Technology WCDMA Introduction

7/30/2019 Technology WCDMA Introduction

1/57

WCDMA/HSPA network setting

overview


2/57

2

Summary

WCDMA/HSPA/HSPA+ key concept

Cell planning difference between 2G/3G

Link budget difference between 2G/3G

optimization


3/57

3

WCDMA/HSPA/HSPA+

WCDMA Max traffic ch code = 512 (total) 40 (CCH) = 472

HSPA Fixed SF=16

Hybrid ARQ

No fast power control, no soft HO

Adaptive modulation/coding (QPSK or 16QAM)

PS scheduler depending on Ec/Nt, QoS

HSPA+ DC-HSDPA

MIMO support for QPSK/16QAM

64QAM for some MS categories


4/57

4

Cell planning difference 2G/3G

GSM Planning is focused on coverage Performance depend on C/I

Capacity fixed on available 200k channel

WCDMA Cell breathing coverage decreases as network loading

increases Higher noise rise (UL)

Lower Tx power per user (DL)

Capacity is interference limited

Planning is focused on Ec/Io, soft handover %, PSCallocation, neighbor list,..


5/57

5

Link budget difference 2G/3G

GSM typically have higher Tx power in UL/DLcompared to WCDMA E.g., GSM has 43dBm(DL)/33dBm(UL)

E.g., WCDMA has 33.6dBm (CPICH-DL)/24dBm(UL)

Frequency X2 freq path loss increase by 6dB E.g., GSM900WCDMA at 2.1GHz, pathloss+7.2dB (typ 8~9dB)

Coverage limitation in DL for GSM, UL for WCDMA

Rx sensitivity difference for 12.2kbps voice Effective BW = 200kHz for GSM, 5MHz/PG=15.6kHz for WCDMA

C/I = 9dB+3dB(margin)=12dB for GSM, 7dB (due to WB, fast PC,SHO gain) for WCDMA

WCDMA has better rx sens by 200/15.6 + (12-7) = 16dB


6/57

6

Link budget result example

Coverage advantage of GSM900 overWCDMA2100

8~9dB (x2 freq) + 9dB (power) 16dB (rx sens)

= 1~2dB

If same size antenna is used forGSM900/WCDMA2100

Typically 2.1GHz antenna has 3.5dB higher gain

Compared with 12.2k voice GSM

12.2k voice WCDMA has 1.5~2.5dB gain UL 64k WCDMA has same coverage

UL 128k WCDMA has 1.2~2.2dB loss


7/577

Optimization Excessive propagation is a problem in WCDMA

Pilot pollution need more tilt as traffic increases

Soft/softer HO Avoid excessive HO regions (used up traffic CE)

Shared antenna system more tilt (e.g., 2~4deg) than GSM

Duplexer loss reduce coverage

Co-located GSM/3G sites

GSM/WCDMA, WCDMA/WCDMA neighbor Load balancing Interference management

PSC planning (code and index) Critical for neighbor list and high sites etc


8/578

UMTS Radio Planning

CDMA systems show a certain relationbetween capacity and coverage, so thenetwork planning process itself depends notonly on propagation but also on cell load.

Thus, the results of network planning aresensitive to the capacity requirements. UMTSforces radio network planners to abandon thecoverage first, capacity later approach.

Furthermore, for a given design load, due tothe large difference in services bit rates andQoS requirements, UMTS networks exhibitseveral cell ranges possibilities.


9/579

Cell Range

GSM UMTS

speech/data SF=256SF=32SF=8

coverage (EM power >threshold) coverage, load, services, interference

Cell range highly depends on


10/5710

Codes

All W-CDMA users occupy the same frequency atthe same time, thus frequency and time are notused as discriminators.

W-CDMA operates by using CODES to discriminatebetween users. The receiver will hear all thetransmitter signals mixed together, but by using thecorrect code sequence, it can decipher the requiredtransmission channel and the rest is background

noise.

Spreading sequences are actually unique streamsof 1 and -1 which compose the code associatedwith a user. Therefore, users are discriminatedthanks to spreading codes.


