateway packet data (WBG 700 P-GW) and service (WBG 700 S-GW), policies and billing (WBC 700 PCRF) and node management (WBM 700 Manager). The teams previously mentioned are shown bellow.

Equipment

Image

Description

MME WBC700

It also has a hardware acceleration platform designed to accelerate packet processing enabling high performance platform.

WBC 700 P-GW

High Performance Team, which integrates advanced services IP gateway security services such as deep packet inspection (DPI), stateful firewall, load capacity, and rapid mobility that allows mitigation of security.

WBC 700 S-GW

Is a router based on the integration of IP services with support for LTE Gateway functions.

WBR 500 LTE based RF Remote Macro eNodeB

Access equipment that uses OFDM and smart antennas. This equipment allows spectrally efficient, modular design that supports a wide variety of deployment scenarios

Figure 107 - Equipment Motorola LTE

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8.4.1.3

Nokia Siemens Networks

Nokia Siemens Networks has launched Nokia Flexi base stations (Flexi BTS), with the aim of providing the possibility of advancing technologies to 2G, 3G and LTE. Platform based on the Flexi base station, radio base extends the capabilities of its predecessor by incorporating GSM / EDGE, WCDMA / HSPA and LTE in a single device.

8.4.1.4

Ericsson

Ericsson has a range of equipment to deploy LTE networks, including the RBS 6000 series antennas, which are mobile phone masts are characterized by multi-standard and be prepared to cover both GSM / EDGE, and WCDMA / HSPA and LTE, it is compatible with previous generations of antenna.

Equipment

Image

Description

RBS 6000

The RBS 6000 series features a compact design, so it requires only 25 percent of the space occupied by previous generations of antennas. Despite its size, the RBS 6000 series has doubled its capacity, while reducing consumption by 20 to 65 percent over previous models. [48]

SGSN-MME

Provides access to 2G/3G/LTE, MME and SGSN QoS, Router etc. functionality.

Figure 108 - Equipment Ericsson LTE (I)

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Equipment

Gateway GPRS

Converged Packet Gateway

HSS and SAPC Server

Image

Description

Gateway GPRS which supports multi 2G/3G/LTE access, functionality MPG, throughput greater than 40 Gbps.

Converged Packet Gateway which provides access to 2G/3G/LTE, Release 7 and 8, extensive support for VPN, 200-Gbps throughput

HSS and SAPC server for centralized control of the IMS, can evolve in Release 7 to Release 8 supports up to 60 million subscribers per node.

Figure 109 - Equipment Ericsson LTE (II)

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8.4.1.5

NEC

This manufacturer offers a comprehensive network solution. It consists of an EPC system into one that incorporates all the MME, the S-GW and the PDN-GW. The EPC system is shown bellow.

Figure 110 - CORE compact network (EPC) for LTE

This system supports about 300 000 subscribers and can handle more than 100 base stations LTE. For its part, the solution for access network consists of units of baseband and radio frequency (BBU and RRU), also proposes the use of Femtocells LTE to offer better coverage indoors. NEC also offers the opportunity for a smooth migration from UMTS networks primarily by changes in the elements of network access.

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8.4.1.6

Fujitsu

LTE offers equipment for the access network (E-UTRAN) to the network core (EPC) as well as terminals. The products are offered under the brand BroadOne.

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8.4.2

User terminals

The trend indicates that the devices connected to 3G/4G networks will suffer a significant multiplication process in the coming years, with the proliferation of smart phones (smartphones), netbooks, laptops, smartbooks (hybrid between netbook and Smartphone) and all portable electronics. LTE is planned to start providing data devices such cards or USB modems. Bellow there is a summary of the terminals for LTE, which now have been announced by different manufacturers.

Manufacturer

Model

Device

Huawei

E398 LTE / GSM / HSPA 2.6 GHz, 900 MHz

USB modem

Samsung

GT-B3710 (2.6 GHz)

USB modem

LG

LD100

USB modem

LG

M13

Modem

Nokia

RD-3

USB modem

Samsung

N150 LTE chipset with Kalmia

Netbook

Samsung

GT-B3710 USB

Modem

Samsung

SCH - R900

Mobile Terminal

ZyXEL

ZLR-2070S

Router

Qualcomm

MDM9200, MSM8960

chipset

FourGee 3100/8200, 6150 Altair Semiconductor for TDD

chipset

ST-Ericsson

M700, M710

chipset

Infineon

LU SMARTi LTE/3G/2G Multimode RF Transceiver

chipset

Figure 111 - Device Manufacturers and models for LTE

Hereby some terminal characteristics mentioned above.

