3G Overview

Part I 3G Overview

1 Company Confidential

What’s New in WCDMA? Characteristic to WCDMA • RAKE receiver takes advantage of multipath propagation • Fast power control keeps system stable by using minimum power necessary for links • Soft handover ensures smooth handovers

Multiservice Environment • Data speed – In RAN1 bit rate varies from 8 kbps up to 384 kbps – Variable bit rate also available – Bit rate gradually grows up to 2 Mbps • Service delivery type – Real-time (RT) & non real-time (NRT) • Quality classes for user to choose – Different error rates and delays • Traffic asymmetric in uplink & downlink • Common channel data traffic (FACH) • Inter-system handovers

Air Interface • Capacity and coverage coupled “cell breathing” • Neighbor cells coupled via interference • Soft handover • Fast power control • Interference limited system (e.g. GSM frequency limited) 2

Company Confidential

UMTS network architecture Gi

PSTN

GMSC

GGSN

AuC C PSTN

HLR

PSTN

VLR

B

Gf Gs

B

MSC

Gn Gr

EIR F

G

Gc

H

D

VLR

SGSN

MSC

E

Gp

CN A

Gb

IuPS

IuCS

RNS

BSS BSC Abis

BTS

Iur

RNC

RNC

Iubis

BTS

Node B

Node B

cell

Um

Uu ME

Microsoft Word Document

Ref. 3GPP TS23.002

SIM-ME i/f

SIM

or

Cu

USIM MS

Company Confidential

3

3G Spectrum Allocation

4 Company Confidential

IMT2000 Frequency Allocation for UMTS 1900

1920

TDD UL/DL

1980

FDD UL

2010

2025

2110

MSS TDD UL UL/DL

2170

FDD DL

2200

MSS DL

MHz

FDL FDL/UL FUL

FDD Mode

TDD Mode Company Confidential

5

3G Terms •

IMT 2000 – Third generation mobile systems as defined by ITU – Global recommendation

•

3GPP – 3rd Generation Partnership Project (Forum for a WCDMA standardization) – Involved: ETSI (Europe), ARIB (Japan), TTA (Korea), T1P1 (USA), TTC (Japan) and CWTS (China)

•

UMTS – Third generation telecommunication system, that is subject to specifications produced by 3GPP

•

WCDMA – Air Interface technology adapted for UMTS Terrestrial Radio Access (UTRA)

•

UTRA-FDD – WCDMA in 3GPP, FDD mode

•

UTRA-TDD – WCDMA in 3GPP, TDD mode

•

CDMA2000 – Air Interface technology proposal from TR45.5 (USA) on evolution of IS-95 (CDMA) 6 Company Confidential

UMTS System Characteristics • • • • • • • • • • • • • • •

W-CDMA : 5 MHz Carrier Spacing : multiples of 200 kHz W-CDMA spreading rate = 3.84 Mchip/s Chip Rate = 3.84 MHz Raised cosine filtering with roll-off 0.22 Information bit rate: between 8 kbit/s and 2 Mbit/s (currently up to 384 Kbit/s) Spreading Factor (SF): 4 -256 Multiple Access Scheme : Wideband DS-CDMA Duplex Scheme : FDD and TDD modes Carrier Spacing : 4.4 – 5.4 MHz 10 ms frame with 15 time slots NodeB synchronization: asynchronous Highly variable data rates, data rate constant within 10 ms frame Bandwidth on demand, efficient resource usage Multiple services with different variable data rates over one physical channel

7 Company Confidential

Key features of WCDMA •Soft handoff: user equipment (UE) and base stations use special rake receivers that

allow each UE to simultaneously communicate with multiple base stations. The diversity gain associated with soft handoff is known as the "soft handoff gain factor".

•Multipath reception: the rake receivers also allow the UE to decode multiple signals

that have traveled over different physical paths from the base station. For example, one signal may travel directly from the base station to the UE, and another may reflect off a large building and then travel to the UE. This phenomenon, "multipath propagation", also provides a diversity gain. The same effect occurs on the uplink from the UE to the base station.

•Power control: transmissions by the UE must be carefully controlled so that all transmissions are received with roughly the same power at the base station. If power control is not used, a “near-far” problem, where mobiles close to the base station overpower signals from mobiles farther away, occurs. The base station uses a fast power control system to direct the mobile to power up or power down as its received signal level varies due to changes in the propagation environment. Likewise, on the downlink, transmissions from the base stations are power-controlled to minimize the overall interference throughout the system and to ensure a good received signal by the UE.

8 Company Confidential

Key features of WCDMA Frequency reuse of 1: every base station in the CDMA system operates on the same frequency for a given carrier, so no frequency planning is required. As every site causes interference to every other site, careful attention must be paid to each site's radio propagation. Soft capacity: capacity and coverage are intertwined in CDMA, depending on the number of users in the system and the amount of interference allowed before access is blocked for new users. By setting the allowed interference threshold lower, coverage will improve at the expense of capacity. By setting the threshold higher, capacity will increase at the expense of coverage. Because of the fundamental link between coverage and capacity, cells with light traffic loads inherently share some of their latent capacity with more highly loaded surrounding cells.

9 Company Confidential

WCDMA Compared to GSM and CDMA IS-95 WCDMA vs. GSM WCDMA has some similarities with GSM technology, however, it is a fundamentally different technique for allowing multiple users to share the same spectrum and as a result it has many differences.

10 Company Confidential

WCDMA Compared to GSM and IS-95 CDMA

11 Company Confidential

Part II WCDMA Fundamentals

12 Company Confidential

WCDMA = DS-CDMA •WCDMA is a code-division multiple access technology which separates each user’s voice or data information by multiplying the information by pseudo-random bits called "chips". •The pseudo-random bit sequences have a rate of 3.84 Mcps (millions of chips per second), resulting in the narrowband information bits of the user being spread across a much wider bandwidth of approximately 5 MHz. • For this reason, CDMA technology is sometimes referred to as “spread spectrum.” •The user data (signal) is first spread by the channelisation code (based on Hadamard matrix) called Orthogonal Variable Spreading Factor (OVSF) Code. •OVSF code has the property that two different codes from the family are perfectly orthogonal if in phase

13 Company Confidential

TDMA based System

14 Company Confidential

W-CDMA based System

15 Company Confidential

Processing Gain and Spreading

16 Company Confidential

Spreading and Despreading

The spreading sequences must have good correlation properties to facilitate the separation of the wanted signal from all others: •One sharp and dominant peak of the autocorrelation function for zero phase shift •As small as possible values of the autocorrelation function for all out-of-phase shift •As small as possible values of the cross-correlation function for all phase shift 17 Company Confidential

Spreading and Despreading

18 Company Confidential

CDMA Multiple Access Advantages : Multiple Access Features 1. All Users’ Signals overlap in TIME and FREQUENCY 2. Correlating the Received Signal despreads ONLY the WANTED SIGNAL p

p

S1

RECEIVER of USER 1

S1xC1 f

f

p

p

p

p

S2

S1 = S1 X C1 X C1

S2 X C2 X C1

f

f

S2xC2 f

f 19 Company Confidential

CDMA Multiple Access Advantages : Interference Rejection p

p

S1

S1xC1 f

f p

p

p

I

I

S1 IxC1 f f

f

Correlation Narrowband Interference Spread the power Only a small portion of the interfering signal energy passes the filter and remain as residual interference Company Confidential

20

CDMA Principles m1(t)

Tc : Chip Rate of the PN Code Tb : Information rate (voice/data)

M1(f) 1

-1

Tb

1

2Tb

3Tb

1/Tb

f

C1(f)

c1(t)

f Tc m1(t).c1(t)

4Tc

1/Tb

1/Tc

C1(f)* M1(f) f 1/Tb Company Confidential

1/Tc

21

Processing gain (Gp) •Gp = Wc/Wi •Where –Wc: chip rate –Wi: user data rate

f

Wc

Wi •The more processing gain the system has, the more the power of uncorrelated interfering signals is suppressed in the despreading process •Thus, processing gain can be seen as an improvement factor in the SIR (Signal to Interference Ratio) of the signal after despreading •Example: Voice AMR 12.2 Kbps Æ Gp = 10*log(3840000/12200)= 25 dB •After despreading the signal power has to be typically few dB above the interference and noise: Eb/No = 5dB; therefore the required wideband signal-to-interference ratio is 5dB – Gp = -20 dB. •In other words, the signal power can be 20 dB under the interference and the WCDMA receiver can still detect the signal •Wideband signal-to-interference ratio is also called carrier-to-interference ratio: C/I •Thanks to spreading and desporeading, C/I can be much lower in WCDMA than GSM (C/I = 9-12 dB) 22 Company Confidential

Spreading in WCDMA Consists of 2 operations: 1. Channelization • Transforms each symbol (data bit) to the number of chips (increases bandwidth) • Number of chips per symbol = Spreading Factor (SF) 2. Scrambling • Scrambling code is applied Scrambling Code Data

TX Bit Rate

Chip Rate

Chip Rate

Channelization code (OVSF)

23 Company Confidential

OVSF properties •In the spreading process, information symbols, which occupy a relatively narrow bandwidth, are multiplied by a high-rate spreading code consisting of chips •The resulting spread signal has a wider bandwidth dependent on the number of chips per symbol •In the de-spreading process, the spreading code is multiplied by the spread signal to recover the original data symbols. The de-spreading process converts the wide bandwidth spread signal back to the original narrower bandwidth of the data symbols •Spreading codes (OVSF) are specially designed to allow the symbols from multiple users to occupy the same spectrum at the same time, while still allowing the original information to be retrieved. •Codes are allocated in RNC •Restrictions: another physical channel may use a certain code in the tree if no other physical channel to be transmitted using the same code tree is using a code that is on an underlying branch, i.e. using a higher SF generated from the intended spreading code to be used. Neither can a smaller SF code on the path to the root of the tree be used

SF4 Company Confidential

24

Scrambling code properties • The OVSF codes are effective only when the channels are perfectly synchronized at symbol level • The loss in cross-correlation, e.g. due to multipaths, is compensated by the additional scrambling operation • Scrambling codes are used to separate different cells in the downlink and different terminals in the uplink • They have good correlation properties (interference averaging) and are always used on top of the spreading codes, thus not affecting the transmission bandwidth

25 Company Confidential

Usage of the codes Usage

Length

Channelization Code

Scrambling Code

Uplink: separation of physical data (DPDCH) and control channels (DPCCH) for the same terminal Downlink: separation of downlink connections to different users within on cell

Uplink: Separation of terminals

4-256 chips In downlink also 512 chips

Uplink: 10ms = 38400 chips

Downlink: Separation of sectors (cells)

Downlink: 10ms = 38400 chips

Number of codes

Spreading Factor indicates the number of codes under one scrambling code

Uplink: over 16 millions Downlink: 512

Code Family

Orthogonal Variable Spreading Factor (OVSF)

10ms code: Gold Code 66.7µs code: Extended code family

Spreading

Yes, indicates bandwidth

No, does not affect bandwidth

26 Company Confidential

Receivers • •

Both NodeB and Terminals use the same type of correlation receivers Due to multipath propagation it’s necessary to use multiple correlation receivers (fingers) in order to recover (combine) the energy from all paths coherently and obtain multipath diversity

27 Company Confidential

Wide Band Channel • Definition: • A channel is defined wide when its bandwidth (Bw) is greater than the Coherence Bandwidth: Bw >> ∆fc

1 ∆fc = 2πSτ

28 Company Confidential

Wide Band Channel – Delay Spread Channel impulse response (power delay profile) and delay spread

Dominant Path

τ1

29 Company Confidential

Wide Band Channel – Narrow/Wide Band System Microsoft Word Document

30 Company Confidential

WCDMA and GSM in TU3 Channel

31 Company Confidential

Optimal Receiver for WCDMA signal • For a channel with only one signal path optimal receiver is one correlator (code de-spreading and integration Basic unit of Rake Receiver

32 Company Confidential

Optimal Receiver for WCDMA signal • In a multipath environment optimal receiver utilizes several correlators (Rake Fingers) tuned for dominant delays = Rake receiver

Adobe Acrobat Document

33 Company Confidential

Rake Receiver • Rake finger delays tuned based on channel impulse response estimation • Code Matched Filter, Search Finger • Fingers combined with Maximal Ratio combining • Performance of Rake Receiver depends on the channel powers delay profile • Max path delay difference vs. chip time Æ amount of multipath diversity

34 Company Confidential

Rake Receiver - Combining • Combined signal without and with phase estimation and correction (example 6 path channel)

35 Company Confidential

Maximal Ratio Combining of Symbols Transmitted signal

Received signal (+noise) Finger n.1

Time and phase adjustment

Combined signal (+ residual noise)

Finger n.2

Finger n.3

UE WBT S

36 Company Confidential

Maximal Ratio Combining of Symbols Received symbol+noise

Transmitted symbol

Modified with channel estimate and relative delay compensation (for combining)

Combined symbol + residual noise

Finger n.1

Finger n.2

Finger n.3

UE WBTS

37 Company Confidential

WCDMA in TU Channel

time

• High level of multipath diversity 38 Company Confidential

WCDMA in Indoor Channel

Rake Finger RESOLUTION = 0.26µs Chip period = 1/3840000 s = 0.26µs

• No multipath diversity. •0.26µs delay can be obtain if the difference in path lengths is at least 78 m (speed of light / chip rate). IS-95 (≈1Mcps) Æ 300m path lengths difference Company Confidential

39

Part III Scrambling Code Planning

40 Company Confidential

Scrambling Code Planning

41 Company Confidential

Scrambling Code Planning

42 Company Confidential

Scrambling Code Planning

43 Company Confidential

Scrambling Code Planning

44 Company Confidential

Scrambling Code Planning

45 Company Confidential

Scrambling Code Planning

46 Company Confidential

Scrambling Code Planning

47 Company Confidential

Scrambling Code Planning

48 Company Confidential

Scrambling Code Planning

49 Company Confidential

Scrambling Code Planning

50 Company Confidential

Scrambling Code Planning

51 Company Confidential

Part IV Physical Layer

52 Company Confidential

Channel Mapping In GSM, we distinguish between logical and physical channels. In UMTS there are three different types of channels: • Logical Channels Logical Channels were created to transmit a specific content. There are for instance logical channel to transmit the cell system information, paging information, or user data. Logical channels are offered as data transfer service by the Medium Access Control (MAC) layer to the next higher layer. Consequently, logical channels are in use between the mobile phone and the RNC.

• Transport Channels (TrCH) The MAC layer is using the transport service of the lower, the Physical layer. The MAC layer is responsible to organise the logical channel data on transport channels. This process is called mapping. In this context, the MAC layer is also responsible to determine the used transport format. The transport of logical channel data takes place between the UE and the RNC.

• Physical Channels (PhyCH) The physical layer offers the transport of data to the higher layer. The characteristics of the physical transport have to be described. When we transmit information between the RNC and the UE, the physical medium is changing. Between the RNC and the Node B, where we talk about the interface Iub, the transport of information is physically organised in so-called Frames. Between the Node B and the UE, where we find the WCDMA radio interface Uu, the physical transmission is described by physical channels. A physical channel is defined by the UARFCN and the a spreading code in the FDD mode. 53

Company Confidential

Radio Interface Channel Organisation

Logical Channels content is organised in separate channels, e.g. System information, paging, user data, link management

Transport Channels logical channel information is organised on transport channel resources before being physically transmitted

Physical Channels (UARFCN, spreading code)

Frames Iub interface 54

Company Confidential

Logical Channels

There are two types of logical channels (FDD mode): Control Channels (CCH): • Broadcast Control Channel (BCCH)

System information is made available on this channel. The system information informs the UE about the serving PLMN, the serving cell, neighbourhood lists, measurement parameters, etc. This information permanently broadcasted in the downlink.