11/5711

Channelization Codes

Channelization Codes : Users data ismodulated by a channelization code. Theorthogonality properties of OVSF enable the

UE to recover its bits without beinginterfered by other users. This is true only ifthe system is synchronous, which is thecase in downlink, but not in uplink. Thus, the

OVSF codes are not used to separate usersin uplink and therefore different users canuse the same code. But they can be used todistinguish the different physical channels of

one user.


12/5712

Scrambling codes

The scrambling operation is used for base stationand mobile station identification. In downlink, thesame scrambling code can be used on differentchannels in a cell, but different scrambling codesare used in different cells. In uplink, scrambling

codes are used to differentiate users. Scrambling codes reduce the interference between

neighboring cells in downlink since samechannelization codes are used.

It is important to maintain good cross-correlationproperties between the different scrambling codesin order not to decode an interferer.

Similar to the reuse of frequency in GSM,scrambling codes are reused.


13/5713

Scrambling codes

The number of SC used in uplink 2^24 ----NoUplink SC planning

The number of SC used in DL is 512-----Dowlink SC planning based on neighboringrelations.


14/5714

Codes


15/57

HSDPA


16/57

16

Radio Resource Allocation

Shared Channel

Dedicated Channel

Dedicated Channel

Dedicated Channel


17/57

17

DCH/DSCH

DCH transmitted on DPCHFixed SF (SF determines the channelisation code).Power controlled, support for SHO, highest rate 2 Mbps.

DSCH transmitted on PDSCHVariable SF.

Always DCH associated.DSCH is shared by several users (single or multi-code

transmission).Power controlled (DPCCH), no support for SHO.


18/57

18

User Throughput Management

Rate

Adaptation

Power

Control

Data Power

Unused Power

100% Power

100%

Data

Unused

Same Throughput


19/57

19

HSDPA Channel Operation

HS-SCCH

Downlink Transfer Infor

(UEid, OVSF,...)

HS-PDSCH

Data Transfer

(PS I/B)

DPCH

Upper Layer Signaling

2ms

UE #1

UE #2

UE #3

UE #4

UE #5

OVSF

codes

HS-DPCCH

Feedback Information

(ACK/NACK, CQI)

DPCH

Upper Layer Signal

HS-DPCCH

Feedback Informati

(ACK/NACK, CQI)


20/57

20

OVSF Code Tree Reservation

SF4

SF8

SF16SF32

SF64

SF128

SF256

cmCH

. . .

HS-PDSCH

HS-SCCH

. . .

. . .

. . .

HSDPA + R4

SF4

SF8

SF16

SF32

SF64

SF128

HS-PDSCH

HS-SCCH

HSDPA


21/57

21

Scheduler Behavior

FAIR

FAIR

RR

RR CQI

CQI PROPORTIONAL FAIR

PROPORTIONAL FAIR


22/57

22

AMC Principles

QPSK

QPSK

QPSK

16QAM

16QAM

-20 -15 -10 -5 0 50

100

200

300

400

500

600

700

800

Ior/Ioc (dB)

Throughput

(kbps)

AMC IllustrationUE Category Reported CQI

CodingRate ModulationScheme Number ofOVSF Codes

AM

C

2m

s

Selected TFRC


23/57

23

23

Channel coding Allowed combinations form TFRC (Transport Format and

Resource Combination).

Given sufficiently good channel conditions, a single usermay simultanously reveive 15 parallel multi-codes.


24/57

24

UE Categories

QPSK mandatory for HSDPA capable UE

16-QAM optional

HS-DSCH

Category

HS-PDSCH Max

Number

Inter-TTI Min

Interval

Modulation Max Peak

Rate

Category 1 5 3 QPSK & 16-

QAM

1.2 Mbps


QAM

1.2 Mbps


QAM

1.8 Mbps


QAM

1.8 Mbps

Category 5 5 1 QPSK & 16-QAM

3.6 Mbps


QAM

3.6 Mbps


QAM

7.3 Mbps


QAM

7.3 Mbps


QAM

10.2 Mbps


QAM

14.4 Mbps

Category 11 5 2 QPSK only 0.9 Mbps

Category 12 5 1 QPSK only 1.8 Mbps


25/57

25

UE Capabilities and Max Bit Rates

-10 -8 -6 -4 -2 0 2 4 6 8 1010

15

20

25

C/I (dB)

