501 Introduction to LTE

Course 501

LTE: Long Term Evolution Fourth Generation Wireless

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 1

Course Outline 

What is LTE?



Overview of Competing 4 th Generation Systems and Spectrum Structure of the LTE RF signals, uplink and downlink LTE Network Architecture • All-IP operation • “Flat” Architecture

 

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 2

Course Outline 

What is LTE?



Overview of Competing 4 th Generation Systems and Spectrum Structure of the LTE RF signals, uplink and downlink LTE Network Architecture • All-IP operation • “Flat” Architecture

 

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 2

What is LTE? 





Fourth generation wireless technologies offer much higher data speeds, much lower latency, more sophisticated Quality-of-Service, lower cost per bit, and simpler/less expensive/more robust network architectures. LTE, Long Term Evolution, is a fourth-generation wireless technology • Already supported by most US wireless operators as their choice for our genera on ep oymen an an m gra on Two other technologies are also being discussed as potential fourthgeneration wireless technologies •  –   – based on IEEE standard standard 802.16, several versions  – implemented by Sprint in initial markets in 4Q2008 •  –   – proposed by Qualcomm, Qualcomm, based on enhancements enhancements of the 1xEVDO standard, EVDO rev. B and EVDO rev. C.  – Qualcomm withdrew withdrew its ro osal in earl March 2010 due to lack of operator interest in implementing it

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 3

Goals of LTE 





 

Reduce operating expenses (OPEX) and capital expenditures CAPEX Vastly increase data speeds/spectral density compared to 3G technologies: >150 Mb/s downlink, >50 Mb/s uplink, in 20 MHz. , other latency-dependent services Flatten the network architecture so only two node types (base stations and atewa s are involved, sim lif in mana ement and dimensioning Provide a high degree of automatic configuration for the network O timize interworkin between CDMA and LTE-SAE so CDMA operators can benefit from huge economies of scale and global chipset volumes

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 4

Course 501

Spectrum and the Develo ment of Wireless

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 5

Frequencies Used by Wireless Systems

AM

0.3

0.4

0.5

0.6

LORAN

0.7 0.8 0.9 1.0

1.2

Marine

1.4 1.6 1.8 2.0

2.4

3.0

z

3,000,000 i.e., 3x106 Hz

Short Wave -- International Broadcast -- Amateur

CB

30,000,000 i.e., 3x107 Hz VHF LOW Band

30

40

VHF TV 2-6

50

60

70

FM

80 90 100

VHF VHF TV 7-13

120 140 160 180 200

700 + Cellular UHF UHF TV 14-59

0.3

0.4

0.5

3

4

5

Broadcasting March, 2010

0/6

6

300 MHz

GPS

0.7 0.8 0.9 1.0

7

240

300,000,000 i.e., 3x108 Hz DCS, PCS, AWS

8

9

10

1.2

1.4 1.6 1.8 2.0

12

14 16 18 20 22 24 26 28 30 GHz

,

,

,

,

2.4 ,

,

3.0 GHz

.e., x

. .,

Land-Mobile Aeronautical Mobile Telephony Terrestrial Microwave Satellite Course 501 LTE (c)2010 Scott Baxter

Page 6

z

10

Current Wireless Spectrum in the US

700 MHz.

700 MHz

   K    K    N    I    L    L    P    N    U    D    L    L    L    L    E    E    C    N    N C    E    E    I I

800

900

Proposed AWS-2

AWS

1700

PCS

1800

1900

PCS DownLink

   T    A

2000

AWS Down-

2100

, 

 



Modern wireless began in the 800 MHz. range, when the US FCC reallocated UHF TV channels 70-83 for wireless use and AT&T’s Analog technology “AMPS” was chosen. . Radio (ESMR) systems and converted to Motorola’s “IDEN” technology The FCC allocated 1900 MHz. spectrum for Personal Communications Services, “PCS”, auctioning the frequencies for over $20 billion dollars , former TV channels 52-69 for wireless use, “700 MHz.” The FCC also auctioned spectrum near 1700 and 2100 MHz. for Advanced Wireless Services, “AWS”.