• Paging Control Channel (PCCH) Given the BCCH information the UE can determine, at what times it may be paged. Paging is required, when the RNC has no dedicated connection to the UE. PCCH is a downlink channel.

• Common Control Channel (CCCH) Control information is transmitted on this channel. It is in use, when no RRC connection exists between the UE and the network. It is a bi-directional channel, i.e. it exists both uplink and downlink.

• Dedicated Control Channel (DCCH) Dedicated resources were allocated to a UE. These resources require radio link management, and the control information is transmitted both uplink and downlink on DCCHs.

Traffic Channels (TCH): • Dedicated Traffic Channel (DTCH) User data has to be transferred between the UE and the network. Therefore dedicated resources can be allocated to the UE for the uplink and downlink user data transmission.

• Common Traffic Channel (CTCH) Dedicated user data can be transmitted point-to-multipoint to a group of UEs. Company Confidential

55

Transport Channels (TrCH) Logical Channels are mapped onto Transport Channels. There are two types of Transport Channels (FDD mode): Common Transport Channels: • Broadcast Channel (BCH) It carries the BCCH information. • Paging Channel (PCH) It is in use to page a UE in the cell, thus it carries the PCCH information. It is also used to notify UEs about cell system information changes. • Forward Access Channel (FACH) The FACH is a downlink channel. Control information, but also small amounts of user data can be transmitted on this channel. • Downlink Shared Channel (DSCH) This channel is used downlink. Dedicated user data and control information for several mobile phones can be transmitted with one DSCH. • Random Access Channel (RACH) This uplink channel is used by the UE, when it wants to transmit small amounts of data, and when the UE has no RRC connection. It is often used to allocated dedicated signalling resources to the UE to establish a connection or to perform higher layer signalling. It is a contention based channel, i.e. several UE may 56 attempt to access UTRAN simultaneously. Company Confidential

Transport Channels (TrCH) • Common Packet Channel (CPCH) Similar to the RACH, it is a contention based uplink channel. In contrast to the RACH, it can be used to transmit larger amounts of (bursty) traffic. Dedicated Transport Channels: • Dedicated Channel (DCH) Dedicated resources can be allocated both uplink and downlink to a UE. Dedicated resources are exclusively in use for the subscriber. On the following figures. you can see the mapping of logical channels onto transport channels, as well as the mapping of transport channels onto physical channels.

57 Company Confidential

Physical Channels (PhyCH) Physical Channels are characterised by •UARFCN, •scrambling code, •channelisation code (optional), •start and stop time, and •relative phase (in the uplink only, with relative phase being 0 or π/2) Transport channels can be mapped to physical channels. But there exist physical channels, which are generated at the Node B only, as can be seen on the next figures.

58 Company Confidential

Channel Mapping DL (Network Point of View) Logical Channels

Transport Channels

Physical Channels P-SCH S-SCH CPICH

BCCH

BCH

P-CCPCH

PCCH

PCH

S-CCPCH PICH

CCCH FACH

CSICH

CTCH

CD/CA-ICH

DCCH DTCH

AICH

DSCH

PDSCH

DCH

DPDCH DPCCH

Company Confidential

59

Channel Mapping UL (Network Point of View) Logical Channels

Transport Channels

Physical Channels

CCCH

RACH

PRACH

DCCH

CPCH

PCPCH

DTCH

DCH

DPDCH I branch DPCCH Q branch 60

Company Confidential

Transport Formats TFCS TB TB

TB TTI

TTI

TTI

TB TB TB TB

TB

DCH 2

TB

TB TB

TBS

DCH 1 TFS

TTI

TTI

TTI

TFC TB TBS

TF Transport Block Transport Block Set

TFS TFC TFCS

TF Transport Format Transport Format Set Transport Format Combination Transport Format Combination61 Set

Company Confidential

Cell Synchronisation When a UE is switched on, it starts to monitor the radio interface to find a suitable cell to camp on. But it has to determine, whether there is a WCDMA cell nearby. If a WCDMA cell is available, the UE has to be synchronised to the downlink transmission of the system information – transmitted on the physical channel P-CCPCH – before it can make a decision, in how far the available cell is suitable to camp on. Initial cell selection is not the only reason, why a UE wants to perform cell synchronisation. This process is also required for cell re-selection and the handover procedure. Cell synchronisation is achieved with the Synchronisation Channel (SCH). This channel divides up into two sub-channels: •Primary Synchronisation Channel (P-SCH) (SLOT and CHIP SYNCHRONIZATION) A time slot lasts 2560 chips. The P-SCH only uses the first 10% of a time slot. A Primary Synchronisation Code (PSC) is transmitted the first 256 chips of a time slot. This is the case in every UMTS cell. If the UE detects the PSC, it has performed TS and chip synchronisation. •This is typically done with a single matched filter matched to the primary synchronization code which is common for all cells. The slot timing of the cell can be obtained by decoding peaks in the matched filter output 62 Company Confidential (continued on the next text slide)

Synchronisation Channel (SCH) 2560 Chips 256 Chips

Primary Synchronisation Channel (P-SCH) CPP C

CP

CP

CP

Secondary Synchronisation Channel (S-SCH) Cs1

Cs2

Slot 0

Cs15

Slot 1

Slot 14

Cs1

Slot 0

10 ms Frame Cp = Primary Synchronisation Code Cs = Secondary Synchronisation Code Company Confidential

63

Cell Synchronisation • Secondary Synchronisation Channel (S-SCH) • (FRAME SYNCH and Scrambling Code Group DETECTION) The S-SCH also uses only the first 10% of a timeslot; Secondary Synchronisation Codes (SSC) are transmitted. There are 16 different SSCs, which are organised in a 10 ms frame (15 timeslots) in such a way, that • the beginning of a 10 ms frame can be determined, and • 64 different SSC combinations within a 10 ms frame are identified. There is a total of 512 primary scrambling codes, which are grouped in 64 scrambling code families, each family holding 8 scrambling code members. The 15 SSCs in one 10 ms frame identify the scrambling code family of the cell‘s downlink scrambling code. • The sequence permits downlink frame synchronization and indicate which of the code grouping the downlink scrambling code belongs to. • This is done by correlating the received signal with all possible secondary synchronization code sequences and identifying the maximum correlation value. Since the cyclic shifts of the sequences are unique, the code group as well as the frame synchronization is determined

64 Company Confidential

SSC Allocation for S-SCH scrambling code group

slot number 0

1

2

3

group 00 group 01

1

1

2

8

1

1

5 16

7

3 14

group 02 group 03

1

2

1 15

5

5 12

1

2

3

1

8

6

group 04

1

2 16

6

6 11 15

group 05

1

3

7

4

group 62

1 9 11 12 15 12 9 13 13 11 14 10 16 15 14 16 5 1 1 9 12 10 15 13 14 9 14 15 11 11 13 12 16 10 5 1

group 63

4

4

5

6

15 9 10 15

1

5

5

7

8

9

8 10 16 16

10 11 12 13 14 2

7 15

7 16

3 10

5 12 14 12

10

16

6 11

2 16 11 15

12

2

5

4

3

7

5 12

1 15 12 16 11

2

5

6

8

3

8

2

4

8

6

7

6

I monitor the S-SCH

11

15

5 65 Company Confidential

Common Pilot Channel (CPICH) With the help of the SCH, the UE was capable to perform chip, TS, and frame synchronisation. Even the cell‘s scrambling code group is known to the UE. But in the initial cell selection process, it does not yet know the cell‘s primary scrambling code. There is one primary scrambling code in use over the entire cell, and in neighbouring cells, different scrambling codes are in use. There exists a total of 512 primary scrambling codes. The CPICH is used to transmit in every TS a pre-defined bit sequence with a fixed data rate of 30 kbps, which corresponds to spreading factor 15. The CPICH divides up into a mandatory Primary Common Pilot Channel (P-CPICH) and optional Secondary CPICHs (S-CPICH). The P-CPICH is in use over the entire cell. And it is the first physical channel, where a spreading code is in use. A spreading code is the product of the cell‘s scrambling code and the channelisation code. The channelisation code is fixed: Cch,256,0. I.e., the UE knows the P-CPICH‘s channelisation code, and it uses the P-CPICH to determine the cell‘s primary scrambling code by trial and error (UE tries 8 SC Codes of the group identified). The P-CPICH is not only used to determine the primary scrambling code. It also acts as - phase reference for most of the physical channels, - measurement reference in the FDD mode (and partially in the TDD mode). There may be zero or several S-CPICHs. Either the cell‘s primary scrambling code or its secondary scrambling codes can be used. In contrast to the P-CPICH, it can be broadcasted just over a part of the cell. 66 Company Confidential

Primary Common Pilot Channel (P-CPICH) 10 ms Frame 2560 Chips 256 Chips

Synchronisation Channel (SCH)

CP P-CPICH

applied speading code = cell‘s primary scrambling code ⊗ Cch,256,0

Cell scrambling code? I get it with trial & error!

• Phase reference • Measurement reference

P-CPICH

67 Company Confidential

CPICH as Measurement Reference The UE has to perform a set of L1 measurements, some of them refer to the CPICH channel: • CPICH RSCP RSCP stands for Received Signal Code Power. The UE measures the RSCP on the Primary-CPICH. The reference point for the measurement is the antenna connector of the UE. The CPICH RSCP is a power measurement of the CPICH. The received code power may be high, but it does not yet indicate the quality of the received signal, which depends on the overall noise level. • UTRA carrier RSSI. RSSI stands for Received Signal Strength Indicator. The UE measures the received wide band power, which includes thermal noise and receiver generated noise. The reference point for the measurements is the antenna connector of the UE. • CPICH Ec/No The CPICH Ec/No is used to determine the „quality“ of the received signal. It gives the received energy per received chip divided by the band‘s power density. The „quality“ is the primary CPICH‘s signal strength in relation to the cell noise. (Please note, that transport channel quality is determined by BLER, BER, etc. ) If the UE supports GSM, then it must be capable to make measurements in the GSM bands, too. The measurements are based on the • GSM carrier RSSI 68 The wideband measurements are conducted on GSM BCCH carriers. Company Confidential

P-CPICH as Measurement Reference CPICH RSCP Received Signal Code Power (in dBm) CPICH Ec/No received energy per chip divided by the power density in the band (in dB) UTRA carrier RSSI

received wide band power, including thermal noise and noise generated in the receiver CPICH Ec/No = CPICH RSCP UTRA carrier RSSI CPICH Ec/No

CPICH RSCP

UTRA carrier RSSI

0: -24 1: -23.5 2: -23 3: -22.5 ... 47: -0.5 48: 0

0: -115 1: -114 2: -113 : 88: -27 89: -26

0: -110 1: -109 2: -108 : 71: -39 72: -38 73: -37

Ec/No values in dB

RSCP values in dBm

RSSI values in dBm

Company Confidential

69

Primary Common Control Physical Channel (P-CCPCH) The UE knows the cell‘s primary scrambling code. It now wants to gain the cell system information (MIB,SIB), which is transmitted on the physical channel PCCPCH. The channelisation code of the P-CCPCH is also known to the UE, because it must be Cch,256,1 in every cell for every operator. By reading the cell system information on the P-CCPCH, the UE learns everything about the configuration of the remaining common physical channels in the cell, such as the physical channels for paging and random access. As can be seen from the P-CCPCH‘s channelisation code, the data rate for cell system information is fixed. The SCH is transmitted on the first 256 chips of a timeslot, thus creating here a peak load. The cell system information is transmitted in the timeslot except for the first 256 chips. By doing so, a high interference and load at the beginning of the timeslot is avoided. This leads to a net data rate of 27 kbps for the cell system information. Channel estimation is done with the CPICH, so that no pilot sequence is required in the P-CCPCH. (The use of the pilot sequence is explained in the context of the DPDCH later on in this document.) There are also no power control (TPC) bits transmitted to the UE‘s.

70 Company Confidential

Primary Common Control Physical Channel (P-CCPCH) 10 ms Frame 2560 Chips 256 Chips

Synchronisation Channel (SCH)

CP P-CCPCH

Finally, I get the cell system information

P-CCPCH

• channelisation code: Cch,256,1 • no TPC, no pilot sequence • 27 kbps (due to off period) • organised in MIBs and SIBs 71 Company Confidential

Primary Common Control Physical Channel (P-CCPCH)

72 Company Confidential

Nokia Parameters for Cell Search • WCEL: PtxPrimaryCPICH The parameter determines the transmission power of the primary CPICH channel. It is used as a reference for all common channels. [-20 dBm … 43 dBm], step 1 dB, default: 33dBm (WPA power = 43 dBm) • WCEL: PtxPrimarySCH Transmission power of the primary synchronization channel, the value is relative to primary CPICH transmission power. [-35 dB … 15 dB], step size 0.1 dB, default: -3 dB • WCEL: PtxSecSCH Transmission power of the secondary synchronization channel, the value is relative to primary CPICH transmission power. [-35 dB… 15 dB], step size 0.1 dB, default: -3 dB

73 Company Confidential

Nokia Parameters for Cell Search • WCEL: PtxPrimaryCCPCH This is the transmission power of the primary CCPCH channel, the value is relative to primary CPICH transmission power. [-35 dB … 15 dB], step size 0.1 dB, default: -5 dB • WCEL: PriScrCode Identifies the downlink scrambling code of the Primary CPICH (Common Pilot Channel) of the Cell. [0 ... 511], default: 0 dB

74 Company Confidential

Secondary Common Control Physical Channel (S-CCPCH) The S-CCPCH can be used to transmit the transport channels • Forward Access Channel (FACH) and • Paging Channel (PCH). More than one S-CCPCH can be deployed. The FACH and PCH information can multiplexed on one S-CCPCH – even on the same 10 ms frame -, or they can be carried on different S-CCPCH. The first S-CCPCH must have a spreading factor of 256, while the spreading factor of the remaining S-CCPCHs can range between 256 (30 Kbps or 15 Ksps) and 4 (1920 Kbps). UTRAN determines, whether a S-CCPCH has the TFCI (Transport Format Combination Indicator) included (supports variable rates). Please note, that the UE must support both SCCPCHs with and without TFCI. S-CCPCH is on air ONLY when there is data to transmit (FACH or Paging) We use SF = 64 Æ 120 Kbps (60 Ksps)

75 Company Confidential

Secondary Common Control Physical Channel (S-CCPCH) 10 ms Frame Slot 0

TFCI (optional)

Slot 1

Slot 2

Data

Slot 14

Pilot bits

• carries PCH and FACH • Multiplexing of PCH and FACH on one S-CCPCH, even one frame possible • with and without TFCI (UTRAN set) • SF = 4..256 • (18 different slot formats) • no inner loop power control Company Confidential

S-CCPCH

76

S-CCPCH and the Paging Process

• The network has detected, that there is data to be transmitted to the UE (MTC). Both in the RRC idle mode and in the RRC connected mode (e.g. in the sub-state CELL_PCH) a UE may get paged. But how does the mobile know, when it was paged? And in order to save battery power, we don‘t want the UE to listen permanently to paging channel – instead, we want to have discontinuous reception (DRX) of paging messages. But when and where does the UE listen to the paging messages? • Cell system information is broadcasted via the P-CCPCH. The cell system information is organised in System Information Blocks (SIB). SIB5 informs the mobile phones about the common channel configuration, including a list of SCCPCH descriptions. The first 1 to K entries transmit the (transport channel) PCH, while the remaining S-CCPCH in the list hold no paging information. • The UE determines the S-CCPCH, where it is paged, by its IMSI and the number of PCH carrying S-CCPCHs K. When paging the UE, the RNC knows the UE‘s IMSI, too, so that it can put the paging message on the correct PCH transport channel. • Discontinuous Reception (DRX) of paging messages is supported. A DRX cycle length k has to be set in the network planning process for the cs domain, ps domain, and UTRAN. k ranges between 3 and 9. If for instance k=6, then the UE is paged every 2k = 640 ms. If the UE is in the idle mode, it takes the smaller k-value of either the cs- or psdomain. If the UE is in the connected mode, it has to select the smallest k-value of 77 UTRAN and the CN, it is not connected to. Company Confidential