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8.4.2.1

LG

LG Electronics already have a modem chip for the technology and has implemented a data card called LD100 LTE that is capable of providing speeds up to 50 Mbps in the uplink and 100 Mbps download speed.

Figure 112 - LG LD100 terminal modem.

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For its part the terminal LG M13 is a dual device LTE / CDMA capable of operating in 700 MHz band. This terminal supports bandwidths of 5 and 10 MHz and is expected to have transfer rates of 70 Mbps in downlink and 20 Mbps in the uplink.

Figure 113 - LG modem M13 Terminal

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8.4.2.2

Samsung

For its part, Samsung has introduced a chipset called Kalmia LTE modem, which has enabled the creation of model Netbook N150 LTE connectivity.

Figure 114 - Netbooks N150 model

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Samsung also unveiled its SCH-R900 mobile terminal which is expected to be available in late 2010 and will operate with the operator MetroPCS in the United States will be able to LTE and CDMA.

Figure 115 - Terminal Samsung SCH - R900 and modem USBGT-B3710

Samsung also put into operation together with Telia Sonera the USB modem GTB3710 with downlink capacities of 150 Mbps

8.4.2.3

Motorola

The Motorola LTE terminal Tablet was unveiled at the Consumers Electronic Show (CES) in January 2010, running on a test network operator Verizon, who plans to deploy networks using this technology. The device runs on Google's Android platform, has a 7 inch touch screen, 32 GB of internal memory, Nvidia video chip and the Motorola LTE modem. If this device hits the market could do with an initial cost of $ 300

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8.4.2.4

Huawei

Huawei introduced at the beginning of 2010 the E398 modem. The E398 is the first modem LTE of this company with triple-mode is compatible with LTE, UMTS and GSM.

Figure 116 - LTE Modem Huawei

8.4.2.5

Nokia

Nokia also introduced its LTE modem DR-3. The modem DR-3 also supports interoperability with GSM / EDGE and WCDMA / HSPA. On Nokia devices there is little information yet available.

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8.4.2.6

ST-Ericsson

ST-Ericsson showed its M710 chipset which has interoperability between LTE and HSPA networks, with this the company showed download speeds of 100 Mbps and 50 Mbps upload. Its main features are provided by the manufacturer: • Multi-mode LTE / HSPA / EDGE • Capacity of 100 Mbps in download, 50 Mbps on the rise • LTE UE Class 3 • Quad band LTE • Tri-band WCDMA • GPRS / EDGE quad band band • Supports bandwidths of 1.4, 3, 5, 10, 15, 20 MHz • LTE MIMO • High Speed USB 2.0 • USB Ethernet for data access

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8.4.3

Expectations and needs of end users

End users can now enjoy the mobile broadband from their laptops and netbooks as well as from their mobile phones. Therefore, to provide an improved user experience is essential and which devices can provide intuitive interfaces and unlimited access to content and applications of particular interest. For this reason, the introduction of high capacity mobile devices such as iPhone, have boosted mobile broadband, which is increasingly being used as a substitute for fixed broadband. However, the availability of high quality content, including audio and video, has led to a significant increase in data traffic. Consistent with this, is expected to increase six times in the global IP traffic between 2007 and 2012 (mainly driven by video services), which will have an impact on mobile networks and fixed networks. This projected growth justifies the view of operators for LTE technology for mobile broadband.

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8.4.4

New services can be provided with LTE

The primary objective of deploying LTE technology is that by far exceed the capabilities offered by today's 2G and 3G. Following are a series of new services or improvements to them that the operator would be able to provide to Technology LTE. The following table depicts the mobile services that offered by LTE.

Enabled services and improved over LTE Technology Sector

LTE Ecosystem Components / features in the service applications and devices

Consumer Services

Devices and user interfaces and servicespecific applications

* Innovation in all * Innovative services for multiple components: operating market segments. system (OS), protocols, processors, antennas, batteries, multi-touch screens. * Interactive interfaces. * User-friendly services. * Open platforms which allow new applications, services, content, portals access. * New terminal for narrowband and broadband markets.

The Internet

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* All that provides Web 2.0: Communication, interoperability, sharing, collaboration large databases for consumers and the product marketing.

* Social networking. * Share photos, video and music. * Access to blogs, news, chat, games, travel information, communities and interest groups. * Internet TV, Streaming and Downloading Personalized and location.