North American Cellular Spectrum Uplink Frequencies (“Reverse Path”) 824

835

Downlink Frequencies (“Forward Path”) 845

849

requency,

z

870

A

Paging, ESMR, etc. 825

846.5

Ownership and Licensing



890

880

B

869

891.5

Frequencies used by “A” Cellular Operator Initial ownership by Non-Wireline companies  Frequencies used by “B” Cellular Operator Initial ownership by Wireline companies 

In each MSA and RSA, eligibility for ownership was restricted • “A” licenses awarded to non-telephone-company applicants only • “B” licenses awarded to existing telephone companies only • subsequent sales are unrestricted after system in actual operation

March, 2010

Course 501 LTE (c)2010 Scott Baxter

894

Page 8

Development of North America PCS 

By 1994, US cellular systems were seriously overloaded and looking for capacity relief • The FCC allocated 120 MHz. of spectrum around 1900 MHz. for new wireless telephony known as PCS (Personal Communications Systems), and 20 MHz. for unlicensed services • allocation was divided into 6 blocks; 10-year censes were auct one to g est ers PCS Licensing and Auction Details • A & B spectrum blocks licensed in 51 MTAs (Major Trading Areas ) • Revenue from auction: $7.2 billion (1995) • C, D, E, F blocks were licensed in 493 BTAs (Basic Trading Areas) • C-block auction revenue: $10.2 B, D-E-F block auction: $2+ B (1996) • Auction winners are free to choose any desired technology

493 BTAs



PCS SPECTRUM ALLOCATIONS IN NORTH AMERICA A

D

B

E F

C

15

5

15

5

15

1850 MHz.

March, 2010

5

unlic. unlic. data voice

  1910 MHz.

A

D

B

E F

C

15

5

15

5

15

5 

1930 MHz.

Course 501 LTE (c)2010 Scott Baxter

  1990 MHz.

Page 9

Potential Spectrum for LTE 



LTE Potential Spectrum different target market segments; one of the key differentiator is that WiMAX is primarily TDD (Time-Division-Duplex) and will address operators that have unpaired spectrum whereas LTE is FDD (Frequency. Time Division Duplexing allows the up-link and down-link to share the same spectrum where as Frequency Division Duplexing allows that the up-link and down-link to transmit on different frequencies. 3GGP LTE , industry believes the first deployments of LTE network are likely to take place at the end of 2009, beginning of 2010. In the section, we will look at the most probable FDD spectrum bands su a e or e u ure ep oymen o u ear ng n m n e a ove mentioned schedule and the current level of activity related to spectrum regulation and allocation, it is likely that the information contained in this paper will require regular revision to remain accurate.

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 10

The US 700 MHz. Spectrum and Its Blocks

  

o sa s y grow ng eman or w re ess a a serv ces as we as traditional voice, the FCC has also taken the spectrum formerly used as TV channels 52-69 and allocated them for wireless The TV broadcasters will completely vacate these frequencies when , At that time, the winning wireless bidders may begin building and operating their networks In many cases, 700 MHz. spectrum will be used as an extension of existing operators networks. In other cases, entirely new service will be provided.

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 11

The 700 MHz. Band in the US  

700 MHz In the U.S. this commercial spectrum was auctioned in April 2008. The auction included 62 MHz of spectrum broken into 4 blocks; Lower A (12 , , , , Upper D (10 MHz). These bands are highly prized chunks of spectrum and a tremendous resource: the low frequency is efficient and will allow for a network that doesn’t require a dense buildout and provides better inbuilding penetration than higher frequency bands. February 17, 2009 as the date that all U.S. TV stations must vacate the 700 MHz spectrum, making it fully available for new services. • The upper C block came along with “open access” rules. In the FCC’s context “o en access” means that there would be “no lockin and no blocking” by the network operator. That is, the licensee must allow any device to be connected to the network so long as the devices are compatible with, and do not harm the network (i.e., no “locking”), and cannot impose restrictions against content, applications, or services that may be accessed over the network (i.e., no “blocking”). The upper oc not meet t e 1.3 on reserve pr ce. s spectrum w likely be reauctioned in the future with a new set of requirements that could give rise to a licensee capable of addressing first responders’ interoperability and broadband requirements.



the world, possibly allowing global roaming on compatible bands.