S-CCPCH and the Paging Process UTRAN

BCCH (SIB 5) common channel definition, including a lists of

UE

Node B

RNC

Index of S-CCPCHs

0

S-CCPCH carrying one PCH

1

S-CCPCH carrying one PCH

K-1

S-CCPCH carrying one PCH S-CCPCH without PCH

UE‘s paging channel: Index = IMSI mod K e.g. if IMSI mod K = 1

„my paging channel“

S-CCPCH without PCH

Company Confidential

78

The Paging Process Paging Indicator Channel (PICH) UMTS provides the terminals with an efficient sleep mode operation. The UEs do not have to read and process the content, transmitted during their paging occasion on their S-CCPCH. Each S-CCPCH, which is used for paging, has an associated Paging Indicator Channel (PICH). A PICH is a physical channel, which carries paging indicators. A set of (paging indicator) bits within the PICH indicate to a UE, whether there is a paging occasion for it. Only then, the UE listens to the S-CCPCH frame, which is transmitted 7680 chips after the PICH frame in order to see, whether there is indeed a paging message for it. The PICH is used with spreading factor 256. 300 bits are transmitted in a 10 ms frame, and 288 of them are used for paging indication. The UE was informed by the BCCH, how many paging indicators exist on a 10 ms frame. The number of paging indicator Np can be 18, 32, 72, and 144, and is set by the operator as part of the network planning process. The higher Np, the more paging indicators exist, the more paging groups exist, among which UEs can be distributed on. Consequently, the lower the probability, that a UE reacts on a paging indicator, while there is no paging message in the associated S-CCPCH frame. But a high number of paging indicators results in a comparatively high output power for the PICH, because less bits exists within a paging indicator to indicate the paging event. The operator then also has to consider, if he has to increase the number of paging attempts. 79 Company Confidential

S-CCPCH and its associated PICH S-CCPCH frame, associated with PICH frame

τS-CCPCH τPICH PICH frame

= 7680 chips

for paging indication b0 b1

no transmission b286 b287 b288

b299

# of paging Subscribers with Subscribers with indicators per frame Pq indicator Pq indicator (Np) paged => not paged => {b16q, …,b16q+15} = {1,1,…,1} {b16q, …,b16q+15} = {0,0,…,0} 18 (16 bits) {b8q, …, b8q+7} = {1,1,…,1} {b8q, …, b8q+7} = {0,0,…,0} 32 (8 bits) {b4q, …, b4q+3} = {1,1,…,1} {b4q, …, b4q+3} = {0,0,…,0} 72 (4 bits) {b2q, b2q+1} = {1,1} {b2q, b2q+1} = {0,0} 144 (2 bits) Company Confidential

80

Nokia Parameters for S-CCPCH and Paging RAN 1 & RAN1.5 support data rates of 15, 30, and 60 ksym/s for the S-CCPCH. FACH Open Loop power control can be implemented only if the S-CCPCH is dedicated, uplink PC information through the RACH (RAN 2)

• WCEL: NbrOfSCCPCHs The parameter defines how many S-CCPCH are configured for the given cell. Range: [1,2], step: 1; default = 1 (1 = FACH&PCH; 2 = FACH on 1st / PCH on 2nd) •

WCEL: PtxSCCPCH1 (carries FACH & PCH) This is the transmission power of the 1st S-CCPCH channel, the value is relative to primary CPICH transmission power. Range: [-35 dB … 15 dB] , step size 0.1 dB, default: - 5dB

• WCEL: PtxSCCPCH2 (carries PCH only) This is the transmission power of the 2nd S-CCPCH channel, the value is relative to primary CPICH transmission power. Range: [-35 dB … 15 dB] , step size 0.1 dB, default: - 5dB

81 Company Confidential

Nokia Parameters for S-CCPCH and Paging • WCEL: PtxPICH This is the transmission power of the PICH channel. It carries the paging indicators which tell the UE to read the paging message from the associated secondary CCPCH. This parameter is part of SIB 5. [-10 dB..5 dB]; step 1 dB; default: -8 dB (with Np =72) NP Repetition of PICH bits [18, 36, 72, 144] with relative power [-10, -10, -8, -5] dB • RNC: CNDRXLength The DRX cycle length used for CN domain to count paging occasions for discontinuous reception. This parameter is given for CS domain and PS domain separately. This parameter is part of SIB 1. [640, 1280, 2560, 5120] ms; default = 640 ms. • WCEL: UTRAN_DRX_length The DRX cycle length used by UTRAN to count paging occasions for discontinuous reception. [80, 160, 320, 640, 1280, 2560, 5120] ms; default = 320 ms 82 Company Confidential

FACH and S-CCPCH

The transport channel Forward Access Channel (FACH) is used, when relatively small amounts of data have to be transmitted from the network to the UE. In-band signalling is used to indicate, which UE is the recipient of the transmitted data (see MAC PDU with UE-ID type). This common downlink channel is used without (fast) closed loop power control and is available all over the cell. FACH data is transmitted in one or several S-CCPCHs. FACH and PCH data can be multiplexed on one S-CCPCH, but they can also be be transmitted on different S-CCPCHs. The FACH is only transmitted downlink. The FACH is organised in FACH Data Frames via the Iubinterface. Each FACH Data Frames holds the Transmission Blocks for one TFS. The used TFS is identified by the TFI. A TFI is associated with one Transmission Time Interval (TTI), which can be either 10, 20, 40 or 80 ms. The TTI identifies the interleaving time on the radio interface. A FACH Data Frame has header fields, which identify the CFN, TFI, and the Transmit Power Level. The Transmit Power Level gives the preferred transmission power level for the FACH and for the TTI time. The values specified here range between 0 and 25.5 dB, with a step size of 0.1 dB. The value is taken as a negative offset to the maximum power configured for the S-CCPCHs, specified for the FACH. The pilot bits and the TFCI-field may have a relative power offset to the power of the data field, which may vary in time. (The offset is determined by the network.) The power offsets are set by the NBAP message COMMON TRANSPORT CHANNEL SETUP REQUEST, which is sent from the RNC to the Node B. There are two power offset information included: • PO1: defines the power offset for the TFCI bits; it ranges between 0 and 6 dB with a 0.25 step size. • PO3: defines the power offset for the pilot bits; it ranges between 0 and 6 dB with a 0.25 step size. 83 Another important parameter is the maximum allowed power on the FACH: MAX FACH Power. Company Confidential

FACH and S-CCPCH Power offsets for TFCI and TPC defined during channel setup

Transmit Power Level CFNTFI

FACH Data Frame TB

TB

Iub Uu RNC

Node B

max. transmit power for S-CCPCH

UE 0..25.5 dB, step size 0.1 Transmit Power Level

PO3

PO1 TFCI (optional)

Pilot bits

Data 84 Company Confidential

Nokia Parameters for S-CCPCH Power Setting Currently, either one or two S-CCPCHs are supported.

•

WCEL: PowerOffsetSCCPCHTFCI Defines the power offset for the TFCI symbols relative to the downlink transmission power of a Secondary CCPCH. This parameter is part of SIB 5. P01_15/30/60 15 ksps: [0..6 dB]; step 0.25 dB; default: 2 dB 30 ksps : [0..6 dB]; step 0.25 dB; default: 3 dB 60 ksps : [0..6 dB]; step 0.25 dB; default: 4 dB

• WCEL: PowerOffsetSCCPCHPilot Defines the power offset for the pilot symbols relative to the downlink transmission power of a Secondary CCPCH. This parameter is part of SIB 5. P03_15/30/60 15 ksps : [0..6 dB]; step 0.25 dB; default: 2 dB 30 ksps : [0..6 dB]; step 0.25 dB; default: 3 dB 60 ksps : [0..6 dB]; step 0.25 dB; default: 4 dB 85 Company Confidential

Code Tree Capacity

86 Company Confidential

Part V Power Control

87 Company Confidential

Effect of TX & RX Powers on Interference Levels

Downlink transmission power = Interference to the network

Uplink transmission power = Interference to other cells

Uplink received power = Interference to own cell users

Since every TX and RX power is causing interference to others, PC 88 is necessary to limit the interference Company Confidential

CDMA Fundamentals : Power Control Near-Far Problem Pr,1 = EIRP(MS1) - PL1 = 21 - 100 = -79 dBm Pr,2 = EIRP(MS2) - PL2 = 21 - 90 = -69 dBm

PL2 = 90 dB Pr,1 Pr,2 P = 21 dBm

P = 21 dBm

PL1 = 100 dB MS2 MS1 (S/N)1 = Pr,1 - Pr,2 = -10 dB (S/N)2 = Pr,2 - Pr,1 = +10 dB

MS2 must be Power Controlled by -10 dB to have the same S/N for both users MS1 and MS2 Company Confidential

89

Near-Far Effect

90 Company Confidential

Purpose of Power Control in WCDMA

91 Company Confidential

Physical Random Access (Open loop Power Control) Outer Loop Power Control Fast Closed Loop (Inner) Power Control

92 Company Confidential

Physical Random Access (Open loop Power Control) In the random access (based on Slotted ALOHA approach with fast acquisition indication) , initiated by the UE (MOC), two physical channels are involved: • Physical Random Access Channel (PRACH) The physical random access is decomposed into the transmission of preambles in the uplink. Each preamble is transmitted with a higher output power as the preceding one. After the transmission of a preamble, the UE waits for a response by the Node B. This response is sent with the physical channel Acquisition Indication Channel (AICH), telling the UE, that the Node B as acquired the preamble transmission of the random access. Thereafter, the UE sends the message itself, which is the RACH/CCCH of the higher layers. The preambles are used to allow the UE to start the access with a very low output power. If it had started with a too high transmission output power, it would have caused interference to the ongoing transmissions in the serving and neighbouring cells. Please note, that the PRACH is not only used to establish a signalling connection to UTRAN. It can be also used to transmit very small amounts of user data. • Acquisition Indication Channel (AICH) This physical channel indicates to the UE, that it has received the PRACH preamble and is now waiting for the PRACH message part. Company Confidential

93

Random Access – the Working Principle

UE

Node B

No response by the Node B

PRACH (preamble)

No response by the Node B

PRACH (preamble)

I just detected a PRACH preamble

PRACH (preamble)

OLA!

AICH PRACH (message part)

94 Company Confidential

Random Access Timing The properties of the PRACH are broadcasted (SIB5, SIB6). The candidate PRACH is randomly selected (if there are several PRACH advertised in the cell) as well as the access slots (= 2 TIME SLOTS) within the PRACH. 15 access slots are given in a PRACH, each access slot lasting two timeslots or 5120 chips. In other words, the access slots stretch over two 10 ms frames. A PRACH preamble, which is transmitted in an access slot, has a length of 4096 chips. Also the AICH is organised in (AICH) access slots, which stretch over two timeslots. AICH access slots are time aligned with the P-CCPCH. The UE sends one preamble in uplink access slot n. It expects to receive a response from the Node B in the downlink (AICH) access slot n, τp-a chips later on. If there is no response, the UE sends the next preamble τp-p chips after the first one. The maximum numbers of preambles in one preamble access attempt can be set between 1 and 64. The number of PRACH preamble cycles can be set between 1 and 32. If the AICH_Transmission_Timing parameter in the SIB is set to BCCH SIB5 & SIB6 to •0, then, the minimum preamble-to-preamble distance is 3 access slots, the minimum preamble-tomessage distance is 3 access slots, and the preamble-to-acquisition indication is 3 timeslots.

•1, then, the minimum preamble-to-preamble distance is 4 access slots, the minimum preamble-to95 message distance is 4 access slots, and the preamble-to-acquisition indication is 5 timeslots. Company Confidential

Random Access Timing SFN mod 2 = 0

SFN mod 2 = 1

SFN mod 2 = 0

P-CCPCH AICH access slots0

1 2

3 4 5120 chips

UE point of view

5 6

7

9 10 11 12 13 14 0

8

1 2

3 4

5 6

7

(distances depend on AICH_Transmission_Timing )

Acquisition Indication

AICH access slots

4096 chips PRACH access slots Preamble 5120 chips preamble-to-preamble distance τp-p

preamble-to-AI distance τp-a

AS # i

Preamble

Message part

AS # i preamble-to-message distance τp-m

Company Confidential

96

PRACH Power Setting

Preamble_Initial_Power = UL interference + Primary CPICH TX power – CPICH_RSCP + Constant Value

1st preamble: power setting Constant Value attenuation in the DL

estimated receive level

UL interference at Node B -5..10 dB 1..8 dB

Pp-p

Pp-p Preamble

Pp-m Preamble

Preamble # of preambles: 1..64

Message part

# of preamble cycles: 1..32

Company Confidential

97

Nokia Parameters Related to the PRACH and AICH WCEL: PRACHRequiredReceivedCI This UL required received C/I value is used by the UE to calculate the initial output power on PRACH according to the Open loop power control procedure. This parameter is part of SIB 5. [-35 dB..-10 dB]; step 1 dB; default -25 dB. We use - 20 WCEL: PowerRampSteponPRACHPreamble UE increases the preamble transmission power when no acquisition indicator is received by UE in AICH channel. This parameter is part of SIB 5. [1dB..8dB]; step 1 dB; default: 2 dB. We use 1 • WCEL: PowerOffsetLastPreamblePrachMessage The power offset between the last transmitted preamble and the control part of the PRACH message. [-5 dB..10 dB]; step 1 dB; default 2dB • WCEL: PRACH_preamble_retrans The maximum number of preambles allowed in one preamble ramping cycle, which is part of SIB5/6. [1 ... 64]; step 1; default 8. We use 7 98 Company Confidential

Nokia Parameters Related to the PRACH and AICH • WCEL: RACH_tx_Max Maximum number of RACH preamble cycles defines how many times the PRACH pre-amble ramping procedure can be repeated before UE MAC reports a failure on RACH transmission to higher layers. This message is part of SIB5/6. [1 ... 32]; default 8. We use 16 WCEL: PRACHScramblingCode The scrambling code for the preamble part and the message part of a PRACH Channel, which is part of SIB5/6. [0 ... 15]; default 0. • WCEL: AllowedPreambleSignatures The preamble part in a PRACH channel carries one of 16 different orthogonal complex signatures. Nokia Node B restrictions: A maximum of four signatures can be allowed (16 bit field). [0 ... 61440]; default 15. We use 4 • WCEL: AllowedRACHSubChannels A RACH sub-channel defines a sub-set of the total set of access slots (12 bit field). 99 [0 ... 4095]; default 4095. Company Confidential

Nokia Parameters Related to the PRACH and AICH • WCEL: PtxAICH This is the transmission power of one Acquisition Indicator (AI) compared to CPICH power. This parameter is part of SIB 5. [-22 ... 5] dB, step 1 dB; default: -8 dB. • WCEL: AICHTraTime AICH transmission timing defines the delay between the reception of a PRACH access slot including a correctly detected preamble and the transmission of the Acquisition Indicator in the AICH. 0 ( Delay is 0 AS), 1 ( Delay is 1 AS) ;default 0. • WCEL: RACH_Tx_NB01min In case that a negative acknowledgement has been received by UE on AICH a backoff timer TBO1 is started to determine when the next RACH transmission attempt will be started. The backoff timer TBO1 is set to an integer number NBO1 of 10 ms time intervals, randomly drawn within an Interval 0 ≤ NB01min ≤ NBO1 ≤ NB01max (with uniform distribution). [0 ... 50]; default: 0. • WCEL: RACH_Tx_NB01max [0 ... 50]; default: 50. 100 Company Confidential