softCQI

Soft CQI vs C/I - Pedestrian_a 1 RX

Category 6 UE CQI Mapping Table

CQI

Value

HS-PDSCH

Number

RLC

Throughput

Modulatio

n

0 out of range

1 1 0 kbps QPSK

2 1 0 kbps QPSK

3 1 0 kbps QPSK

4 1 0 kbps QPSK

5 1 144 kbps QPSK

6 1 144 kbps QPSK

7 2 144 kbps QPSK

8 2 288 kbps QPSK

9 2 288 kbps QPSK

10 3 432 kbps QPSK

11 3 576 kbps QPSK

12 3 720 kbps QPSK

13 4 864 kbps QPSK

14 4 1008 kbps QPSK

15 5 1296 kbps QPSK

16 5 1440 kbps 16-QAM

... ... ... ...

29 5 3024 kbps 16-QAM

30 5 3024 kbps 16-QAM

Target BLER 10%


26/57

HSUPA


27/57

27

Release 99: Dedicated channels in Downlink and Uplink

HSDPA (Release 5)

Shared downlink channel (TDMA), implementing

new techniques Uplink remains unchanged

HSUPA (Release 6)

Downlink identical to HSDPA

Implementing the same techniques (more or less)in the Uplink

WCDMA HSDPA HSUPA

DL DPCH 1

UL DCH 1

DL DPCH 2

UL DCH 2

HS-DSCH

UL A-DCH 1

HS-DSCH

UL A-DCH 2

HS-DSCH

UL E-DCH 1

HS-DSCH

UL E-DCH 2


28/57

28

Same principles as HSDPA HSUPA is the uplink counterpart ofHSDPA

Thanks to link adaptation methods (shorter TTI,

HARQ, fast scheduling), it achieves: Higher peak data rates (up to 5.6 Mbps) and cell

capacity

Reduced latency

Fast HARQ (Hybrid Automated Repeat Request) The RBS can rapidly request retransmission of

erroneously received data, which implies increasedrobustness

Higher error probability is supported

Faster TTI (Transmission time interval): 2ms insteadof 10ms

Allows reduction of latency and increased cellthroughput

Tighter resource control, allowing additional capacity

Fast Scheduling The system rapidly adapts to interference variations

and re-allocates resources between UEs

Controlled by Node B instead of RNC

2 ms


29/57

29

but UL and DL are fundamentally

different

Shared channel in HSDPA,Dedicated channels in HSUPA

Shared resource: Power and code forHSDPA

Interference headroom forHSUPA Scheduling applies to: User data rate in HSDPA

Interference level in HSUPA

Power control Soft handover

Higher order modulations

Shared Resource

Soft Handover


30/57

30

Resource sharing: HSDPA vs. HSUPA

Common channels

HSDPA

Release 99

Downlink

Power,codespace

UplinkInterference

Thermal Noise

Interference headroom for HSUPA

Release 99 in-cell interference

Inter-cell interference

Cell A

Cell B Cell CCell B

Cell C

Cell A

RoT


31/57

31

Load Control

The Rise-over-Thermal (RoT) is monitored by

the serving Node B

Absolute grant can increase or decrease the E-DPDCHpower, i.e. the data rate

Relative grant can only hold or decrease the E-DPDCHpower, i.e. the data rate, in order to limit the amount of inter-cell interference


32/57

32

New channels Downlink

E-AGCH (Absolute Grants Channel for E-DCH scheduling)

E-HICH (HARQ ACK/NACK IndicatorChannel) E-RGCH (Relative Grants Channel for E-DCH scheduling)

Uplink

E-DPDCH (E-DCH user data)

E-DPCCH (E-DCH control information: E-TFCI, happy bit,

RSN)


33/57

33

Planet Modules for WCDMA/HSPA+

Traffic map generator

Subscriber Manager

WCDMA Analysis Module (RCSP, Pilotcoverage, service coverage, handoverstate.)

Scrambling code planning


34/57

34

Traffic MapA traffic map is used to determine areas that

Currently carry high voice traffic Currently carry high data traffic

A Traffic map is used as an input for WCDMAanalysis, it will give the number of subscribers

to include in analysis.Typically, we will haveone traffic map per service.