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 12

Advanced Wireless Services Spectrum  

 



Advanced Wireless Services (AWS) In Se tember 2006 the FCC com leted an auction of AWS licenses (“Auction No. 66”) in which the winning bidders won a total of 1,087 licenses. In the spirit of the U.S. government’s free-market policies, the FCC does not usually mandate that specific technologies be used in specific bands. Therefore, owners of AWS spectrum are free to use it for , , . This spectrum uses 1.710-1.755 GHz for the uplink and 2.110-2.155 GHz for the downlink. 90 MHz of spectrum divided this into six frequency blocks A through F. Blocks A, B, and F are 20 megahertz each and blocks C, D, and E, are 10 megahertz each. The FCC wanted to harmonized its “new” AWS spectrum as closely as possible with Europe’s UMTS 2100 band. However, the lower half of urope s an a mos comp e e y over aps w e . band, so complete harmonization wasn’t an option. Given the constraint the FCC harmonized AWS as much as possible with the rest of the world. The upper AWS band lines up with Europe’s UMTS 2100 base transmit , ’ transmit band.

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 13

Advanced Wireless Services: The AWS Spectrum







To further satisfy growing demand for wireless data services as well as ra ona vo ce, e as a so a oca e more spec rum or wireless in the 1700 and 2100 MHz. ranges The US AWS spectrum lines up with International wireless , “ ” practical than in the past Many AWS licensees will simply use their AWS spectrum to add introduce their service to new areas

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 14

AWS Spectrum Blocks



The AWS spectrum is divided into “blocks”



blocks in specific areas This is the same arrangement used in original 800 MHz. cellular, 1900 MHz. PCS and the new 700 MHz. allocations

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 15

AWS Spectrum Winners 



March, 2010

The maps at left show the territorial winnin s of various wireless operators in the AWS auctions AWS licenses in the various AWS spectrum blocks cover different sized territories; the maps show the combined territory controlled by each winner at the conclusion of

Course 501 LTE (c)2010 Scott Baxter

Page 16

Global Wireless Frequency Allocations Available for 4G Technologies

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 17

Current Wireless Technologies and New Directions for 4G

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 18

Multiple Access Methods FDMA

FDMA: AMPS & NAMPS •Each user occupies a private Frequency,

Power

separation from other users on the same frequency

TDMA

,

•Each user occupies a specific frequency but only during an assigned time slot. The

Power

other time slots.

CDMA CDMA

• ac user uses a s gna on a part cu ar frequency at the same time as many other users, but it can be separated out when

Power

of its own March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 19

Multiple Access Methods OFDM, OFDMA

OFDM   r   e   w   o    P

Frequency

MIMO

•Orthogonal Frequency Division Multiplexing; Ortho onal Fre uenc Division Muli le Access •The signal consists of many (from dozens to thousands) of thin carriers carrying symbols •In OFDMA the s mbols are for multi le users •OFDM provides dense spectral efficiency and robust resistance to fading, with great flexibility of use

MIMO •Multiple Input Multiple Output • , exploitation of multiple antennas at the base station and the mobile to effectively multiply the throu h ut for the base station and users

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 20

Differences Between OFDM and OFDMA



In OFDM, users are assigned fractions of the total subcarriers available for fractions of the available time , basis aimed at maximizing throughput • It is simpler to allow users to share the signal

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 21

A Technical Comparison , ,

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 22

LTE 

 