Outer Loop Power Control

OL PC is needed to keep the quality of the communication at the required level (BLER, SIR, BER,…) by setting the target (SIR) for the fast power control. It aims at providing the required quality: no worse, no better. Too high quality would waste capacity. It is needed in both UL and DL since there is Fast PC (Closed Loop or Inner Loop) in both UL and DL 101 Company Confidential

Outer Loop Power Control

In RADIO BEARER SETUP Message you can find the Target BLER (for the DL) For AMR and PS 128 = 1% BLER, CS T (VIDEO) = 0.1%, CS NT = 0.2% 102 Company Confidential

UL Outer Loop Power Control Algorithm

Case of Soft Handover

103 Company Confidential

UL Outer Loop Power Control Algorithm

104 Company Confidential

UL OL PC: BLER ÆEb/No Æ (Initial SIR Target, SIR Target Max, SIR Target Min)

105 Company Confidential

DL Outer Loop Power Control

DeltaSIR(1,2), DeltaSIR after (1,2),….. The adjustments of the SIR Target done by the UE is a proprietary algorithm that provides the same measured quality (BLER) as the quality target set by the RNC 106 Company Confidential

Fast Closed Loop (Inner) Power Control

107 Company Confidential

Fast Closed Loop (Inner) Power Control • UL (Near-Far Problem): UE1 and UE2 operate within the same frequency, separable at the base station only by their respective spreading codes. It may happen that UE1 at the cell edge suffers a path loss, say 70 dB above that of UE2 which is near to NodeB. If there were no mechanism for UE1 and UE2 to be power-controlled to the SAME level at the NodeB, UE2 could easily overshoot UE1 and thus a large part of the cell. Æ Power control tries to equalizes the Rx power per bit of all UE’s at NodeB. Since Fast Fading is uncorrelated between uplink and downlink (large freq separation between ul and dl bands in FDD) we can not use only a method based on Open Loop Power Control. Solution: Closed Loop PC: in UL the NodeB performs frequent (1.5 KHz) estimates of the received SIR and compares it to the SIR Target (calculated during Outer Loop PC). • DL: We do not have Near-Far Problem due to one-to-many scenario: all the signals within one cell originate from one NodeB to all mobiles. However it is desirable to provide a marginal amount of additional power to UE at the cell edge, as they suffer from increased other-cell-interference. 108 Company Confidential

DL Fast Closed (Inner) Loop Power Control Inner loop power control is also often called (fast) closed loop power control. It takes place between the UE and the Node B. We talk about UL inner loop power control, when the Node B returns immediately after the reception of a UE‘s signal a power control command to the UE. By doing so, the UE‘s SIR ratio is kept at a certain level (the details will be discussed later on in the course). DL inner loop power control control is more complex. When the UE receives the transmission of the Node B, the UE returns immediately a transmission power control command to the Node B, telling the Node B either to increase or decrease its output power for the UE‘s DPCH. The Node B‘s transmission power can be changed by 0.5, 1, 1.5 or 2 dB. 1 dB must be supported by the equipment. If other step sizes are supported or selected, depends on manufacturer or operator. The transmission output power for a DPCH has to be balanced for the PICH, which adds to the power step size. There are two downlink inner loop power control modes: • DPC_MODE = 0: Each timeslot, a unique TPC command is sent uplink. • DPC_MODE = 1: 3 consecutive timeslots, the same TPC command is transmitted. One reason for the UE to request a higher output power is given, when the QoS target has not been met. It requests the Node B to transmit with a higher output power, hoping to increase the quality of the connection due to an increased SIR at the UE‘s receiver. But this also increases the interference level for other phones in the cell and neighbouring cells. The operator can decide, whether to set the parameter Limited Power Increase Used. If used, the operator can limit the output power raise within a time 109 period. Company Confidential

DL Fast Closed (Inner) Loop PC Algorithm Every 1500 Hz (time slot) UE measures SIR= (RSCP/ISCP)×SF

110 Company Confidential

Downlink Inner Loop Power Control

TPC two modes

cell

DPC_MODE = 0

DPC_MODE = 1

unique TPC command per TS

same TPC over 3 TS, then new command TPCest per 1 TS / 3 TS

111 Company Confidential

UL Inner Loop Power Control SIRest

SIRtarget

time TC TCP T TC CP P = P= = =0 0 1 1

TPC ⇒ TPC_cmd

in FDD mode: 1500 times per second 112 Company Confidential

UL Fast Closed (Inner) Loop PC Algorithm

113 Company Confidential

UL Inner Loop Power Control Power Control Algorithm 1 is applied in medium speed environments. Here, the UE is commanded to modify its transmit power every timeslot. If the received TPC value is 1, the UE increases the transmission output at the DPCCH by ∆DPCCH, otherwise it decreases it by ∆DPCCH. The ∆DPCCH is either 1 or 2 dB, as set by the higher layer protocols. TPC values from the same radio link set represent one TLC_cmd. TPC_cmds from different radio link sets have to be weighted, if there is no reliable interpretation. Power Control Algorithm 2 (300 times/s) was specified to allow smaller step sizes in the power control in comparison to PCA1. This is necessary in very low and high speed environments. In these environments, PCA1 may result in oscillating around the target SIR. PCA2 changes only with every 5th timeslot, i.e. the TPC_cmd is set to 0 the first 4 timeslots. In timeslot 5, the TPC_cmd is –1, 0, or 1. For each radio set, the TPC_cmd is temporarily determined. This can be seen in the next figure. The temporary transmission power commands (TPC_temp) are combined as can be seen in the figure after the next one. Here you can see, how the final TPC_cmd is determined. 114 Company Confidential

UL Inner Loop Power Control Algorithms (1 and 2) • The optimum PC step size varies depending on the UE speed. For a given quality target, the best UL PC step size is the one that results in the lowest target SIR. With an update rate of 1500 Hz, a PC step size of 1dB can effectively track a typical Rayleigh fading channel up to Doppler frequency of about 55 Hz (30 Km/h). At higher speeds, up to about 80 Km/h, a PC step size of 2dB gives better results. • For speeds greater than 80 Km/h the inner loop PC can no longer follow the fades and just introduces noise into the UL transmission. This adverse effect on the UL performance could be reduced if a PC step size smaller than 1 dB was employed. Also, for UE speeds lower than about 3 Km/h where the fading rate of the channel is very small, a smaller step size is more beneficial. • Algorithm 1 is used when the UE speed is sufficiently low to compensate for the fading of the channel (PC step size should be 1 or 2 dB) • Algorithm 2 was designed for emulating the effect of using a PC step size smaller than 1 dB and can be used to compensate for the slow fading trend of the propagation channel rather than rapid fluctuations. It performs better than Alg 1 when the UE moves faster than 80 Km/h or slower than 3 Km/h. The UE does not change its transmission power until it has received 5 115 consecutive TPC commands. Company Confidential

UL Inner Loop Power Control algorithms for processing power control commands TPC_cmd

PCA1

PCA2

TPC_cmd for each TS TPC_cmd values: +1, -1 step size ∆ TPC: 1dB or 2dB

TPC_cmd for 5th TS TPC_cmd values: +1, 0, -1 step size ∆ TPC: 1dB

UL DPCCH power adjustment: ∆DPCCH = ∆ TPC × TPC_cmd PCA2 0

PCA1

PCA2

≈ 3Rayleigh fading can be compensated ≈ 80

km/h 116

Company Confidential

UL Inner Loop Power Control Algorithm 1 Example: reliable transmission

Cell 3 TPC3 = 1 ⇒ TPC_cmd = -1

TPC1 = 1

Cell 1

TPC3 = 0

Cell 2 117 Company Confidential

UL Inner Loop Power Control Algorithm 2 (Part 1)

TPC = 1 TPC = 1 TPC = 1 TPC = 1 TPC = 1 TPC = 1 TPC = 0 TPC = 1 TPC = 0 TPC = 1 TPC = 0 TPC = 0 TPC = 0 TPC = 0 TPC = 0

TPC_temp 0 • 0 0 0 • 1 0 0 • 0 0 0 0 0 0 0 -1

if all TPC-values = 1 ⇒ TPC_temp = +1 if all TPC-values = 0 ⇒ TPC_temp = -1 otherwise ⇒ TPC_temp = 0

118 Company Confidential

UL Inner Loop Power Control Algorithm 2 (Part 2) Example:

N = 3 cells

TPC_temp1 TPC_temp2 TPC_temp3

1 N TPC_tempi ∑ N i=1

-1 TPC_cmd =

-0.5 -1

0

1

0.5

0 Company Confidential

1

119

Part VI Dedicated Physical Channels

120 Company Confidential

Downlink Dedicated Physical Channel (DPCH) The downlink DPCH is used to transmit the DCH data. Control information and user data are time multiplexed. The control data is associated with the Dedicated Physical Control Channel (DPCCH), while the user data is associated with the Dedicated Physical Data Channel (DPDCH). The transmission is organised in 10 ms radio frames, which are divided into 15 timeslots. The timeslot length is 2560 chips. Within each timeslot, following fields can be found: • Data field 1 and data field 2, which carry DPDCH information • Transmission Power Control (TPC) bit field • Transport Format Combination Indicator (TFCI) field, which is optional • Pilot bits The exact length of the fields depends on the slot format, which is determined by higher layers. The TFCI is optional, because it is not required for services with fixed data rates. Slot format are also defined for the compressed mode; hereby different slot formats are in used, when compression is archived by a changed spreading factor or a changed puncturing scheme. The pilot sequence is used for channel estimation as well as for the SIR ratio determination within the inner loop power control. The number of the pilot bits can be 2, 4, 8 and 16 – it is adjusted with the spreading factor. A similar adjustment is done for the TPC value; its bit numbers range between 2, 4 and 8. The spreading factor for a DPCH can range between 4 and 512. The spreading factor 121 can be changed every TTI period. Company Confidential Superframes last 720 ms and were introduced for GSM-UMTS handover support.

Downlink Dedicated Physical Channel (DPCH) Superframe = 720 ms Radio Frame Radio Frame Radio Frame 0 1 2

Radio Frame 71

10 ms Frame Slot 0

Slot 1

Slot 2

Data 1 bits

TPC bits

DPDCH • 17 different slot formats • Compressed mode slot format for changed SF & changed puncturing

Slot 14

TFCI bits

Data 2 bits

Pilot bits

(optional)

DPCCH

2,4,8 bits Company Confidential

DPDCH

DPCCH

2,4,8,16 bits (SIR estimation) 122

Downlink Dedicated Physical Channel (DPCH) Following features are supported in the downlink: • Blind rate detection, and • Discontinuous transmission. Rate matching is done to the maximum bit rate of the connection. Lower bit rates are possible, including the option of discontinuous transmission. Please note, that audible interference imposes no problem in the downlink, since Common Channels have continuous transmission.

Multicode usage: Several physical channels can be allocated in the downlink to one UE. This can occur, when several DPCH are combined in one CCTrCH in the PHY layer, and the data rate of the CCTrCH exceeds the maximum data rates allowed for the physical channels. Then, on all downlink DPCHs, the same spreading factor is used. Also the downlink transmission of the DPCHs takes place synchronous. One DPCH carries DPDCH and DPCCH information, while on the remaining DPCHs, no DPCCH information is transmitted. But also in the case, when several DPCHs with different spreading factors are in use, the first DPCH carries the DPCCH information, while in the remaining DPCHs, this information is omitted (discontinuous transmission). Multicode usage is not implemented in RAN1.

Company Confidential

123

Physical Layer Bit Rates (Downlink) Spreading factor 512 256 128 64 32 16 8 4 4, with 3 parallel codes

Channel symbol rate (ksps) 7.5 15 30 60 120 240 480 960 2880

Channel bit rate (kbps) 15 30 60 120 240 480 960 1920 5760

DPDCH channel bit rate range (kbps) 3–6 12–24 42–51 90 210 432 912 1872 5616

Maximum user data rate with ½rate coding (approx.) 1–3 kbps Half rate speech 6–12 kbps Full rate speech 20–24 kbps 45 kbps 105 kbps 128 kbps 215 kbps 456 kbps 384 kbps 936 kbps 2.8 Mbps 2 Mbps

• The number of orthogonal channelization codes = Spreading factor 124 Company Confidential

Downlink Dedicated Physical Channel (DPCH) maximum bit rate

TS

discontinuous transmission with lower bit rate

TS

TS

TS

TS

Multicode usage: DPCH 1 TS

TS

TS DPCH 2

TS

TS

TS DPCH 3 125 Company Confidential

• Power offsets • TFCS • DL DPCH slot format • FDD DL TPC step size

Power Offsets for the DPCH

NBAP: RADIO LINK SETUP REQUEST

DCH Data Frame

Node B

Iub

Uu

RNC

P0x: 0..6 dB step size: 0.25 dB

PO2 Data 1 bits

UE

TPC bits

TFCI bits (optional)

PO3

PO1

Pilot bits

Data 2 bits 126

Company Confidential

Nokia Parameters Related to DPCHs • RNC: PowerOffsetDLdpcchPilot The parameter defines the power offset for the pilot symbols in relative to the data symbols in dedicated downlink physical channel [0 … 6 dB]; step size 0.25 dB; default: 3 dB for 12.2 kbps • RNC: PowerOffsetDLdpcchTpc, The parameter defines the power offset for the TPC symbols relative to the data symbols in dedicated downlink physical channel [0 … 6 dB]; step size 0.25 dB; default: 3 dB for 12.2 kbps • RNC: PowerOffsetDLdpcchTfci, The parameter defines the power offset for the TFCI symbols relative to the data symbols in dedicated downlink physical channel. [0 … 6 dB], step size 0.25 dB; default: 3 dB for 12.2 kbps

127 Company Confidential

Uplink Dedicated Physical Channels The uplink dedicated physical channel transmission, we identify two types of physical channels: Dedicated Physical Control Channel (DPCCH), which is always transmitted with spreading factor 256 (3840/256=15Ksps=15Kbps). Following fields are defined on the DPCCH: - pilot bits for channel estimation. Their number can be 3, 4, 5, 6, 7 or 8. - Transmitter Power Control (TPC), with either one or two bits - Transport Format Combination Indicator (TFCI), which is optional, and a - Feedback Indicator (FBI). Bits can be set for the closed loop mode transmit diversity and site selection diversity transmission (SSDT) 6 different slot formats were specified for the DPCCH. Variations exist for the compressed mode. Dedicated Physical Data Channel (DPDCH), which is used for user data transfer. Its spreading factor ranges between 4 and 256. 7 different solt formats are defined, which are set by the higher layers. The DPCCH and DPDCH are combined by I/Q code multiplexing with each multiframe. Multicode usage is possible. If applied, additonal DPDCH are added to the uplink transmission, but no additional DPCCHs! The maximum number of DPDCH is 6; when more than one DPDCH is used (Multicodes) they all use SF = 4. The transmission itself is organised in 10 ms radio frames, which are divided into128 15 timeslots. The timeslot length is 2560 Company chips. Confidential

Uplink Dedicated Physical Channels Superframe = 720 ms Radio Frame Radio Frame Radio Frame 0 1 2

Radio Frame 71

10 ms Frame Slot 0

Slot 1

Slot 2

DPDCH DPCCH

• 7 different slot formats

Slot 14

Data 1 bits TFCI bits

Pilot bits • 6 different slot formats • Compressed mode slot format for changed SF & changed puncturing