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Navigation and Location

* GPS and location services per cell * Geographic Information Services (GIS * Directory services to store and organize information of network users.

* Content based on location *Access to location information and presence of contacts *Shopping and sections of products from mobile terminal according to location * Mobile access to the itineraries of travel agencies.

Transportation

Banking

* Vehicle manufacturers * Government agencies. * Entertainment systems in automobiles. Chipsets and devices to measure. * Service centers for mobile applications. * Content providers Radio and television services adapted for use in vehicles

* Wireless Monitoring and automobile services

* Includes regarding banks, credit card and financial companies

* Mobile Online Banking and electronic commerce. * Communications between devices Proximity (NFC or Near Field Communications). * Mobile terminal as a means of entrance fees, vending machine products , Public transportation. * Payments based custom circumstances such as location.

* Includes vending machines * Includes access security systems and scanning.

Health

* Includes databases dental centers, hospitals and institutes of Insurance * Includes control devices * Includes websites with advice and access to information to results of

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* Automatic updating of automotive applications. * Databases real-time information based on location and access to traffic updates. * Pay the toll with the mobile device. * Internet access from the car to allow interactivity for online gaming and access to audio and video downloads.

* Mobile access to health advice sites. * Access to personal data base of clinical history, radiographs, etc. * Remote diagnostics with video support. * Access to online medical advice

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medical examinations.

at both national and international.

* Access to TV news and events in real time Journalism

Security and control

Consumer Applications

* Includes newspapers, magazines, radio and television stations, blogs, etc..

* Access to blogs to exchange of views * Access to the servers that store information not recent news.

* Monitoring high-definition * Includes alarms for cars and mobile and access to reports of buildings. alarms installed in buildings * Includes monitoring and * Storage and online monitoring reporting of security systems of surveillance cameras * Includes access systems * Control of heating equipment * Includes control of heating and air conditioning and air conditioning. * Includes integrated security * With LTE terminals will have applications in many services greater storage capacity for content monitor. * Integration of devices on a Gateway (Home Gateway at home), including printers, digital appliances, audio equipment, televisions, surveillance systems, game consoles. * Interconnection of Home Gateway with small nodes called Femtocells which allow better network coverage indoors. * Reading E-books or electronic books

* Remote access to devices connected to the Home Gateway. Access from the mobile terminal to backup cameras. * Access to applications hosted on the web (Cloud services). * Download and access to books in electronic format.

* Access to servers and download Software (Software as a Service).

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In relation to these services, Ovum, which specializes in researching trends in telecommunications, made a report of the LTE industry. As part of that, there were more than 30 interviews with operators, suppliers, regulators and standards bodies, as well as end-user research, for which they were interviewed about 550 people, divided between the U.S., Korea , Japan, Germany, France, Italy, UK and Spain. The results of the survey was conducted among regular users of 3G data services, indicate that LTE will stimulate further growth in demand video services and other multimedia services (35% - 40%), but will be access e-mail, web browsing and search, online shopping and social networking services will be increased consumption registering a growth of use between 15% and 25%. Location-based services (linked to GPS) and telecommunication services for the automobile, are seen as important areas of application that end users see as attractive. For his part, although it is possible to support some of these services mentioned in legacy networks, namely 2G and 3G, will be the capacity, scalability and performance characteristics of network access and transport as well as a broader ecosystem services and applications, which will differentiate from its predecessors LTE.

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8.4.5

The LTE Ecosystem

LTE will be characterized by a complex ecosystem that includes operators, service providers, devices, components, applications and content and platform developers. For this reason, LTE along with the transformation of the business model of operators, provide the company with the business environment that will enable operators to reductions in capital and operating costs in an increasingly competitive market. The ecosystem also includes regulators and standardization. LTE standards are being implemented by the chip vendors to the point that the first chips and devices are already being used in interoperability testing and performance. These trials and testing initiatives supported by the industry through NGMN and LSTI, the latter playing a key role in the extent of testing and experimentation activities. As part of this ecosystem, collaborative efforts in the industry involve the coordination of their players to allow all the benefits of LTE will be thrown into the world market efficiently. The following figure illustrates the major stakeholders in the ecosystem and the relationships between them.

Figure 117 - LTE ecosystem

The following figure supports the existence of interactions among many industry players, hence the so-called "Ecosystem LTE."The ecosystem in question is divided into three components: the Foundation Group, The Enabler Group and the Momentum Group.