LTE (Long Term Evolution) is a 3GPP project to improve UMTS to meet future requirements a ms o mprove e c ency, re uce cos s, mprove serv ces, a capability to use newly allocated spectrum, and integrate better with other open Standards LTE itself is not a standard, but part of upcoming UMTS release 8 LTE specific technical goals and details are: • 100 Mbit/s downloads, 50 Mbit/s uploads for each 20 MHz. of spectrum used • • Latency under 5 ms for small IP packets • Increased spectrum flexibility, using slices from 1.25 to 20 MHz. depending on availability of spectrum (great for “fitting in” around an ’ • Optimal cell size of 5 km, 30 km sizes with reasonable performance, and up to 100 km cell sizes supported with acceptable performance • Co-existence with legacy standards (users calls or data sessions can transparently transfer to LTE where available • LTE is an AIPN, All-IP Network

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 23

WiMax Compared with LTE

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 24

LTE Key Air Interface Features 



Downlink: OFDM / OFDMA • bandwidth • #subcarriers scales with bandwidth (76 ... 1201) • fre uenc selective schedulin in DL i.e. OFDMA • Adaptive modulation and coding (up to 64-QAM) Uplink: SC-FDMA (Single Carrier - Frequency Division Multiple Access) • A FFT-based transmission scheme like OFDM, but with better PAPR (Peak-to-Average Power Ratio) • The total bandwidth is divided into a small number of frequency . ., bandwidth) • Uses Guard Interval (Cyclic Prefix) for easy Frequency Domain Equalisation (FDE) at receiver

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 25

Deployment Timeframe of LTE and WiMax

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 26

UMB Radio Access Network EV-DO Rev. A One Carrier EV-DO Rev. B Two Carriers . Three Carriers EV-DO Rev. C UMB 20 MHz





Re uired Spectrum

Peak Forward Link Throughput

Peak Reverse Link Throughput

1.25 MHz

3.1 Mb/s

1.8 Mb/s

2.5 MHz

6.2 Mb/s

3.6 Mb/s

3.75 MHz

9.3 Mb/s

5.4 Mb/s

20 MHz

275 Mb/s

75 Mb/s

. , . carriers in parallel for higher speeds. UMB (Ultra Mobile Broadband, 1xEV-DO rev. C) attempts to compete with LTE and Wimax by using a transmission format very similar to LTE. , November 2008 abandoned its UMB proposal and all development UMB Summary • Uses OFDMA, FDD, scalable bandwidth 1.25-20 MHz • Data speeds >275 Mbit/s downlink and >75 Mbit/s uplink • FL advanced antenna techniques, MIMO, SDMA and Beamforming • Low-overhead signaling and RL CDMA control channels • Inter-technology and L1/L2 handoffs, independent Fwd/Rev Handoffs • Dead! 

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 27

LTE: Long-Term Evolution

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 28

The LTE Air Interface:

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 29

The LTE Downlink Signal  





The LTE signal (also known as E-UTRA) uses OFDMA modulation for the downlink and Single Carrier FDMA (SC-FDMA) for the uplink An OFDM si nal consists of dozens to thousands of ver thin carriers spaced through available spectrum • each carries a part of the signal • the number of carriers can be adjusted to fit in the available spectrum OFDM has a Link spectral efficiency greater than CDMA • Using QPSK, 1QAM, and 64QAM modulation along with MIMO, EUTRA is much more efficient than WCDMA with HSDPA and HSUPA. LTE Downlink Si nal S ecifics • OFDM subcarrier spacing is 15 kHz and the maximum number of carriers is 2048 • 2048 carriers fill 30.7 MHz., 72 subcarriers fill 1.08 MHz. • o es mus e capa e o rece v ng su carr ers u can transmit as few as 72 carriers when available spectrum is restricted • Time slots are 0.5 ms, subframes 1.0 ms, a radio frame is 10 ms long • MIMO is a lied both for sin le users and for multi-users to boost cell throughput

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 30

Type 1 Frames: For Frequency Division Duplex (FDD)





The forward link is transmitted continuously because it has its own frequency This frequency division duplex mode is the most commonly used mode for large LTE systems

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 31

Type 2 - TDD





The forward link is transmitted discontinuously, alternating with the reverse link on the same fre uenc This arrangement allows effective LTE operation in a small amount of spectrum, but does limit the capacity of the system

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 32

Downlink OFDM Modulation

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 33

Elements and Blocks

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 34

Physical Resource Block Parameters





A resource block is normally 12 OFDM carriers, spaced 15 kHz. a art so the block occu ies 180 KHz. The number of resource blocks varies depending on the amount of spectrum available for the LTE signal to occupy. It ranges from 6 blocks for a 1.4 MHz. wide signal, to 100 blocks for 20 MHz.