(optional)

Feedback Indicator for • Closed loop mode transmit diversity, & • Site selection diversity transmission (SSDT) Company Confidential

FBI bits

TPC bits

129

Discontinuous Transmission and Power Offsets Discontinuous transmission (DTX) is supported for the DCH both uplink and downlink. If DTX is applied in the downlink – as it is done with speech – then 3000 bursts are generated in one second. (1500 times the pilot sequence, 1500 times the TPC bits) This causes two problems: • Inter-frequency interference, caused by the burst generation. At the Node B, the problem can be overcome with exquisite filter equipment. This filter equipment is expensive and heavy. Therefore it cannot be applied in the UE. The UE‘s solution is I/Q code multiplexing, with a continuous transmission for the DPCCH. DPDCH changes can still occur, but they are limited to the TTI period. The minimum TTI period is 10 ms. The same effects can be observed, then the DPDCH data rate and with it its output power is changing. • 3000 bursts causes audible interference with other equipment – just see for example GSM. By reducing the changes to the TTI period, the audible interference is reduced, too. Determination of the power difference between the DPCCH and DPDCH I/Q code multiplexing is done in the uplink, i.e. the DPCCH and DPDCH are transmitted with different codes (and possible with different spreading factors). Gain factors are specified: βc is the gain factor for the DPCCH, while βd is the gain factor for the DPDCH. The gain factors may vary for each TFC. There are two ways, how the UE may learn about the gain factors: • The gain factors are signalled for each TFC. If so, the nominal power relation Aj between the DPDCH and DPCCH is βd/βc. 130 • The gain factor is calculated based on reference TFCs. Company Confidential

Discontinuous Transmission and Power Offsets

DPDCH DPCCH

TTI

DPDCH DPDCH DPCCH

DPCCH

TTI

TTI

UL DPDCH/DPCH Power Difference: two methods to determine the gain factors: • signalled for each TFCs • calculation based on reference TFCs

Nominal Power Relation

Aj=

βd βc

DPDCH

=

Company Confidential

DPCCH 131

Initial Uplink DCH Transmission When we look to the PRACH, we can see, that a preambles were used to avoid UEs to access UTRAN with a too high initial transmission power. The same principle is applied for the DPCH. After PRACH procedure the UE transmits between 0 to 7 radio frames only the DPCCH uplink (the period is called DPCCH power control Preamble), before the DPDCH is code multiplexed. The number of radio frames is set by the higher layers (RRC resp. the operator). Also for this period of time, only DPCCH can be found in the downlink. The UE can be also informed about a delay regarding RRC signalling – this is called SRB delay, which can also last 0 to 7 radio frames. The SRB delay follows after the DPCCH preamble. How to set the the transmission power of the first UL DPCCH preamble? Its power level is DPCCH_Initial_power = – CPICH_RSCP + DPCCH_Power_offset The DPCCH Power Offset is retrieved from RRC messages. It’s value ranges between –164 and –6 dB (step size 2 dB). CPICH_RSCP is the received signal code power on the P-CPICH, measured by the UE.

132 Company Confidential

Initial Uplink DCH Transmission DPCCH only

DPCCH & DPDCH

reception at UE

transmission at UE

T0 0 to 7 frames for power control preamble DPCCH only, always based on PCA1

DPCCH & DPDCH PCA based on RRC

DPCCH_Initial_power = – CPICH_RSCP + DPCCH_Power_offset 133 Company Confidential

Radio frame timing and access slot timing of downlink physical channels Primary SCH Secondary SCH Any CPICH P-CCPCH k:th S-CCPCH

Radio framewith (SFN modulo 2) = 0

Radio framewith (SFN modulo 2) = 1

τS-CCPCH,k τPICH

PICH for k:th S-CCPCH AICH access slots

#0

#1

#2

#3

#4

#5

#6

#7

#8

#9

#10

#11

#12

#13

#14

Any PDSCH n:th DPCH HS-SCCH Subframes

τDPCH,n

Subframe Subframe Subframe Subframe Subframe #0 #1 #2 #3 #4

10 ms

10 ms

Company Confidential

134

Part VII WCDMA Planning

135 Company Confidential

Radio Network Planning Process DEFINITION System Dimensioning Requirements and strategy for coverage, quality and capacity, per service

PLANNING and IMPLEMENTATION Coverage Planning and Site Selection Path loss prediction Coverage optimisation

O&M

Capacity Optimisation

Network Optimisation

Traffic distribution

Survey measurements

Pilot Power Soft handover Blocking objectives

Statistical performance analysis

Cell isolation optimisation

136 Company Confidential

Planning issues • Planning should meet current standards and demands and also comply with future requirements. • Uncertainty of future traffic growth and service needs. • High bit rate services require knowledge of coverage and capacity enhancements methods. • Real constraints – Coexistence and co-operation of 2G and 3G for old operators. – Environmental constraints for new operators. • Network planning depends not only on the coverage but also on load.

Objectives of Radio network planning • Capacity: – To support the subscriber traffic with sufficiently low blocking and delay. • Coverage: – To obtain the ability of the network ensure the availability of the service in the entire service area. • Quality: – Linking the capacity and the coverage and still provide the required QoS. • Costs: – To enable an economical network implementation when the service is established and a controlled network expansion during the life cycle of the network. 137 Company Confidential

Planning methods • Preparation phase – Defining coverage and capacity objectives – Selection of network planning strategies – Initial design and operation parameters • Initial dimensioning – First and most rapid evaluation of the network elements count and capacity of these elements – Offered traffic estimation – Joint capacity coverage estimation • Detailed planning – Detailed coverage capacity estimation – Iterative coverage analysis – Planning for codes and powers • Optimization – Setting the parameters • Soft handover • Power control • Verification of the static simulator with the dynamic simulator

138 Company Confidential

A strategy for dimensioning • • • • •

Plan for adequate load and number of sites. Enable optimized site selection. Avoid adding new sites too soon. Allow better utilization of spectrum. Recommended load factor 30- 70 %

139 Company Confidential

Dimensioning process

140 Company Confidential

Capacity&Coverage Trade Off •The coverage for a WCDMA system is generally limited by the uplink. This is because the maximum output power of the mobile is lower than for the base station, so the base station can reach longer than the mobile can. •Capacity is generally limited by the downlink. This is because better receiver techniques can be used in the base station than in the mobile. Since most forecasts predict an asymmetric load where the users download data to a larger extent than sending, the downlink will be most important from a capacity point of view. •Capacity and coverage is closely related in a WCDMA system. When traffic increases, the level of interference in the system increases. To compensate for this, the mobile has to increase its output power in order to defeat the increased noise, or in already at max power, make the connection closer to the base station. • Due to the increase of traffic, the effective cell area has shrunk. This behavior is known as cell breathing. In an FDMA or TDMA-system this problem does not arise, since coverage and capacity is largely independent. •To reduce cell breathing interference margins are included when dimensioning the network, which has the effect of increasing site density.

141

Company Confidential

Coverage Limited Uplink •

Another way to reduce cell breathing would be to add a frequency, which would mean that the users could be spread over two or more carriers. Since the different carriers are not interfering with each other, the interference level is reduced, and an increase in capacity or coverage is achieved

•

When making the initial design, the aim is to provide a certain capacity, or service level, over an area. One design strategy could be to design a very low-density network, capable of providing low capacity over a wide area.

•

This would reduce the number of base stations as compared to building for higher capacity. Since the cost of base stations are a large part of the cost of building a network, minimizing the number of base stations are important.

•

On the other hand, it is important to be able to provide attractive services to the customers. This could be difficult if not enough bandwidth is available. Building less dense means that the maximum distance between the mobile and base station is increased, which is the same as allowing a higher maximum path loss between the two.

•

A higher path loss between the mobile and the base station can be tolerated if the interference is decreased. If the interference in a cell were reduced by a certain amount of dB, the maximum allowed path loss would increase by the same amount. 142 Company Confidential

Coverage Limited Uplink •Using a propagation model like for example Okumura-Hata, it is possible to convert a change of the interference level into a changed site density, compared to a reference case. •Table below shows the change in number of sites if the interference margin in the link budget is changed. A negative dB value means that the link budget is worse compared to the reference case, and thus more sites are needed.

143 Company Confidential

Uplink Load Factor Interference degradation margin: describes the amount of increase of interference due to multiple access . It is reserved in the link budget. Can be calculated as the Noise Rise: the ratio of the total received power Itotal to the Noise Power PN

Noise Rise =

I total 1 1 = = N PN 1 − ∑ j =1 L j 1 − ηUL

Where Load Factor η ULis :

ηUL = ∑ j =1 L j , L j is the load factor of one connection N

The uplink load factor can be written as

ηUL = (1 + i ) ⋅ ∑ j =1 L j = (1 + i ⋅ N

NS

ζ

) ⋅ ∑ j =1 N

1 W 1+ ( Eb / N O ) j ⋅ R j ⋅υ j

Noise Rise (dB) is equal to - 10 ⋅ log10 (1 − ηUL )

Where ηUL ∈ [0,1]

144 Company Confidential

Uplink Load Factor Definitions

Recommended Values

N

Number of users per cell

υj

Activity Factor of user j at physical layer

0.67 for speech

Eb/No

Signal energy per bit divided by noise spectral density that is required to meet a predefined BLER. Noise includes both thermal and interference

Dependent on service, bit rate, mulitpath, fading channel, receive antenna diversity, mobile speed, etc

W

WCDMA chip rate

3.84 Mcps

Rj

Bit Rate of user j

Dependent on service

ζ

Sectorisation Gain

1 Sector (Omni): 1; 3 Sectors (90°): 2.57; 3 Sectors (65°): 2.87; 3 Sectors (33°): 2.82 4 Sectors (90°): 3.11; 6 Sectors (65°): 4.70

NS

Number of Sectors

i

Other cell to own cell interference ratio seen by the base station receiver

Macro Cell with omni antennas: 55%. Macro Cell with 3 sectors: 65% 145

Company Confidential

Noise Rise (dB)

Uplink Noise Rise as a Function of Throughput 12 11 10 9 8 7 6 5 4 3 2 1 200

400

600

800

1000

1200

1400

1600

Throughput (Kbps) Voice (12.2 Kbps) 144 Kbps 146 Company Confidential

Coverage Limited Uplink • • •

• •

• •

For voice services a typical noise rise would be between 1-3 dB, which corresponds to a throughput between 150 kbps and 375 kbps. A network is designed for a certain throughput. After some time that throughput is reached, and as a result the noise rise rises over the design value. The choice is then to either increase site density, or add more frequencies. Adding a frequency has its own set of problems, most notably that soft handover does not work between frequencies. This problem is less of an issue if new frequencies are added to a number of sites over a wider area. The mobile can then move freely on the frequency it has been assigned, and the probability of making a hard inter-frequency handover is reduced Assume that traffic increases so that the actual noise rise is 4 dB, 1 dB above the design level. The noise figure needs to be improved, for example down to 2 dB, to improve quality and make room for future capacity demands. In other words, the average throughput per cell needs to be reduced. Building more sites, or adding another frequency can do this. Adding a second frequency would half the throughput for each cell and carrier. For a 4 dB noise rise the throughput is 450 kbps according to the graph. A new throughput of 450/2 kbps=225 kbps per carrier gives a noise rise of 1.5 dB, an improvement of 2.5 dB. A 2.5 dB lower allowable path loss corresponds roughly to 40% more sites, that is, The cost of building these sites can then be said to be the value of having one extra frequency. Adding a second and a third frequency follows the same pattern, with a slight difference. The relative decrease in noise rise will be lower. When a third frequency is added the traffic is spread over three 147 carriers, and reduced with a third for each frequency. Company Confidential

Coverage Limited Uplink It is also possible to do the other way around, that is, build sites less dense to start with. This saves money in the roll out phase, but could cause problems if high capacity is needed in the future. Using figures from the example above, assume a design for a maximum throughput of 375 kbps for one carrier, which corresponds to a noise rise of 3 dB. Using two carriers gives a throughput per carrier of 375/2 kbps=190 kbps, which corresponds to a noise rise of 1.3 dB. The saving is 2.7 dB, which converts to roughly 70% of the original number of sites is needed. This is the same as each site covers approximately 1.4 times the area of the original one carrier site. Uplink Coverage of Different Bit Rates 3.5 3 2.5

Range [km]

•

2 1.5 1 0.5 0 32 kbps

64 kbps

144 kbps

384 kbps 1024 kbps 2048 kbps

Suburban area with 95% outdoor location probability Company Confidential

148

Downlink Load Factor η DL = ∑ j =1υ j ⋅ N

( Eb / N O ) j W Rj

[

⋅ (1 - α j ) + i j

]

Noise Rise over therm al noise due to multiple access interferen ce is equal to - 10 ⋅ log 10 (1 − η DL ) Where η DL ∈ [0,1] Definitions N

υj

Recommended Values

Number of users per cell Activity Factor of user j at physical layer

0.58 for speech

Eb/No

Signal energy per bit divided by noise spectral density that is required to meet a predifined BLER. Noise includes both thermal and interference

Dependent on service, bit rate, mulitpath, fading channel, receive antenna diversity, mobile speed, etc

W

WCDMA chip rate

3.84 Mcps

Rj

Bit Rate of user j

Dependent on service

αj

Orthogonality of channel of user j

ij

Dependent on the multipath propagation 1: fully orthogonal 1-path channel 0: no orthogonality ITU Vehicular A channel: ~ 50% ITU Pedestrian A channel: ~ 90% ij Ratio of other cell to own cell base station power, Each user sees a different , depending on received by user j its location in the cell and log-normal shadowing. Macro Cell with omni antennas: 149 55%. Macro Cell with 3 sectors: 65% Company Confidential

Downlink Load Factor •

•

•

Compared to the uplink load equation, the most important new parameter is α j , which represent the orthogonality factor in the downlink. WCDMA employs orthogonal codes in DL to separate users, and without multipath propagation the orthogonality remains when the base station signal is received by the mobile. The DL load factor exhibits very similar behavior to the UL load factor, in the sense that when approaching unity, the system reaches its pole capacity and the noise rise over thermal noise goes to infinity For downlink dimensioning, it’s important to estimate the total amount of base station transmission power required. This is based on average transmission power for user

N rf ⋅ W ⋅ L ⋅ ∑ j =1υ j N

BS _ TxPw =

(Eb

(W

No ) j Rj )

1 − η DL

Where N rf is the noise spectral density of the mobile N rf = k ⋅ T + NF = −174dBm + NF (assuming T = 290K) k is the Boltzmann constant of 1.381⋅10-23 J / K , NF is mobile Noise Figure (5 - 9 dB) 150 Company Confidential

Downlink Common Channels •

Part of the downlink power has to be allocated for the common channels that are transmitted independently of the traffic channels Downlink common channels

Relative to CPICH Activity Average Power allocation with 20W max Power

CPICH

0 dB

100%

2.0 W

P-SCH

-3 dB

10%

0.1 W

S-SCH

-3 dB

10%

0.1 W

P-CCPCH

-5 dB

90%

0.6 W

PICH

-8 dB

100%¹

0.3 W

AICH

-8 dB

100%¹

0.3 W

S-CCPCH

0 dB²

10%³

0.2 W

Almost 50% is for CPICH

Total Common channels Power

3.6 W

Remaining power for traffic channels

20-3.6 = 16.4 W

¹ Worst case; ² Depends on the FACH bit rate; ³ Depends on PCH and FACH traffic 151

Company Confidential

Relation of Uplink and Downlink Load 100 90

• Downlink load is always higher than uplink load due to: – asymmetry in user traffic – different Eb/No values in uplink and downlink – orthogonality in downlink – overhead due to softhandover

80

DL Load [%]

70 60

Increasing asymmetry

50 40 30 20 10 0 0

10

20

30

40

50

UL Load [%]

152 Company Confidential

Capacity Limited Downlink • •

• •

• •

•

As the demand for downlink capacity increases, there are several different ways of increasing capacity. The most common ways are adding more frequencies and power amplifiers, and introducing transmit diversity Upgrading capacity in the ways just mentioned is of course dependant on the base station equipment being able to handle it. It is reasonable to assume that as the capacity demand increases, the equipment vendors will produce equipment that can handle it Assume an initial base station configuration of one 20W power amplifier per sector, one carrier per sector and three sectors per site. This is called the baseline configuration, and has a baseline capacity The first step to upgrade the capacity is to add a second frequency. This gives a capacity increase of 80%. The reason why the increase is not 100% is that the power amplifier only can deliver 20W, which has to be split between the two frequencies, making the output 10W per carrier. The second step could be to add a second 20W power amplifier (restoring the power per frequency to 20W) and introduce transmit diversity. With these two upgrades the capacity now is 180% compared to the baseline. Adding a third frequency would decrease the output power to 13 W per carrier, but the extra carrier would still mean a capacity increase of 290% compared to the baseline If there are no more frequencies available, changing the power amplifiers from two 20W to two 40W will give a modest capacity increase, making the increase compared to baseline 320%. Adding a fourth frequency and at the same time changing out the two 20W power amplifiers to two 40W amplifiers, if that has not been done before, gives a capacity increase 460% compared to the baseline. 153 Company Confidential

Capacity Limited Downlink •

• • •

Upgrading the power amplifier restores the power per frequency to 20W, the same as the baseline case. With the stronger PA’s there is power to add a fifth and a sixth carrier. This would give capacities of 550% respectively 680% compared to the baseline Using two PA’s means that no modification to the antenna system is required. Adding a third PA means that either a combiner, or an extra antenna needs to be used. A combiner typically has a 3dB insertion loss, offsetting the gain achieved Adding a third antenna is complicated from a site-engineering point of view. An extra feeder cable is needed, and adding an extra antenna could be difficult since it means renegotiating the agreement with the house owner. With a third PA the 6 frequencies is transmitting at 20W, giving a 740% increase gain compared to the baseline capacity.