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• The Foundation Group consists of the vendor community, which includes chip vendors, device vendors, infrastructure providers, test equipment manufacturers, software developers and application providers and services. Members of this group work together to provide three products related to LTE: LTE infrastructure equipment, user devices, which includes mobile phones, laptops, application specific devices, game consoles and consumer electronics, all of which provide access and interfaces with the third group, which includes the content, services and applications • The Enabler Group is formed by standardization bodies, regulators and industry players. Through them, the group develops and provides technology standards, establishes the regulatory framework, and ensures the alignment of industry players for the optimal development of LTE. • The Momentum Group consists of telecommunications operators worldwide. Your support has encouraged the development of LTE, which has encouraged equipment vendors to deliver the first commercial products to meet work plans that have provided operators for the year 2010. Linked to this, once the LTE technology was introduced, the growth of the ecosystem depend on operators to commit to deploy their networks. This will encourage all other ecosystem members invest and devote more resources to this development. In summary, the report noted OVUM in this paper indicates that the rapid and effective progress is being made across the industry to attain, in the LTE ecosystem, a commitment of all parties, thus allowing a better evolution of technology, devices and applications to market.

Figure 118 - LTE Ecosystem value chain

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8.4.6

For TeliaSonera

With the first commercial deployment of LTE network by TeliaSonera, there are a number of elements that the other operators should take into account in order to learn from the experiences of the mobile operator. Ericsson and TeliaSonera announced Huawei and its network providers to implement their LTE networks. These deployments were conducted at the 2.6 GHz band, which has been one of the recommended bands in the world for the deployment of 4G. For the January 13, 2010, TeliaSonera announced that it will continue expanding its LTE network in the Baltic countries and in 25 other municipalities in Sweden and four municipalities in Norway. The core of the network 4G/LTE, in other words, the EPC will be issued only to the Swedish company Ericsson, while the radio network, will be delivered by Ericsson and Nokia Siemens Network. This agreement will expand LTE networks in Sweden, Norway and Finland between 2010 and 2011. It is noteworthy that in May this year was awarded to TeliaSonera (Denmark) 2x20MHz bandwidth of 10MHz spectrum pair and odd spectrum (TDD) at the haunting of 2.5GHz. Because of this, the president of businesses in the area of mobile services TeliaSonera, Håkan Dahlström Danish announcement to customers that have LTE technology at your fingertips in less than a year. In summary below highlights some important aspects in relation to the operator Teliasonera: • Clients: According to surveys conducted by the operator TeliaSonera, the new LTE network users habits have changed considerably in the use of mobile. The same download large files, watch more videos on line, and television and web browsing also increased significantly. Of the users surveyed, more than half of the users sure would not change back to 3G. • Devices: Initially, the device offered a dongle Samsung LTE only for broadband access to data. It is hoped that the standardization of voice in LTE and the launch in the market of smartphones that support LTE can offer a whole range of data services, voice, SMS and a variety of applications. • Pricing: TeliaSonera has decided to offer flat-rate data with 30GB of monthly usage. Operators and industry experts are reserved to comment on this decision but are expectant on earnings that may generate in the future or when other competitors enter the market. • Spectrum: The Scandinavian LTE network is operating in the 2.6 GHz band, opting for a frequency that gives them great ability but not much coverage. In other parts of Europe have been auctioned off frequencies for the digital dividend, so that future deployments are expected to take place in these bands.

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• Performance: Although theoretically LTE provides peak downlink rates higher than 100Mbps, a recent study showed that barely reached half of this performance. The average download rates were approximately 16 Mbps, which is a breakthrough in relation to 3G but does not yet reach promised to LTE. Be analyzed when the network reaches a greater maturity in order to establish the true performance of LTE in real operating environments.