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 35

Generic Frame Sequences



Each OFDM s mbol be ins with a c clic refix of duration below:

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 36

Downlink Resource Elements





One download slot normally consists of seven OFDM symbol periods on each of the individual subcarriers of the OFDM signal ne sym o on one su carr er s called a “Resource Element” For transmission to a user, the certain number of subcarriers to carry the user data. Those subcarriers for the period of one downlink slot are called a Resource Block.

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 37

Downlink Physical Resources and Mapping

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 38

Example of Downlink Control Signal Mapping 

March, 2010

This figure shows a typical exam le of ma in the various downlink control signals to the slots and resource elements which hold

Course 501 LTE (c)2010 Scott Baxter

Page 39

LTE Physical Channels

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 40

LTE Physical Signals

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 41

An LTE Inter-eNB Handover



Notice that there is a trigger based on UE measurements



typically 60 ms. The handover is arranged essentially between the two eNBs, with the AGW implementing a path switch as the final step, and releasing the



Handover in LTE is hard, since the eNBs are on different frequencies in a frequency plan much like GSM or IDEN

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 42

SISO, MISO, SIMO, MIMO 







Single-Input Single-Output is the default mode for radio links over the ears and the baseline for further comparisons. Multiple-Input Single Output provides transmit diversity (recall CDMA2000 . power required, but does not increase data rate. It’s also a delicious  Japanese soup. Single-Input Multiple Output is “receive diversity”. It reduces the necessary SNR but does not increase data rate. It’s rumored to be named in honor of  Dr. Ernest Simo, noted CDMA expert. Multiple-Input Multiple Output is highly effective, using the differences in path dimension to hold additional signals and increase the total data speed.

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 43

SU-MIMO, MU-MIMO, Co-MIMO 





March, 2010

Single-User MIMO allows the sin le user to ain throughput by having multiple essentially independent paths for data Multi-User MIMO allows multiple users on the reverse link to transmit , increasing system capacity Cooperative MIMO allows a user to receive its si nal from multiple eNBs in combination, increasing reliability and throughput

Course 501 LTE (c)2010 Scott Baxter

Page 44

The LTE Air Interface:

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 45

The LTE Uplink Signal 

LTE Uplink Signal Specifics , (64QAM optional) modulation. • SC-FDMA has a low Peak-to-Average Power Ratio (PAPR) . • If virtual MIMO / Spatial division multiple access (SDMA) is introduced the data rate in the uplink direction can be station (1 to 4) • With this technology more than one mobile can reuse the same resources

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 46

Differences between OFDMA and SC-FDMA As Used on the LTE Downlink and Uplink

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 47

UL SC-FDMA Subcarrier Options



On the reverse link, there are two ways to assign subcarrier frequencies to



One is Localized Subcarriers, which gives one user a single block of adjacent carriers • as critical The other is Distributed Subcarriers • this provides superior protection against selective fading • this requires very precise frequency control to avoid interference



March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 48

Uplink Physical Resources and Mapping

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 49

Uplink Format PUCCH 0 or 1

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 50

LTE Network Architecture:

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 51

System Architecture Evolution Objectives  

New core network architecture to support high-throughput / low latency LTE access system • Simplified network architecture • All-IP network • All services via PS domain only, No CS domain • Support mobility between multiple heterogeneous access systems  – 2G/3G, LTE, non 3GPP access systems (e.g. WLAN, WiMAX) • Inter-3GPP handover (GPRS E-UTRAN): Using GTP-C handover • Inter 3GPP non-3GPP mobility: Evaluation of host based (MIPv4, MIPv6, DSMIPv6) and network based (NetLMM, v4, v6 protoco s