Example upgrade path

154 Company Confidential

Typical Pathlosses for different Bearer Services Low Data Scenario Low Asymmetry Scenario 165,00

Pathloss [dB]

better coverage

160,00

Speech 12,2k UL Pathloss RT Data 14k UL Pathloss RT Data 64k UL Pathloss NRT Data 144k UL Pathloss NRT Data 384k UL Pathloss DL Pathloss

155,00

150,00

Coverage is uplink limited

145,00

Capacity is downlink limited

140,00 0

10

20

30

40

50

60

70

80

UL Load

155 Company Confidential

Part VIII WCDMA Link Budget

156 Company Confidential

WCDMA Link Budget

157 Company Confidential

WCDMA Link Budget

158 Company Confidential

WCDMA Link Budget

159 Company Confidential

WCDMA Link Budget

160 Company Confidential

WCDMA Link Budget

161 Company Confidential

WCDMA Link Budget

162 Company Confidential

WCDMA Link Budget

163 Company Confidential

WCDMA Link Budget

164 Company Confidential

WCDMA Link Budget

165 Company Confidential

WCDMA Link Budget

166 Company Confidential

WCDMA Link Budget

167 Company Confidential

WCDMA Link Budget

168 Company Confidential

WCDMA Link Budget

169 Company Confidential

WCDMA Link Budget

170 Company Confidential

WCDMA Link Budget – Cell Sizes •Output of Link Budget is MAPL (Maximum Allowed Path Loss) based on different: - Clutter types (Dense Urban, Urban, Sub-Urban, Rural) - Services (AMR, PS64, CS64, PS128, PS384,…) - Indoor/Outdoor - Area Location Probability - Mobile speed: Pedestrian/Vehicular •Given an area to be covered (Km²) the cell count has to be performed based on Cell Area (Å Cell Radius) •Cell Radius can be calculated using Propagation models (Cost231, HokumuraHata, Walfish-Ikegami,…) •The models need as input: •MAPL •UE antenna height •NodeB antenna height •Frequency •Clutter correction factors

171 Company Confidential

WCDMA Link Budget – Cell Count r = Cell Radius r Surface of a tri-sectorial cell :

ACell

3 2 r =3 2

Number of Sites = Number of Cells /3 Intersite Distance = 1.5*r Example: r = 0.409 km Acell = 0.432 km2 Stotal = 100 km² Number of Tri-secotrial sites = 100/0.432 ≈ 230

172 Company Confidential

Part IX Coverage-Capacity enhancement

173 Company Confidential

Coverage Improvement Alternatives • Mast head amplifier – basic solution for optimized uplink performance – compensates feeder cable loss – supported by Nokia's base stations – can be used together with Smart Radio Concept

• 6 sectored site – utilizing narrowbeam antennas – ~ 2 dB better antenna gain than in 3 sectored site • Nokia Smart Radio Concept, SRC – 4-branch uplink diversity

174 Company Confidential

Capacity Improvement Alternatives • 6 sectored site – ~ 80% capacity gain compared to 3 sectors (not 100% due to inter-sector interference) • More carriers (frequencies) per sector – doubling the amount of carriers with power splitting gives roughly 60% more capacity • Smart Radio Concept – transmit diversity

175 Company Confidential

Smart Radio Concept Uplink coverage – 4-branch diversity reception per sector – Maximal ratio baseband combining of 4 uplink signals forms a beam

dB 10

Received signal power

5 0

Downlink capacity upgrade – Upgrade transmit diversity when needed

RX

+ TX

-5 -10 SRC Rx diversity -15 0 0.5 1

1.5 2 2.5 Seconds, 3km/h

RX RX RX + TX WCDMA Transceiver

Combined received signal 176

Company Confidential

144 kbps Coverage / Capacity in Macro Cells Max. allowed path loss [dB] 170

Downlink load curve

165 Better 160 coverage 155 150 145

Coverage is uplink limited Capacity is downlink limited Uplink load curve with RX diversity for 144 kbps

100 200 300 400 500 600 700 800 900 1000110012001300 Load per sector [kbps] 177

Company Confidential

Nokia Smart Radio Concept Phase 1: Increase Uplink Coverage Max. allowed path loss [dB] 170 165 160

Uplink load curve with SRC

2.5-3.0 dB coverage improvement with SRC

155 150 145

Uplink load curve without SRC 100 200 300 400 500 600 700 800 900 1000110012001300 Load per sector [kbps]

178

Company Confidential

Nokia Smart Radio Concept Phase 2: Increase Downlink Capacity Max. allowed path loss [dB] 170 Downlink with TX diversity, 20W per branch

165 160 155 150

Downlink 20W no diversity

70% increase in capacity

145 100 200 300 400 500 600 700 800 900 1000110012001300 Load per sector [kbps]

179

Company Confidential

Coverage : 30 % less sites with SRC Sites / km2 0.3 0.25

2.5 - 3.0 dB gain corresponds to 30% less sites with SRC

0.2 0.15 0.1 0.05 0

3-sector (rx div)

3-sector (SRC) 180 Company Confidential

Capacity Upgrade with Smart Radio Concept • No changes to antennas or antenna cables • All these capacity upgrades within one Ultrasite cabinet Speech Erlang per site 350

Cost / Erlang is decreasing with capacity upgrades

300 250 200

Add tx diversity + take 2nd frequency into use

150 100 50 0 20W

2x10W + 2x10W

Downlink power per sector Company Confidential

181

Capacity Optimisation The impact of MHA, SRC & 6 -sector site 3G Radio Network Planning case study Assumptions: •The geographic area under study is defined by the suburban area of London •The site's location was given, antennas´ directions are the same as the DCS network. Two antenna type has been used, 60 and 90 degrees horizontal opening •1800MHz measurements provided. Assumption that narrow band 1800MHz propagation is representative of wideband 2GHz propagation •15dB of building penetration loss included in the link budget for Indoor Coverage. •Multiple simulation runs. MS positions and slow fading changed for each run

182 Company Confidential

Area under Investigation Suburban area of London 12km by 11km Intended to be representative of suburban areas across the UK Morphology analysis Morphology

Percentage Area

Suburban Open/Fields Open in Urban Industrial Roads in Urban Forest Urban Water

65.2% 13.7% 10.1% 6.3% 2.2% 2.0% 0.5% 0.1%

183 Company Confidential

Radio Network Configuration 51 sites (3 sector) existing 1G and 2G sites, plus sites to be acquired prior to 3G Link level simulations used to define Eb/No requirements, SHO Gain Vehicular A channel assumed

Parameter Assumptions Parameter Max. transmit power Max. power per link Min. transmit power per link CPICH power Common channel power Cable/connector loss Soft handover window RF carriers available Slow fading standard dev. Maximum uplink load

Value 43dBm not limited not limited 30dBm 30dBm 3dB 5dB 1 8dB 50%

184 Company Confidential

Antenna Configuration 1G and 2G antenna list

3G antenna list

60° antenna x 56

60° antenna x 56

85° antenna x 97

90° antenna x 97

Differences in elec. tilt compensated with mech. tilt Antenna Type

Horizontal Beamwidth

Vertical Beamwidth

Electrical Downtilt

Antenna Gain

741415 CS72138

60° 90°

7° 7°

0° 2°

18dBi 16.5dBi

741415

CS72138 Company Confidential

185

Traffic Modeling Priority placed on modeling traffic services separately

Uniform distribution of mobile terminals System loaded to maximum capability

12.2kbps speech 64kbps data 144kbps data

fixed uplink load limit fixed BTS power capability Link level simulations used to define Eb/No requirements, SHO Gain

Symetric data services

Parameter

12.2 kbps voice

Max. transmit power Min. transmit power Antenna height Antenna gain Body loss Uplink bit rate Downlink bit rate Uplink activity factor Downlink activity factor Mobile speed

21 dBm -50 dBm 1.5 m 0 dBi 3 dB 12.2 kbps 12.2 kbps 0.67 0.67 50 km/hr

Service 64 kbps data

144 kbps data

21 dBm -50 dBm 1.5 m 0 dBi 0 dB 64 kbps 64 kbps 1 1 3 km/hr

21 dBm -50 dBm 1.5 m 2 dBi 0 dB 144 kbps 144 kbps 1 1 3 km/hr

MS Numbers Distrib. Supp. 12.2kbps speech 15000 ~5400 64kbps data

5000

~1100

144kbps data

1500

~500 186

Company Confidential

Benchmark Results MHA, SRC, 6 Sector not included

Uplink limited

Only coverage and capacity presented here Service 12.2kbps Speech 64kbps Data 144kbps Data

Uplink limited

Mean 99.83 98.54 96.74 88.05 70.05 59.71

100 6

0

0 0 30 60 Number of 12.2kbps speech users

Percentage of Cells

Indoor

Service of the Probe Mobile Speech 64kbps Data 144bps Data Speech 64kbps Data 144bps Data

Number of Cells

Outdoor

Capacities network per cell 5074 33.2 5336 34.9 966 6.3 1100 7.2 470 3.1 501 3.3

12

Depends upon polygon Envir.

Envir. Outdoor Indoor Outdoor Indoor Outdoor Indoor

187 Company Confidential

Impact of MHA MHA introduced at all sites Improves uplink power budget Improved Example indoor speech: 88Æ 93% indoor 64kbps data: 70Æ 79% indoor 144kbps data: 60Æ 71%

Trend of results as expected

Remains approximately the same uplink and downlink approximately balanced 188 Company Confidential

Impact of SRC (rx only) 2 scenarios SRC introduced at all sites SRC introduced at TACS sites only Reduces uplink Eb/No target Improved speech by 9% 64kbps data by 11% 144kbps data by 30%

Improved indoor speech: 88Æ 92% indoor 64kbps data: 70Æ 77% indoor 144kbps data: 60Æ 68%

Becomes limited by BTS tx power Observations: Once downlink limited, soft handover window has great impact upon capacity

Remains uplink limited

Introducing SRC at TACS sites only, increases capacity of surrounding sites 189 Company Confidential

Impact of SRC (rx & tx) Tx and Rx SRC introduced at all sites Reduces uplink and downlink Eb/No targets Further Improved Example: outdoor speech no SRC Æ 5000 users rx SRC Æ 5800 users (+15%) rx&tx SRC Æ 7500 users (+49%)

Tx SRC offers no coverage improvement over Rx SRC Coverage remains uplink limited

190 Company Confidential

Impact of 6 Sectors 2 scenarios 6 Sector introduced at all sites 6 Sector introduced at TACS sites only 33º beam width antennas Æ increased gain Doubled Example, outdoor speech, 2500Æ 5100 users 64kbps data, 440Æ 950 users 144kbps data, 230Æ 450 users

Usual message for 6S: capacity improves by less than a factor of 2 due to increased SHO & inter-cell interference

Improved Example, indoor speech: 85Æ 93% indoor 64kbps data: 65Æ 80 % indoor 144kbps data: 50Æ 70 %

Not true in this case due to antenna pattern selected: reduced SHO and inter-cell interference

Company Confidential

191

Part X WCDMA/GSM Co-siting issues

192 Company Confidential

Antenna System Co-siting

• GSM 900 / GSM 1800 shared antenna lines by diplexers/triplexers • GSM 900 / GSM 1800/WCDMA multi band antennas

193 Company Confidential

Antennas: WCDMA/GSM Co-site Shared antenna lines

Antenna 1:

Antenna 2:

GSM 900 / 1800

WCDMA X-pol

GSM 900/1800 antennas: 3 pcs

Dual Band X- pol

• GSM 900 / GSM 1800 / WCDMA triplexers

Shared antennas

• Dual Band GSM 900 / WCDMA • Dual Band GSM 1800/WCDMA • Triple Band 900/1800/WCDMA

3 sector site:

WCDMA

WCDMA

MHA

MHA

WCDMA antennas:

3 pcs

WCDMA MHAs:

6 pcs

Triplexers:

6 pcs

Feederlines:

6 pcs

GSM 900 / GSM 1800 / WCDMA Triplexer- 2

GSM 900 / GSM 1800 / WCDMA Triplexer- 1

Mast Head Amplifiers

• Triplexer supports MHA in one GSM 900 branch BTS • Additional MHAs to be equipped with direct DC feed

GSM 1800

WCDMA

BTS

BTS with Bias- Ts

194 Company Confidential

Upgrades to Current GSM Antennas Upgrade : space + polarization diversity

Current : space diversity

Space Space diversity diversity improves improves performance performance 0.5..1.0 0.5..1.0 dB dB compared compared to single radome. to single radome. The The gain gain of of 2.5 2.5 dB dB assumes assumes single single radome. radome. 1300 mm

Current : polarization diversity

150 mm

Antennas can be shared with GSM

Upgrade: 2 x polarization diversity within one radome Company Confidential

300 mm

195

Example: common feeders, separate antennas

TPX DPX

Triplexer Abis/Iub To/From BSC/RNC

DPX

• GSM 900/1800 BTS & WCDMA BTS • Triplexers – common feeders • Separate antennas – 900/1800 MHz dual-band – 2 GHz

Triplexer Iub

Power

Site Support System

GSM BTS

WCDMA

BTS

196 Company Confidential

Nokia Base Stations and Co-Siting Air-interface issues • WCDMA - WCDMA Co-Siting – This has been taken into account in 3GPP Air Interface Specifications – Nokia WCDMA base station products are compliant with 3GPP • WCDMA - GSM900 Co-Siting – This has been taken into account with Nokia's WCDMA and GSM900 base station design • WCDMA - GSM1800 Co-Siting – This is as with GSM900 – If GSM1800 Transmitter Frequency separation within same sector is more than 57 MHz( bottom channels) or 40 MHz (top channels), extra transmitter filtering (~10 dB) may be required in GSM1800 BTS • Note: 30 dB Minimum Coupling Loss (MCL) assumed between antennas

197 Company Confidential

Co-Siting with other manufacturers Air-interface issues • WCDMA Co-Siting with other manufacturers' equipment – theoretical worst case requires 50 dB extra isolation in GSM BTS – in practice this much will not be needed – Nokia can provide assistance with co-siting issues • Note: 30 dB Minimum Coupling Loss (MCL) assumed between antennas

198 Company Confidential

WCDMA - GSM Interference Outline • • • • •

Spurious emissions Nonlinear distortion Specifications and isolation requirements Interference mitigation methods Co-located sites

199 Company Confidential

WCDMA - GSM Interference Outline • Site and equipment sharing is an important issue to cut costs down and to guarantee proper function of the networks. • Common • base station mechanics • site support • transmission • antennas and feeders • site construction • network management • By proper site design (antenna installation etc.) interference coupling between systems can be reduced and unreasonable degradation of service due to co-sited installations avoided. • Co-siting preferred to avoid high path loss differences between own and neighbour systems. 200 Company Confidential

Spurious emissions • ITU-R definition of Spurious Emission (ITU-R: 329-7_ww7.doc): – Spurious Emission: Emission on a frequency or frequencies which are outside the necessary bandwidth and the level of which may be reduced without affecting the corresponding transmissions of information. Spurious emissions include harmonic emissions, parasitic emissions, intermodulation products and frequency conversion products, but exclude out-of-band emissions. • Normally the intermodulation distortion (IMD) is handled separately due to its importance. • Spurious signals can be coupled by – radiation – conduction – combination of radiation and conduction

201 Company Confidential

Nonlinear system • Nonlinear system transfer function can be expressed as a series expansion

x

System

y = a0 + a1x + a2x2 + a3x3 + ...