The input of the traffic Map are :

Population data or subscriber data

Nework data (obtained from the switch)


35/57

35

Subscriber Manager

The subscriber Manager module is designedto define the types of subscribers, theirequipements, services and associatedquality of service.

Si l ti


36/57

36

Simulation

WCDMA Network analysis: Suitable for intialNetwork coverage planning and CPICHanalysis (Coverage and pollution). Thisalgorithm is an UMTS link budget based on

load assumptions (Noise rise)

Monte Carlo : Provides comprehensive

analysis of the network including Power limits,codes limits, Throuphout, channel elementlimits.


37/57

37

Monte Carlo Algorithm Planets Monte Carlo Simulation tool is based

on

creating semi-random patterns of users basedon traffic map distribution,bearers, andequipment, then repeating this process for aspecified number of times. Each repetition ofthe pattern generation process is a run.

Repeating the runs helps you determine howthe network performs under a variety of

conditions with a variety of subscribers andequipment.

Statistically, each individual run is of littlevalue. However, over many Monte Carlo runs,

the average result provides a realisticre resentation of the network.


38/57

MONTE CARLO Simulation

M t C l Si l ti


39/57

39

Monte Carlo Simulations

A Monte carto Simulation is based on manyruns. On Each run, the subscribers are spreadon different locations.

A big number of runs allow to cover all the

possible positions of subscribers. The final result is obtained using averages on

the individual results

The algorithm will stop when the convergence

factor is reached

M t C l


40/57

40

Monte Carlo runA monte Carlo run will spread the subcribers

over a geographical area according to the

density of the traffic map. The number ofmobiles to be spread is computed from thetraffic map

The mobiles that belong to services withhighest priority will be placed and connected tothe network first

During a run, the algorithm will try to serve oneby one the number of simultaneous mobilesuntil a constraint is broken (Noise Rise Maxreached, Maximal Power of Node B reached,CE, OVSF Codes..)


41/57

41

Monte Carlo Run : No. of Subscribers Spread

(Step 1)

Qty of Subscribers to spread comes from Traffic map, and Erlangper Subscriber value.

Its is computed for Both Circuit or Packet switched traffic.

CS: E.g. 1000 voice subscribers in the traffic map, for 25 mErlangper subscriber, returns 1000 x 0.025 = 25 subscribers spread inthe analysis

PS: For Packet Users, we need a representation of the amount oftime that a connection is active, in much the same way as the'Erlangs per subscriber' is for Circuit traffic. So we calculate avalue of 'packet data Erlangs per subscriber' based on theSession type (which basically provides the proportions ofactivity/no-activity in a session), the Service (which gives theamount of data transferred per user, plus overheads), and thebearers used (which provide the amount of time that it takes totransfer that data). The combination of these items gives us theactivity representation for a single user.


42/57

42

Monte Carlo run : Placing

subscribers

(Step 2)

The simulation places the subscribers atrandom locations using the traffic map

densities, and determines the subscriber typesfrom the definitions in the Subscriber Manager.

Monte Carlo run : Power Control


43/57

43

Monte Carlo run : Power Control

UMTS is based on Power control un Uplink andDownlink Directions

UL: The BS will indicate to each mobile therequired power to be used in order to meetEb/N0 requirements on UL. This power willdepend on the position of the mobile and the

used service, Limitation of UL interferences

DL : The BS will transmit on the trafic channeldedicated for Mobile Mi, the power required toobtain a DL Eb/N0 equal to the

Pnode_B=PCPICH+PSCH/CCH+ PTch(Mi)

Limitation of DL interferences

Monte Carlo run : UL Coverage


44/57

44

Monte Carlo run : UL Coverage

(Step 3)

Generates uplink analyses : This uses the random

subscriber pattern to determine the number ofsubscribers that can be served, while taking intoaccount the impact of each served subscriber on thenetwork.