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 52

SAE Architecture: Baseline

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 53

SAE Architecture Interfaces (1) S1-U S1 Interface User Plane S1-U reference point (LTE SAE) Reference point between EUTRAN and SGW for the per-bearer user plane tunneling and inter-eNB path switching during handover. The trans ort rotocol over this interface is GPRS Tunnelin Protocol-User lane (GTP-U) S2a interface (LTE SAE) It provides the user plane with related control and mobility support between trusted non-3GPP IP access and the Gateway. S2a is based on Proxy Mobile IP. To enable access via trusted non-3GPP IP accesses a o no suppor , a a so suppor s en o e v FA mode S2b interface (LTE SAE) Provides the user plane with related control and mobility support between evolved Packet Data Gateway (ePDG) and the PDN GW. It is based on Proxy Mobile IP.

S2c interface (LTE SAE) Provides the user plane with related control and mobility support between UE and the PDN GW. This reference point is implemented over trusted and/or untrusted non-3GPP Access and/or 3GPP access. This S3 interface (LTE SAE) The interface between SGSN and MME and it enables user and bearer information exchange for inter 3GPP access network mobility in idle and/or active state. It is based on Gn reference point as defined between SGSNs S4 interface (LTE SAE) Provides the user plane with related control and mobility support between SGSN and the SGW and is based on Gn reference point as defined between SGSN and GGSN.

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 54

SAE Architecture Interfaces (2) S5 interface (LTE SAE) Provides user plane tunneling and tunnel management between SGW and PDN GW. It is used for SGW relocation due to UE mobility and if the SGW needs to connect to a non-collocated PDN GW for the required . depending on the protocol used, namely, GTP and the IETF based Proxy Mobile IP solution S5a interface (LTE SAE) Provides the user plane with related control and mobility support between MME/UPE and 3GPP anchor. It is FFS whether a standardized S5a exists or whether MME/UPE and 3GPP anchor are combined into one entity. S5b interface (LTE SAE) Provides the user plane with related control and mobility support between 3GPP anchor and SAE anchor. It is FFS whether a standardized S5b exists or whether 3GPP anchor and SAE anchor are combined into one entity. S6 interface (LTE SAE) Enables transfer of subscription and authentication data for authenticating/authorizing user access to the evolved system (AAA interface). authenticating/authorizing user access to the evolved system (AAA interface) between MME and HSS S7 interface (LTE SAE) Provides transfer of (QoS) policy and charging rules from Policy and Charging Rules Function (PCRF) to Policy and Charging Enforcement Function (PCEF) Rules Function (PCRF) to Policy and Charging Enforcement Function (PCEF) in the PDN GW. This interface is based on the Gx interface

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 55

LTE SAE Network Element Functions 



The LTE SAE network is greatly sim lified com ared to the GPRS-EDGE-HSPA networks with their SGSNs and GGSNs In the LTE SAE, there are only two main elements: • aGW gateways, which perform header compression, c p er ng, an earer control functions. • eNB evolved node Bs, which protocols and radio resource control

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 56

UMTS HSPA vs LTE-SAE Network Architectures 

March, 2010

This figure compares the network architecture of an LTE SAE with the architecture of the earlier UMTS HSPA networks

Course 501 LTE (c)2010 Scott Baxter

Page 57

Integration of LTE, EVDO and HSPA

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 58

LTE/SAE Network Functional Elements: eRAN Evolved Radio Access Network (RAN)  Consists of a single node, eNodeB (eNB) interfacing with the UE • • • • •

PHYsical (PHY) Medium Access

• • • • • • •

includes user-plane header-compression and encryption. Radio Resource Control (RRC) functionality (control plane) a o resource managemen , a m ss on con ro , sc e u ng enforcement of negotiated UL QoS cell information broadcast c p er ng ec p er ng o user an con ro p ane a a compression/decompression of DL/UL user plane packet headers

Radio Link Control (RLC) Packet Data Control Protocol (PDCP)