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8.5

Conclusions

• LTE will provide data services with high bandwidth and quality of service, taking this a great impact on business strategies in terms of providing data services. • In turn, the use of LTE provides resource management and some networking solutions provide the solutions are, which is expected to automatically configure and optimize the network with this minimizing operating costs. • LTE will serve to unify the broadband and mobile telephony, offering the possibility that the end user can access new converged multimedia services, some of which could only be provided from fixed access networks. • Today you are considering initiatives to implement services such as voice and SMS messaging on LTE technology by implementing solutions such as Circuit Switched Fallback (CSFB), One Voice based on IMS and Volga. • Leading manufacturers related to the telecommunications industry are closely involved with the development and deployment of LTE networks. Currently in the market, and LTE equipment available for the core (Core) and access network, some operators such as TeliaSonera case, are already implementing the first LTE networks in some cities. • It has been stated that the choice of the frequency used for the deployment of LTE, is an aspect that should be considered in the strategy of each operator concerned. As has been observed, theoretically the lower frequency bands are of considerable interest because of its wide coverage capability, a factor that benefits of mobile broadband services, however the high capacity offered by these frequencies, the acquisition of this spectrum may be more expensive. • It was possible to observe internationally recognized operators are betting on LTE implement three main frequencies: 700 MHz, 2100 MHz and 2600 MHz In turn, the possibility exists that operators currently using 850 MHz bands like, make a reuse and realignment in these bands. Despite this the choice of the band in which each operator decides to implement LTE, depend on aspects such as frequency of operation that equipment manufacturers are betting, and this path is being marked as the deployments that are making these operators at the forefront in the implementation of technology. • If the operator deploys LTE in the 850 and 2100 MHz bands, it could do by refarming in the first band and designing short-range LTE islands in the band of 2100 MHz in areas of high demand for data traffic, getting the maximum capacity this technology as carriers would have 2x20 MHz. However, it is known that the 850 MHz band currently used by the operator in Costa Rica to offer third-generation it using WCDMA technology, which requires 5 MHz for its operation. Therefore, if you want to use the 850 MHz band would necessarily have to isolate the cells in 5 MHz of 20 MHz

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• As for using the 700 MHz band, in Costa Rica is expected in the medium term the conversion from analogue to digital (DVB-T or DTT), which will free up a significant portion of radio spectrum in this band it would have high demand due to high capacities offered. Despite this, Latin America, the process is delayed, because it is not yet defined the standard for digital TV in most countries, so the possibility of having the band in this region was postponed at least until 2015. • It has been shown that technically there is the possibility of both LTE network interface with legacy networks, namely 2G and 3G and a 3G network to evolve towards LTE. This will ensure that technologies such as HSPA+ and LTE to coexist, being complementary to LTE/HSPA+, offering improvements in capacity. • LTE terminals operate on different frequencies and technology access to the network is different (OFDMA, SC-FDMA) for GSM and UMTS so the end user will have to change or terminal. For the client will not be affected by a high cost of terminal, operators should offer the terminals within comfortable service plans to suit different clients and different services for a fixed period as is currently the 3G handsets, in this case looking for additional services leveraging the high bandwidth you can provide. • The third-generation networks, specifically developed for the Release 6 and 7 can be migrated to LTE (Release 8) through software updates, replacement or addition of cards and replacing the appropriate frequency antennas and MIMO type.

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9

Acronyms

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1G 2G 3G 3GPP 3GPP2 4G AAA ADSL2+ ARPU ARQ AS ASN AUC AVP B3G BBERF BBU BGCF BS BSC BSS BTS CAPEX CCPU CDMA CDMA 2000 1X CDMA 2000 1X EV-DO CDMA 2000 1X EV-DO REV A CDMA2000 CN CPGA CSCF CSFB CSN DCS DHCP DL DOCSIS EDGE

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First Generation Second Generation Third Generation Third Generation Partnership Project Third Generation Partnership Project 2 Fourth Generation Authentication Authorization and Accounting Asymmetrical Digital Subscriber Line 2+ Average Revenue Per User Automatic Repeat Request Application Server Access Service Network Authentication Center Attribute Value Pairs Beyond 3G Barrier Binding and Event Report Finction Base Band Unid Breakout Gateway Control Function Base Satation Base Station Controller Base Station Subsystem Base Transceiver Station CAPital EXpenditures Cash Cost Per User Code Division Multiple Access Code Division Multiple Access 1x Code Division Multiple Access 1x Evolution-Data Only Code Division Multiple Access 1x Evolution-Data Only Rev A Code Division Multiple Access 2000 Core Network Cash Per Gross Addition Call Session Control Function Circuit Switched Fall Back Conectivity Service Network Digital Cellular Service Dynamic Host Configuración Protocol Downlink Data Over Cable Service Interface Specification Enhanced Data for GSM Evolution

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EEUU E-GSM EIR EMM EPC EPDG EPS ESM E-UTRA E-UTRAN EVDO FDD FFT FTTH FTTN FTTX GERAN GGSN GMSC GPRS GPS GRAN GSM GTP GUTI HARQ HFC HLR HSDPA HSPA HSPA+ HSS HSUPA ICE ICIC I-CSCF iDEN IEEE IETF IMEI IM-MGW