• In the case of one input frequency, vin = cos ω1t, output will consist of harmonics, mω1 – Fundamental (m = 1) frequency is the desired one. – If m > 1, there are higher order harmonics in output => harmonic distortion. – Can be generated both inside an offender or a victim system. • In the case of two input frequencies, vin = cos ω1t + cos ω2t , output will consist of harmonics mω1 + nω2, where n and m are positive or negative integers. – Intermodulation is a process generating an output signal containing frequency components not present in the input signal and it is called intermodulation distortion (IMD). – Most harmful are 3rd order (|m| + |n| = 3) products. – Can be generated both inside an offender or a victim system. 202 Company Confidential

Nonlinear components • Nonlinearities of active components like amplifiers under normal operation. • Nonlinearities of passive components – Antennas – Feeders – Connectors • Antenna mismatching – Reflected wave can cause IMD in the power amplifier. • Damaged feeders => mismatching • Loose connectors => mismatching, reflections and rectification.

203 Company Confidential

Active nonlinear distortion • Active nonlinear distortion is generated in nonlinearities of active components like amplifiers and modulators • The nonlinearity effect is especially strong in power amplifiers if they are driven to saturation. • Intermodulation levels of the amplifiers can be decreased by backing-off of them. • The amplitude of the 3rd order product increases 3 dB compared to the fundamental frequencies due to x3 term of it. • Active IMD generated inside an offender BTS can be removed by BTS TX filtering.

3rd order intercept point

Desired signal slope = 1

3rd order IMD slope = 3 204 Company Confidential

Passive nonlinear distortion • Passive nonlinear distortion is generated in nonlinearities of passive components like connectors, antennas and feeders. • Contact and material nonlinearities – Loose connectors – Oxidation of joints – Cracks in materials – Electron tunneling through layers – Nonlinear resistivity of materials – B/H nonlinear hysteresis • Levels normally lower than in active IMD. • Aging of the components increases IMD • Can NOT be filtered out in BTS TX.

I

V

B

H

205 Company Confidential

Harmonic distortion • Harmonic distortion can be a problem in the case of co-siting of GSM900 and WCDMA. • GSM900 DL frequencies are 935 - 960 MHz and second harmonics may fall into the WCDMA TDD band and into the lower end of the FDD band. 2nd harmonics fGSM = 950 - 960 MHz

GSM900 935 - 960 MHz

...

• 2nd harmonics can be filtered out at the output of GSM900 BTS.

WCDMA WCDMA FDD TDD 1920 - 1980

1900 1920 MHz

Company Confidential

206

IMD3 from GSM1800 DL to WCDMA UL • GSM1800 IM3 products are hitting into the WCDMA FDD UL RX band if • 1862.6 ≤ f2 ≤ 1879.8 MHz • 1805.2 ≤ f1 ≤ 1839.6 MHz

fIM3 = 2f2 - f1

f1

f2 X dBc fIM3

GSM1800 UL

GSM1800 DL

• For active elements IM products levels are higher than IM products produced by passive components • Typical IM3 suppression values for power amplifiers are -30 … -50 dBc depending on frequency spacing and offset • Typical values for passive elements are -100 … -160 dBc

WCDMA UL

WCDMA DL

1710 - 1785 MHz 1805 - 1880 MHz40 MHz1920 - 1980 MHz 2110 - 2170 MHz 207

Company Confidential

Nonlinear distortion conclusions • Second harmonics from the GSM900 system may fall into the WCDMA TDD band. • Intermodulation can be a problem if an operator has a splitted GSM1800 band or in multioperator systems. • The most harmful intermodulation products are 3rd order products which may fall into the WCDMA RX band: fIM3 = 2f1,2 — f2,1 • IM products can be avoided by proper frequency planning in GSM. • fIM3 is hitting into the WCDMA FDD RX band (1920 - 1980 MHz) if GSM1800 channels are from 512 to 684 (f2) and from 799 to 885 (f1). • Active intermodulation products can be filtered out in GSM1800 BTS TX – IM products generated inside a WCDMA receiver cannot be filtered out. • Passive IM products can not be filtered out in BTS TX if they are generated in feeder lines and connectors after the filtering unit of BTS. • Some aging problems may be avoided by installation, site administration and maintenance recommendations. 208 Company Confidential

RF Specifications • GSM 05.05-8.7.1, WCDMA TS 25.104-3.5.0 • Two main reasons to isolate GSM and WCDMA – Blocking – Sensitivity Transmitter GSM spurious GSM main UMTS spurious UMTS main

Frequency Level Parameter affected [MHz] [dBm] / [MHz] 1920 – 1980 UMTS BTS −96 / 0.1 (FDD UL) sensitivity -80 / 4.0 +40 / 0.2 UMTS BTS 1805 − Typical blocking 1880 GSM BTS 1710 − −98 / 0.1 sensitivity 1785 −95 / 0.2 2110 – 2170 +43 / 4.0 GSM BTS (FDD DL) Typical blocking

Required Required [dBm] / MHz isolation [dB] 28 < −108 / 4.0 (Noise floor) 55 < −15 / CW (Specifications) 15 < −110 / 0.2 (Typical) 0 43 (Specifications)

209 Company Confidential

Interference mitigation methods

• Means to achieve the required isolation – RF-methods • Tighter filtering of the GSM BTS TX signal • Proper frequency planning in GSM • Di- or triplexer in case of feeder and antenna sharing between different systems • By proper antenna selection and placing – Baseband methods • Interference cancellation receivers • If the interferer is known its effect can be removed easily – Combined RF and baseband methods

210 Company Confidential

Antenna isolation measurements • Measurements performed in an anechoic room in a GSM1800 band with a HP8753/D network analyzer. • According to the most common definition the far field assumption is valid if

df =

2D 2

λ

, and d f , D >> λ

where D is the largest dimension of an antenna, λ is wavelength and df is the distance from antenna. • The far field assumption is not valid => measurements needed. • For a typical GSM1800 antenna dimensions (D ≈ 1 m) df ≈ 13 m. • Let's assume coupling loss of 65 dB from the near field to the far field => – Extra 10 dB means therefore about 30 m distance by deploying a free space model from d0 = 10 m.

211 Company Confidential

Isolation measurements Antennas and configurations Antenna A B C D

Vert. Pol

Dual. Pol

d

d

Horizontal beamwidth 65º 90º 90º 90º

d

Gain 18 dBi 16 dBi 17.5 dBi 16 dBi

Polarisation Vertically linear Vertically linear Vertically linear +/- 45º dual pol.

Frequency band 1710 – 1880 MHz 1710 – 1880 MHz 1710 – 1880 MHz 1710 – 1880 MHz

120°

d

d

d I (90°)

II (120°)

III (180°)

IV (Horizontal)

V (Vertical)

1TSG-RAN

Working Group 4 (Radio) Meeting #8 TSGR4#8(99)631 Sophia Antipolis, France 26-29 October 1999 Company Confidential Source: Allgon

212

Antenna isolation measurements Setup I d

d

I (90°)

II d

120°

II (120°)

Antenna

d [mm] / Min

d [mm] / Max

isolation [dB]

isolation [dB]

A

250 / 50

850 / 63

B

250 / 46

975 / 59

C

250 / 54

950 / 62

D, Co-polar

200 / 46

1250 / 59

D, Cross-polar

200 / 49

1000 / 58

A

Same mast / 49

1050 / 66

B

Same mast / 38

1100 / 66

C

Same mast / 53

1150 / 68

D, Co-polar

Same mast / 38

1100 / 65

D, Cross-polar

Same mast / 43

1050 / 63 213

Company Confidential

Antenna isolation measurements Setup III d

III (180°)

IV

d

Antenna

d [mm] / Min

d [mm] / Max

isolation [dB]

isolation [dB]

A

Same mast / 52

750 / 71

B

Same mast / 49

1300 / 69

C

Same mast / 52

1150 / 76

D, Co-polar

Same mast / 38

1250 / 62

D, Cross-polar Same mast / 53

1250 / 62

A

250 / 37

6000 / 57

B

250 / 27

6000 / 52

C

250 / 34

6000 / 48

D, Co-polar

250 / 33

4250 / 53

D, Cross-polar 250 / 36

6000 / 57

IV (Horizontal) 214 Company Confidential

Antenna isolation measurements Setup V d

V (Vertical)

Antenna

d [mm] / Min d [mm] / Max isolation [dB]

isolation [dB]

A

2250 / 50

6000 / 70

B C D, Co-polar D, Cross-polar

2250 / 55 2250 / 61 1500 / 42 1500 / 44

5500 / 69 6000 / 66 6000 / 61 5500 / 65

215 Company Confidential

Antenna isolation measurements • Measurements performed in a more realistic environment by Nokia. • The used antennas are listed in the table below Band

Manufacturer

Model No

Horizontal Beamwidth

Polarisation

Vertical Beamwidth

Gain

Electrical Downtilt

UMTS GSM1800 GSM1800 GSM1800 GSM1800

Racal CSA CSA CSA CSA

UMTSXP/65/17.7/2 PCNV065-13-0B PCNV065-13-0B PCNV085-13-0B PCNA115-19-0B

65 deg. 65 deg. 65 deg. 85 deg. 115 deg.

X-polar X-polar X-polar X-polar Vertical

7 deg 7 deg 7 deg 7 deg 5 deg

17.7dB 18 dBi 18 dBi 16 dBi 17dBi

2 deg 0 deg 0 deg 0 deg 0 deg

• Horizontal, vertical and combined displacement configurations measured. • Rooftop, face and tower mounted measurements. • Both co- and cross-polar feed used.

216 Company Confidential

Antenna isolation measurements • Measured frequencies from 1710 to 1980 MHz and results collected from 1900, 1950 and 1980 MHz. • Measurement corresponds spurious emissions attenuation from the GSM1800 band into the WCDMA band.

output

Antenna A (fixed)

input

Network Analyser Figure 3. Equipment set up

Company Confidential

Antenna B

217

Antenna isolation measurements: Horizontal Antenna B UMTS

Antenna A (fixed)

Front View

horizontal separation distance

Side View

direction of radiation

1000mm

2000mm 400mm

650mm

Figure 5. Sketch of measurement configuration

Company Confidential

218

Antenna isolation measurements: Horizontal

GSM1800 65 deg to UMTS 65 deg Horizontal co-polar measurements 75.00

Isolation (dB)

70.00

1900MHz 1950MHz 1980MHz

65.00 60.00 55.00 50dB marker

50.00 45.00 40.00

00 0.

1.

00

2.

00

3.

00

4.

00

00 5.

6.

00

7.

00

8.

00

9.

00

1.

..

Distance (m) 219 Company Confidential

Antenna isolation measurements: Horizontal

GSM1800 85 deg to UMTS 65 deg Horizontal co-polar measurements

65.00

55.00 50dB marker

50.00 45.00 40.00

1900MHz 1950MHz 1980MHz

35.00

9. 00 10 .0 0

Distance (m)

8. 00

7. 00

6. 00

5. 00

4. 00

3. 00

2. 00

1. 00

30.00

0. 00

Isolation (dB)

60.00

220 Company Confidential

Antenna isolation measurements: Horizontal

GSM1800 115 deg to UMTS 65 deg Horizontal measurements 60.00

50dB marker

50.00

1900MHz 1950MHz 1980MHz

45.00 40.00 35.00

0

12

.0

0 .0

0

11

.0

10

9. 00

8. 00

7. 00

6. 00

5. 00

4. 00

3. 00

2. 00

1. 00

30.00 0. 00

Isolation (dB)

55.00

Distance (m) 221 Company Confidential

Antenna isolation measurements: Face Antenna A GSM1800

Front View

5m

1m

Antenna B UMTS

Side View direction of radiation

1000mm 2000mm

300mm

400mm

650mm

direction of radiation

Figure 9. Sketch of measurement configuration

Company Confidential

222

Antenna isolation measurements: Face Face mounting GSM1800 85 deg to UMTS 65 deg Co-polar 85.00 1900MHz

1950MHz

80.00

1980MHz

75.00

70.00 0.00

1.00

2.00

3.00

4.00

5.00

223 Company Confidential

Antenna isolation measurements: Vertical

Antenna B UMTS

Antenna A GSM1800 (fixed)

10m

Figure 11. Sketch of measurement configuration

Company Confidential

224

Antenna isolation measurements: Vertical

GSM1800 115 deg to UMTS 65 deg Noise Floor

85.00

Noise Floor

75.00

1900MHz 1950MHz 1980MHz

70.00 65.00 60.00 55.00

1. 50

1. 25

0 1. 0

5 0. 7

0. 50

0. 25

0

50.00

0. 0

Isolation (dB)

80.00

Distance (m) 225 Company Confidential

Antenna measurement conclusions • According to the measurements it's easy to find a configuration, which provides isolation of 30 - 60 dB. • Lowest isolation (27 dB) was measured in an anechoic room antennas horizontally displaced 0.25 m – with 6 m distance isolation was already about 50 - 55 dB. • Highest isolation values were measured with the face mounted antenna and the isolation was more than 70 dB. • In Allgon's measurements both antennas were for GSM1800 and in Nokia's measurements for GSM1800 and WCDMA. – There is also attenuation between GSM1800 and WCDMA due to frequency difference of them => isolation figures are higher for the spurious emissions.