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 59

LTE/SAE Network Functional Elements: SGW Serving Gateway (SGW) • routes and forwards user data packets • acts as mobility anchor for the user plane plane during inter• acts as anchor for mobility between LTE and other 3GPP technologies  – erm na es n er ace, re ays ra c e ween systems and PDN GW) • For idle state UEs, SGW terminates the DL data path  – tr ggers pag ng w en ata arr ves or t e . • Manages/stores UE contexts (parameters of IP bearer service, network internal routing information) • Performs replication of the traffic in case of lawful interception. March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 60

LTE/SAE Network Functional Elements: MME Mobility Management Entity (MME)  The key control-node for the LTE access-network. • retransmissions • Bearer activation/deactivation • Chooses SGW for UE at initial attach and intra-LTE HO to new CN • Authenticates user (by interacting with the HSS) • Non-Access Stratum (NAS) signaling terminates at the MME • Generates/allocates temporary identities for UEs. • • • • •

Enforces UE roaming restrictions Is termination point for ciphering/integrity protection for NAS signaling Handles securit ke mana ement. Performs Lawful interception of signaling Provides control plane function for mobility between LTE and 2G/3G access networks, terminating the S3 interface from the SGSN. • Terminates S6a interface towards the home HSS for roaming UEs. March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 61

LTE/SAE Network Functional Elements: PDN GW Packet Data Network Gateway (PDN GW) • Provides UE connectivity to external packet data networks as point of exit and entry of traffic for the UE • PDN GW for accessing multiple PDNs • Performs policy enforcement • ac e er ng or eac user • Charging support • Lawful Interception and packet screening • Acts as mobility anchor between 3GPP and non-3GPP technologies such as WiMAX, 3GPP2 (CDMA 1X and EvDO).

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 62

LTE SAE Network Key Features (1) EPS to EPC





performs control-plane functionality (MME) from the network entity that performs bearer-plane functionality (SGW) with a well-defined open interface between them (S11). Since E-UTRAN will provide higher bandwidths to enable new services as well as to improve existing ones, separation of MME from SGW implies that SGW can be based on a platform optimized or g an w pac e process ng, w ere as e s ase on a platform optimized for signaling transactions. This enables selection of more cost-effective platforms for, as well , . providers can also choose optimized topological locations of SGWs within the network independent of the locations of MMEs in order to optimize bandwidth reduce latencies and avoid concentrated points of failure.

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 63

LTE SAE Network Key Features (2)  

S1-flex Mechanism load sharing of traffic across network elements in the CN, the MME and the SGW, by creating pools of MMEs and SGWs and allowing each eNB to be connected to multiple MMEs and SGWs in a pool.

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 64

LTE Progress Milestones 

2006 at ITU trade fair in Hong Kong, by Siemens: • video supervision • Mobile IP-based handover between the LTE radio







system Researchers at Nokia Siemens Networks/Heinrich Hertz Institute February 2007 at 3G World Congress - Nortel publicly demonstrated the first complete LTE air interface implementation includin OFDM-MIMO SC-FDMA and multi-user MIMO u link Verizon Wireless plans to begin LTE trials in 2008.

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 65

LTE Network Manufacturers 

The “Big 4”: • Ericsson AB (Nasdaq: ERIC) • • Alcatel-Lucent (NYSE: ALU) • Huawei Technologies Co. Ltd. • Fujitsu – for NTT DoCoMo, remote RF pods • Kyocera •  – , 2G/3G cabinets • NEC – very dense, cabinets or pole-mount form factors • Nortel – standalone and rackmount within CDMA & GSM BTS • ZTE – “Unified Hardware Platform” NEC March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 66

LTE Handset Manufacturers 

Samsung for MetroPCS , fallback • Announced Mar. 25, • Will be deployed in Las Vegas mkt.