A subcriver can be served on Uplink if:

The power required to communicate with the BS is

below the value of the maximal power of the Mobile. Admission control : The current noise rise(Generated by all served mobiles) of the BS is belowthe Noise rise Max

Noise Rise= 10.log{1/(1-L)}

Monte Carlo run : DL Coverage


45/57

45

Monte Carlo run : DL Coverage

(Step 4)

A mobile is covered on Downlink if these radioconditions are verified:

Pilot Coverage (Ec/I0 > Ec/I0 Threshold) Service Coverage(Eb/N0 at least equal to Eb/N0

Threshold)

Additional conditions are considered to connect

Mobiles on DL The Power of the Node-B is below the Max

Number of OVSF codes

Number of CE

Throughout of the Site

Generates downlink analyses : To do this, the simulation

uses the best serving sector information determined in

the uplink analysis


46/57

46

Last Run

On the last run of the simulation, the simulationtool also generates two additional types ofdata:

Operating pointsThese are the results of

the simulation divided by sector, carrier, andsubscriber type. Planet averages these anduses them to create analysis layers.

Discrete subscriber informationPlanet

compiles snapshots of eachsubscribersstatus on each run of the simulation


47/57

47

Network analysis

It is a link budget that provide simplifiedanalysis for uplink and Downlink loading.

Detailed Subscriber information is not required.

Nominal subscriber information is used instead

This algorithm will not provide informationabout the use of power, OVSF codes andchannel elements since traffic map is not used.

Can be used for Initial Network planning and if

the network is not loaded.


48/57

48

HSUPA in Planet 5.2

As part of the WCDMA tool, HSUPA is beingimplemented in Planet 5.2

On top of the existing Rel99, HSDPA and

Rel99&HSDPA carrier types, two new carriertypes have been created:

HSPA

Rel99&HSPA

HSPA = HSDPA (Downlink) + HSUPA (Uplink)


49/57

49

Network Settings - Carriers


50/57

50

Network Settings - FRC

Network Settings FRC


51/57

51

Network Settings - FRC FRC: Fixed Reference Channel

A FRC represents an E-DCH channel configuration

They have been used for testing purposes

FRC

TTI

Length(ms)

Number of Codes

Coding

rate

Max

Data

Rate(kbps)

HSUPA

UECategorySF2 SF4 SF16

1 2 0 2 0 0.71 1353 2

2 2 2 0 0 0.71 2706 4

3 2 2 2 0 0.71 4059 6

4 10 0 1 0 0.53 508 1

5 10 0 2 0 0.51 980 2,3

6 10 2 0 0 0.51 1960 4,5

7 10 0 0 1 0.29 69 1


52/57

52

Downlink channels

Although HSUPA is anuplink technology, newdownlink channels arenecessary

E-AGCH

E-HICH

E-RGCH

They are combined

underHSUPA ControlChannels and theirpower is specified inthe sector settings,along with the othercommon channels


53/57

53

Uplink Noise Rise

DPCH Noise Rise: Noise due to Release 99and HSDPA subscribers

Total Uplink Noise Rise: Total noise, includingHSUPA traffic

Uplink

Interference

Thermal Noise

DPCH Noise Rise

E-DPCH Noise Rise

DPCH Noise Rise (dB)

Total Uplink Noise Rise (dB)


54/57

54

Uplink Noise RiseAll uplink layers

are based onthe Total uplinknoise rise

What is the

DPCH NoiseRise for?


55/57

55

E-DCH Layers FRC Coverage probability

Only for selected data rates Based on slow fading standard deviation (clutter types GUI)and required Ec/No for the FRC (Network settings)

Max Achievable data rate

This is the data rate of the best FRC that achieves the celledge coverage probability (Services GUI: typically 85%)

Average data rate

This takes all selected FRCs into account and calculates theaverage data rate based on each FRCs coverage probability


56/57

56

E-DCH LayersE-DCH Coverage

for FRC1

E-DCH Max

Achievable Data

Rate

E-DCH Coverage

for FRC1

E-DCH Max

Achievable Data

Rate

E-DCH Average

Data Rate

E-DCH Average

Data Rate

Monte-Carlo simulation


57/57

Monte-Carlo simulation

HSUPA is supported by the Monte-Carlo tool

As a result, HSPA carriers will spread HSDPA subscribers

Rel99&HSPA carriers will spread Release 99subscribers and HSDPA subscribers and HSUPAsubscribers

Noise Rise The noise rise output of the Monte Carlo simulation

includes the DPCH Noise Rise and HSUPA traffic

The Total Noise Rise defined in the sector settings(including HSUPA traffic) will be used by the layers

Technology WCDMA Introduction

Documents

Transcript of Technology WCDMA Introduction