226 Company Confidential

Isolation 800/900 - UMTS ‹

Horizontal Separation : XPol 900 65° _ XPol UMTS (824-960) (1710-2170)

227 Company Confidential

Isolation 800/900 - UMTS ‹

Horizontal Separation : XPol 900 90° _ XPol UMTS (824-960) (1710-2170)

228 Company Confidential

Isolation 800/900 - UMTS ‹

Vertical Separation : XPol 900 65° _ XPol UMTS (824-960) (1710-2170)

229 Company Confidential

Isolation 800/900 - UMTS ‹

Vertical Separation : XPol 900 90° _ XPol UMTS (824-960) (1710-2170)

230 Company Confidential

Isolation 800/900 - UMTS ‹

Separation by 120° : XPol 900 65° _ XPol UMTS (824-960) (1710-2170)

231 Company Confidential

Isolation 800/900 - UMTS ‹

Separation by 120° : XPol 900 90° _ XPol UMTS (824-960) (1710-2170)

232 Company Confidential

Isolation 1800/1900 - UMTS ‹

Horizontal Separation : XPol 1800 65° _ XPol UMTS (1710-1990) (1710-2170)

233 Company Confidential

Isolation 1800/1900 - UMTS ‹

Horizontal Separation : XPol 1800 90° _ XPol UMTS (1710-1880) (1710-2170)

234 Company Confidential

Isolation 1800/1900 - UMTS ‹

Vertical Separation : XPol 1800 65° _ XPol UMTS (1710-1990) (1710-2170)

235 Company Confidential

Isolation 1800/1900 - UMTS ‹

Vertical Separation : XPol 1800 90° _ XPol UMTS (1710-1880) (1710-2170)

236 Company Confidential

Isolation 1800/1900 - UMTS ‹

Separation by 120° : XPol 1800 65° _ XPol UMTS (1710-1990) (1710-2170)

237 Company Confidential

Isolation 1800/1900 - UMTS ‹

Separation by 120° : XPol 1800 90° _ XPol UMTS (1710-1880) (1710-2170)

238 Company Confidential

Isolation Dualband GSM 900/1800 - UMTS ‹

Horizontal Separation : XXPol 900/1800 65°/65° _ XPol UMTS (870-960/1710-1880) (1710-2170)

239 Company Confidential

Isolation Dualband GSM 900/1800 - UMTS ‹

Vertical Separation : XXPol 900/1800 65°/65° _ XPol UMTS (870-960/1710-1880) (1710-2170)

240 Company Confidential

Isolation UMTS - UMTS ‹

Horizontal Separation : XPol UMTS 65° _ XPol UMTS (1710-2170) (1710-2170)

241 Company Confidential

Isolation UMTS - UMTS ‹

Vertical Separation : XPol UMTS 65° _ XPol UMTS (1710-2170) (1710-2170)

242 Company Confidential

Isolation UMTS - UMTS ‹

Separation by 120°: XPol UMTS 65° _ XPol UMTS (1710-2170) (1710-2170)

243 Company Confidential

Part XI WCDMA Optimization

244 Company Confidential

Network Optimization Process Objective: To optimize the outdoor part of the 3G network, this done cluster wise, as they are being integrated. The main elements for this process are: 1.Pre-optimisationsurvey 2.Network check 3.Initial drive test, baseline 4.Pre-Launch optimization •Cluster tuning until break-out point is reached •Ready for network acceptance & reporting

245 Company Confidential

Pre Launch Optimization-Overview

246 Company Confidential

Pre Launch Optimization-Process

247 Company Confidential

Optimization-Overview

248 Company Confidential

Optimization-Overview Block A

249 Company Confidential

Optimization-Overview Block A

250 Company Confidential

Optimization-Overview Block B

251 Company Confidential

Optimization-Overview Block C

252 Company Confidential

Optimisation - required performance • Examples of performance metrics – Area of service availability or coverage performance – Average FER, BLER – Access failures including paging and SMS – MOC/MOT Call Setup Failures – Dropped call performance – Handover percentage (Soft/Hard) – Ec/Io&RSCP performance • UMTS Bearer Service Attributes – Maximum/Average bitrate (kbps) – Residual bit error ratio – Transfer Delay – Guaranteed bitrate (kbps) 253 Company Confidential

Key Performance Indicators, KPI • KPIs are a set of selected indicators which are used for measuring the current network performance and trends. • KPIs highlight the key factors of network monitoring and warn in time of potential problems. KPIs are also used to prioritise the corrective actions. • KPIs can be defined for circuit switched and packet switched traffic separately and be measured by field measurement systems and Nokia NetActTM network management system. • An example set of KPIs – RRC Setup Complete Ratio – RAB Setup Complete Ratio – RAB Active Complete Ratio – Call Setup Success Ratio – Call Drop Rate – Softer/Soft Handover Fail Ratio

254 Company Confidential

WCDMA RAN Optimisation WCDMA RAN

Network Management • Nokia NetActTM for 3G • Field Tool Server

configuration KPIs, counters

me as

Configuration

ur e me nt

KPIs, measurements

s

air-interface

RAN Optimisation • pre-defined procedures • semi / full automated

Start

WindowAdd WindrowDrop Change 1 stepsize Change 1 stepsize

No

CompThreshold Change 1 stepsize

DropTimer Change 1 stepsize

NMS: Collect network performance data

Evaluate KPI 'HO Overhead'. OK ?

Field Tool

Yes

Evaluate all network KPIs. OK ?

No

Go to relevant optimisation flow-chart

Yes

End

255 Company Confidential

WCDMA Field Tool • Measurement data with Phase 1

location and timestamp • File & remote IP based interface

• Measurement data with location and timestamp

Phase 2 Post Processing Tool

Data Logging Tool

• connection to NMS Field Tool Server

• Map map data • Network network configuration configuration information

Company Confidential

256

Part XII Radio Resource Management

257 Company Confidential

Radio Resource Management

258 Company Confidential

Radio Resource Management

259 Company Confidential

Radio Resource Management

260 Company Confidential

Radio Resource Management

261 Company Confidential

RRM Control Processes

262 Company Confidential

WCDMA Radio Resource Management: Logical Model LC

PS RM

• AC Admission Control • LC Load Control

AC Network based functions

• PS Packet Scheduler • RM Resource Manager • PC Power Control

PC

• HC HO Control

HC Connection based functions

263 Company Confidential

RRM control processes • Admission control: –Performs the admission control for new bearers to enter/leave the network. –Predicts the interference caused by the bearer and checks whether there is room for it. –Power allocation • Packet Scheduler –Scheduling packets to the radio interface (UL/DL) • Load Control: –Takes care of radio network stability –Gathers interference information and produces a load vector • Resource manager –Manages the physical resources of RAN and maintains the code allocation 264 Company Confidential

RRM control processes • Power Control –Closed loop PC compares the measured SIR with SIR-target and accordingly transmits an up/down PC command at 0.667 ms interval –Open loop PC estimates the needed power based on pathloss + interference measurements (RACH). –Outer loop PC sets the SIR target for the fast closed loop PC • Handover Control –Soft (intra-frequency) handovers: softer between cells within one BS, intra-RNC soft, inter-RNC soft –Inter-frequency (hard) handovers: Intra-BS, Intra-RNC, Inter-RNC (-MSC) –Inter-RAT handovers: WCDMA GSM 265 Company Confidential

Power Control Power Control loops in WCDMA MS

BTS

RNC

Open Loop Power Control (Initial Access) Closed Loop Power Control Outer Loop Power Control

266 Company Confidential

Power Control Loops • Effective power control is essential in WCDMA due to frequency re-use factor of one (in ideal case) • Closed loop e.q. Fast power control – Makes Eb/No requirements lower – Equalizes received powers at BTS in uplink (avoids near-far effect) – Introduces interference peaks in the transmission • Open loop power control for initial power setting of the UE • Outer PC loop at a slower rate, across the Iub interface in uplink – At a much slower rate, across the Iub interface in uplink – Adjusts the SIR target to achieve a target BLER – Also similar outer loop power control in MS – There is also similar outer loop power control in UE 267 Company Confidential

Power Control & Diversity • At low UE speed, power control compensates the fading : fairly constant receive power and Tx power with high variations • With diversity the variations in Tx power is less • At UE speed >100kmph fast power control cannot follow the fast fading, therefore diversity helps keep receive power level more or less constant • In the UL Tx affects adjacent cell interference and Rx power affects interference within the cell.

268 Company Confidential

Admission Control & Packet Scheduler • AC handles new incoming traffic to the RAN by –estimating the total load caused by adding a new RAB in uplink and downlink –and decides whether or not this can be admitted. • AC also sets : –initial DL transmission power for the channel –the power control range as well as many other parameters, e.g. Transport Format Set. • PS handles all the NRT data connections. PS is determining the time a packet is sent and which bit rate is used. 269 Company Confidential

Admission Control & Packet Scheduler • The key function of AC and PS is to maximize capacity (throughput) by estimating the load and to fill the system up to maximum loading while still ensuring the required quality of service for RT traffic. • In uplink, the basic measured quantity indicating load is the total received power of a BS, PrxTotal • In downlink, the basic measured quantity indicating load is the total transmitted power of a BS, PtxTotal

270 Company Confidential

Admission Control Uplink admission control • In uplink the total received wideband interference power measured indicates the traffic load of the radio resources . • The fundamental criteria of evaluation is based on

Itotal_old + ∆I < Ithreshold • Ithreshold indicates the traffic load of the radio resources • In uplink, the total received power is the function of the maximum interference received in the wideband spectrum. power

Ithreshol

max planned power

d

∆I =?

Itotal_old

max planned load

Company Confidential

load

271

Admission Control Uplink admission control UL interference power

Prx_target_BS Marginal load area

Prx_offset

Prx_target TRHO_threshold

planned uplink interference power Planned load area

Load

Prx_target defines the optimal operating point of the cell interference power, up to which the AC of the RNC can operate.

272

Company Confidential

Admission Control Downlink admission control DL transmission power

Ptx_target_BS Ptx_target

Marginal load area

Ptx_offset

TRHO_threshold

Planned load area

planned Downlink interference: carrier transmission power

Load

Downlink power increase estimation is done for non-controllable load just like UL power increase. 273 Company Confidential

Packet Scheduler • Packet scheduler is a general feature, which takes care of scheduling radio resources for NRT radio access bearers for both uplink and downlink. • The packet access procedure in WCDMA should keep the interference caused to other users as small as possible. • Packet access is implemented for both dedicated (DCH) and common control transport channels (RACH/FACH). • There are three scenarios for WCDMA packet access: •

infrequent transmission of short packets,

•

frequent transmission of short packets (RACH/FACH)

• transmission of long packets (DCH) • Packet scheduler makes the decision of the used channel type for downlink direction. For uplink direction the decision of the used channel type is made by UE 274 Company Confidential

Packet Scheduler Capacity Division • The proportion between RT and NRT traffic varies all the time • It is characteristics for RT traffic that the load caused by it cannot be controlled in efficient way. • The available capacity, which is not used for non-controllable load, can be used for NRT radio access bearers on best effort basis. load

planned target load free capacity, which can be allocated for controllable load on best effort basis

non-controllable load

time Company Confidential

275

Packet Scheduler Load Decrease Example

276 Company Confidential

Packet Scheduling Principle

277 Company Confidential

Load Control Capacity • The traffic can be divided into two groups – Real Time (RT) – Non-Real Time (NRT) • THUS some portion of capacity must be reserved for the RT traffic for mobility purposes all the time. The proportion between RT and NRT traffic varies all the time. Overload area Overload Margin Power

Load Target

Estimated capacity for NRT traffic. Measured load caused by noncontrollable load

Time

278 Company Confidential

Load Control Definition of Non-controllable traffic • Since it is not enough to divide the load to RT and NRT one must take into account the interference coming from surrounding cells. Traffic is divided into controllable and non-controllable traffic. Non-controllable traffic =

RT users + other-cell users + noise + other NRT users which operate minimum bit rate

Controllable traffic =

NRT users

279 Company Confidential

Logical description of load control • The purpose of load control is to optimize the capacity of a cell and prevent overload situation. • Load control consists of Admission Control (AC) and Packet Scheduler (PS) algorithms, and Load Control (LC) which updates the load status of the cell based on resource measurements and estimations provided by AC and PS. Load change info Load status

LC

NRT load

AC

PS

280 Company Confidential

Handover Control

281 Company Confidential

Handover Control - WCDMA Handovers • Supported WCDMA handovers for PS and CS services : • Soft handover – MS simultaneously connected to many cells – Mobile Evaluated HandOver (MEHO) – Intrafrequency handover • Hard handover – Intrafrequency hard handover • Arises when interRNC SHO is impossible • Decision procedure is the same as SHO; MEHO and RNC controlled • Causes temporary disconnection of the user – Inter-frequency handover • Can be intraBS hard handover, intraRNC hard handover, interRNC hard handover • Network Evaluated HandOver (NEHO) • Decision algorithm located in RNC – Inter-RAT handover 282 • Handovers between GSM and WCDMA Company Confidential

Softer Handover • • Sector/Antenna RAKE combining (MRC)

• • •

• • RNC

Handover between cells within a BS softer handover is handled by BS internally softer handover probability about 5 - 15 % no extra transmissions across Iub basically same RAKE MRC processing as for multipath/antenna diversity (BS / MS). More RAKE fingers needed. provides additional diversity gain softer handover does create additional interference and needs BS PA resources 283

Company Confidential

Soft handover • • • •

Handover between cells from different BS's Soft handover probability about 20 - 50 % Required to avoid near/far effects Extra transmission across Iub, more channel cards are needed RNC CN

• • •

•

frame selection / duplication

fo bility in a i l e r frame

DL/MS: Maximal ratio combining fra m e UL/RNC: Frame selection combining re lia Soft handover does create additional bi lit yi interference in downlink and needs BS nf o power amplifier resources DL Power drifting in soft HO BSs a problem due to independent errors in uplink commands Company Confidential

Except for the TPC symbol exactly the same information (symbols) sent over air. Differential delay in order of fraction of symbol duration

284

Handover Control – IntraFrequency Handovers

285 Company Confidential

Handover Control – IntraFrequency Handovers

286 Company Confidential

Handover Control – IntraFrequency Handovers

287 Company Confidential

Handover Control IntraFrequency Handovers Measurements

288 Company Confidential

Handover Control IntraFrequency Measurement Reporting Events

289 Company Confidential

Handover Control IntraFrequency Measurement Reporting Events

290 Company Confidential

Handover Control IntraFrequency Measurement Reporting Events

291 Company Confidential

Handover Control IntraFrequency Measurement Reporting Events

292 Company Confidential

Differences between Handovers

293 Company Confidential

Benefits from Inter-System handover

294 Company Confidential

Load and coverage reasons handover

295 Company Confidential

Service Control

296 Company Confidential

Resource Manager • The main function of RM is to allocate logical radio resources of BS according to the channel request by the RRC layer for each radio connection • The RM is located in the RNC and it works in close co-operation with the AC and the PS • The actual input for resource allocation comes from the AC /PS and RM informs the PS about the resource situation • The RM is able to switch codes and code types for different reasons such as soft handover and defragmentation of code tree. • Manages the BS logical resources – BS reports the available logical HW resources • Maintains the code tree, – Allocates the DL channelization codes, UL scrambling code, UL channelization code type • Allocates UTRAN Registration Area(URA) specific Radio Network Temporary Identifier(RNTI) allocated for each connection and reallocated 297 when updating URA Company Confidential

Resource Manager Spreading • Spreading = channelization and scrambling operations (producing the signal at the chip rate, i.e. spreads the signal to the wideband) • Downlink: Scrambling code separates the cells and channelization code separates connection • Uplink: Scrambling code separates the MS's, channelization code separates the DPDCHs in case of multicode • The length of the channelization code is the spreading factor • All physical channels are spread with channelization codes, Cm(n) and subsequently by the scrambling code, CFSCR • The code order, m and the code number, n designates each and every channellization code in the layered orthogonal code sequences. widespread data

user data chanellization scrambling code code Company Confidential

298