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 67

Ericsson LTE eNodeB and Test UE



Ericsson 2007 LTE testbed hardware • eNB in rack using large components; to be further miniaturized

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 68

eNB Developments 

Xilinx's LTE Baseband Targeted Design Platform • Intended for incorporation in manufacturer’s LTE eNBs • http://www.youtube.com/watch?v=0n3Fbbca21Y&feature=channel

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 69

LTE RF Design Tools 









Atoll from Forsk • http://www.forsk.com/  Aircomm ENTERPRISE: ADVANTAGE, ASSET, NetACT • http://www.aircominternational.com/  Mentum Planet • http://www.mentum.com/index.php?page=mentumplanet&hl=en_US Ascom TEMS Cell lanner • http://www.ascom.com/en/index/products-solutions/yourindustry/industry/5/solution/ant-planning-anddesign/product/tems-cellplanner-2/solutionloader.htm EDX SignalPro 7.2 • http://www.edx.com/products/signalpro.html



• www.symena.com March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 70

LTE Network Planning Considerations 



The Basic Requirements: Coverage and Capacity • Required capacity from traffic projections & business plan  – With cell configurations, drives total number of cells required • Required coverage from marketing objectives  – With link budget, drives total number of cells required Design Factors: • Link budget (power, sensitivity) of selected eNB/UE equipment • ’ penetration) • Cell Antenna Configuration: SISO, MISO, SIMO, MIMO -  – calculate per Resource Block  – thermal noise over 180 kHz (168 ksps) = -121.4 dbm  – LTE is a 1:1 re-use system; overlap must exist for mobility

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 71

LTE Field Optimization Tools 





Agilent E6474A LTE Drive-Test . . . . • See available measurements and KPIs on following page ASCOM TEMS • http://www.ascom.com/en/lte-technology-temsproducts.pdf COPS from Celcite – Network-side Optimization Tool  • htt ://www.celcite.com/ roducts.html

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 72

LTE UE Field Measurements and KPIs 

RF Key Performance Indicators • Reference Signal Received Power • Received Signal Strength Indicator • Reference Signal Receive Quality. Defined as N × , the number of resource blocks across which RSSI was measured

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 73

LTE: Impressive Network Automation 





Network Configuration –  • eNB disco discovery very and and auto-configu auto-configuration ration in in network network • Automatic Neighbor Relationships (ANR) • eNB Cell Cell-Level -Level Carrie Carrierr Bandwidth Bandwidth Assignment Assignment Network Operations • Co ni niti tiv ve ra radi dio o re reso sour urc ce ma man na em emen entt • self-healing, auto-inventory mgt., automated upgrade mgt . Network Optimization , • handover parameter optimization, interference control mgt. • radio parameter optimization from macro to picocells

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 74

WiMAX Specifics

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 75

WiMax 

 

WiMAX (Worldwide Interoperability for Microwave Access) is based on the IEEE 802.16 standard • Provides MAN (Metropolitan Area Network) broadband connectivity • also known as the IEEE WirelessMAN air interface. WiMAX-based systems can have ranges up to 30 miles. The 802.16d standard of extending 802.16 supports three physical layers (PHYs). • e man a ory mo e s -po n r ogona Frequency Division Multiplexing (OFDM). • The other two PHY modes are Single Carrier (SC) and • For interest, the corresponding European standard—the ETSI HiperMAN standard—defines a single PHY mode identical to the 256 OFDM modes in the 802.16d standard.

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 76

WiMax Technical Details 





 

WiMAX can be used over many different frequency ranges • . . • 802.16a covers 2GHz-to-11GHz • WiMAX range can reach 30 miles with a typical cell radius of 4–6 miles. WiMAX's channel sizes range from 1.5 to 20MHz, offer corresponding data rates • Rates from 1.5Mbps to 70Mbps on a single channel • one carrier can support thousands of users WiMAX supports ATM, IPv4, IPv6, Ethernet, and VLAN services • facilitates many service possibilities in voice and data WiMAX could be used as a backhaul technology to connect 802.11 wireless LANs and commercial hotspots with the Internet WiMax systems would be deployed much like cellular systems.

March, 2010

Course 501 LTE (c)2010 Scott Baxter

Page 77