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United States Extended GSM-900 Band (includes Standard GSM-900 band) Equipment Identity Register EPS Mobility Management Evolved Packet Core Evolved Packet Data Gateway Evolved Packet System EPS Session Management Evolved UMTS Terrestrial Radio Access Evolved UMTS Terrestrial Radio Access Network Evolution Data Optimizad Frequency Division Duplexing Fast Fourier Transform Fiber to The Home Fiber to The Node Fiber to the X GSM EDGE Radio Access Network Gateway GPRS Support Node Gateway MSC General packet radio service Global Positional System Generic Radio Access Network Global System for Mobile Communications GPRS Tunneling Protocol Global Unique Temporary Identity Hybrid Automatic Repeat and Request Hibrid Fiber Coax Home Location Register High Speed Download Packet Access High Speed Packet Access High Speed Packet Access + Home Subscriber Server High Speed Upload Packet Access Instituto Costarricense de Electricidad Inter Cell Interferente Coordination Interrogating CSCF Integrated Digital Enhanced Network Institute of Electrical and Electronics Engineers Internet Engineering Task Force International Mobile Equipment Identities Intermediate Media Gateway

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IMS IMSI IMT IMT-2000 IP IPv4 IPv6 ISI ITU kbps LTE MAC MAN Mbps MGCF MGW MHz MIMO MME MMS MRFC MRFP MS MSC MTU NGA NGMN NGN OFDM OFDMA OPEX P- GSM PAPR PCC PCEF PCRF PCS P-CSCF PDC PDCP PDN PHY

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IP Multimedia Subsystem International Mobile Subscriber Identity International Mobile Telecommunications International Mobile Telecommunications-2000 Internet Protocol Internet Protocol version 4 Internet Protocol version 6 Inter Simbol Interferente International Telecommunication Union kilobits per second Long Term Evolution Medium Access Control Metropolitan Area Network Megabits per second Media Gateway Control Function Media GateWay Megahertz Multiple Input Multiple Output Mobile Management Entity Multimedia Messaging System Multimedia Resource Function Controller Multimedia Resource Function Processor Mobile Station Mobile Switching Center Maximum Transmission Unit New Generation Access New Generation Mobile Networks New Generation Network Orthogonal Frequency Division Multiplexing Orthogonal Frequency Division Multiple Access Operational EXpenditures Standard or Primary GSM Peak to Average Power Ratio Policy and Charging Convergente Policy and Charging Enforcement Function Policy and Charging Resource Function Personal Communications Service Proxy CSCF Celular Digital Personal Packet Data Convergence Protocol Packet Data Networks Physical

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PLMN PMIP PSTN QoS RA RADIUS, RAN RAT R-GSM RLC RNC RNS RRC RRU S GW, SAE SCFDMA S-CSCF SGSN SIP SLF SMS SON SR-VCC SS SUTEL TAU TCP/IP TDD TDM TDMA TD-SCDMA T-GSM TSG TTI UE UIT UIT -R UL UMB UMTS

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Public Land Mobile Network Proxy Mobile IP Public Switched Telephone Network Quality of Service Routing Area Remote Authentication DIAL In User Service Radio Access Network Radio Access Technology Railways GSM-900 Band (includes Standard and Extended GSM-900 band) Radio Link Control Radio Network Controller Radio Network Subsystem Radio Resource Control Remote Radio Unit Serving Gateway System Architecture Evolution Single Carrier Frequency Division Multiple Access Serving CSCF Serving GPRS Support Node Session Initiation Protocol Subscription Locator Function Short Message System Self Optimizing Networks Single Radio Voice Call Continuity Subscriber Station SUPERINTENDENCIA DE TELECOMUNICACIONES Tracking Area Updating Transmission Control Protocol Time Division Duplexing Time Division Multiplexing Time Division Multiple Access Time Division Synchronous Code Division Multiple Access TETRA-GSM Technical Specifications Group Transmisión Time Interna User Equipmet Unión Internacional de Telecomunicaciones Union Internacional de Telecomunicaciones Radicomunicaciones Uplink Ultra Mobile Broadband Universal Mobile Telecommunications System

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USB UTRA UTRAN VLR VoIP WAP W-CDMA WG Wi-Fi WiMAX WiMAX II WLAN IW

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Universal Serial Bus UMTS Terrestrial Radio Access UMTS Terrestrial Radio Access Network Visitor Location Register Voice over IP Wireless Application Protocol Wideband CDMA Working Groups Wide Fidelity Worldwide Interoperability for Microwave Access Worldwide Interoperability for Microwave Access Release 2 Wireless Local Area Network Inter Working

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