01%2E 8 Years of CDMA Experience v5

NORTEL NETWORKS CONFIDENTIAL Version 3.1

Leveraging Nortel’s 8 Year CDMA Experience For UMTS Product and Engineering

Chang-Gang Zhang ( 张长钢 )

Sept. 2003

NTCDMA - 2NORTEL NETWORKS CONFIDENTIAL

Nortel UMTS Key Differentiators

• UMTS (W-CDMA) is fundamentally a CDMA technology

• Nortel is the only leading UMTS (W-CDMA) vendor with industry leading CDMA capacity and performance

• Nortel is the only leading UMTS (W-CDMA) vendor with 8 year solid experience in CDMA Product R&D

• Nortel is the only leading UMTS (W-CDMA) vendor with 8 year extensive experience in network Engineering


UMTS -- A CDMA TechnologySame Technical Characteristics Higher Bandwidth

开环，闭环 ( 内环 , 外环 ) ，速率 800Hz

闭环 ( 内环，外环 ) ，速率 1500Hz

功率控制

可变速率 (based on voice activity)

自适应多速率 (based on RF condition)

语音编码

软切换，频间切换，与IS-95 间的切换

软切换，频间切换，与 GSM 间的切换

切换

QPSK( 前向 ) ， BPSK( 后向 )

QPSK( 前向 ) ， BPSK( 后向 )

调制方式20ms 等10ms幀长

同步需 GPS异步 ( 不需 GPS), 同步

基站同步方式1.2288Mcps3.84Mcps码片速率FDDFDD双工方式

单载波宽带直接序列扩频 cdma

单载波宽带直接序列扩频 cdma

接入方式1.25MHz5MHz信道间隔

cdma2000UMTS





• Nortel is the only leading UMTS (W-CDMA) vendor with solid experience in CDMA Product R&D

• Nortel is the only leading UMTS (W-CDMA) vendor with extensive experience in network Engineering


北电网络的北电网络的 3G3G 移动通信地位移动通信地位

WCDMAWCDMA

•16 16 个网络个网络•88 个国家个国家•15% 15% 市场份额市场份额

CDMA2000CDMA2000

•6565 个运营商个运营商•17 17 个国家个国家•224%4% 市场份额市场份额

北电网络是唯一在所有主要北电网络是唯一在所有主要 3G3G 无线技术领域无线技术领域都有投资和研发的厂商都有投资和研发的厂商


Nortel Industry Leadership in CDMA Capacity

• Nortel has deployed CDMA (IS-95/CDMA2000) networks for 65 operators in 17 countries

• Nortel has the highest capacity in 2nd Generation CDMA technology– 13k Vocoder - 13 Users/sector/carrier, 6.61 Erlangs @ 1% GOS– EVRC - 24 Users/sector/carrier, 15.30 Erlangs @ 1% GOS

• Nortel 1XRTT Product has the highest capacity– 35 Users/Sector/carrier, 24.6 Erlangs @ 1% GOS

• Benefit Nortel product development and deployment to deliver high standard UMTS network from day one


KPI Improvement for CDMA 2G

0

0.5

1

1.5

2

2.5

3

19990803

19990805

19990807

19990809

20030804

20030806

20030808

AF %

CD %

KPI Improvement for CDMA 3G Voice

00.20.40.60.8

11.21.41.61.8

2

20020806

20020807

20020808

20020809

20020810

20030810

20030806

20030807

20030808

20030809

AF %

CD %

Nortel Industry Leadership in CDMA Performance (commercial networks)

• CDMA2000 achieves 4 years IS-95 improvement in one year• Demonstrate experiences gained in product, RF design and network optimization• Similar experiences apply to UMTS Early maturity and high performance means CSAT, revenue, lower cost

CDMA IS-95 CDMA2000


CDMA 1xRTT Market Data Performance

• Customer Field Throughput measurement in loaded network closes to theory with Nortel product

– Large cell cluster drive, mixed with commercial voice traffic– Finite burst, SCH SHO enabled (2), under mobility (40km/h)– QOSPI = 76.8kbps, physical layer throughput recorded– Results correlated reasonably well with empirical models, developed as part of trial,

based on available fwd power

Max Data Throughput in 1xRTT Marketing Trial Footprint

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 10 20 30 40 50 60 70 80 90

Data Speed (kbps)

Pro

bab

ility

of

Ach

ievi

ng

Sp

eed

March 2002 (Actual)

March 2002 (Theory)

c

Mkt Trial (Actual)

Mkt Trial (Theory)





• Nortel is the only leading UMTS (W-CDMA) vendor with solid experience in CDMA Product R&D

• Nortel is the only leading UMTS (W-CDMA) vendor with extensive experience in network Engineering


How CDMA Was Leveraged in UMTS Access portfolio

Reuse of CDMA proven hardware and software

• Univity iBTS hardware– iBTS architecture base on CDMA Metrocell BTS. 2

years ahead of most competitors.

– UMTS RF is 80% component to component compatible with CDMA

– ASICs have been field proven avoiding any risk of hardware replacement

– 45W MCPA 8 years of CDMA

expertise built inside!• Univity RNC software

– IntelligentRRM (iRM) taken from CDMA, ensures high quality/capacity UMTS networks. Strategy is much different from GSM network.

– Field Proven Basic CDMA functions. Power control, PA power management, soft & softer handoff algorithms taken from CDMA ensure quality and capacity.


How CDMA Was Leveraged in UMTS Univity iBTS

• Easier & cheaper PA upgrade costs– Easy expansion to second carrier without re-

engineering– 55% CAPEX savings for PA upgrade with 3

times less PAs than industry’s standard during network densification

TRM

OTSRTRM

TRM

Ca p

a cit

y

38%38%

100%100%

180%180%

246%246%

356%356%

PA

PA

PA

PA

PA

5Mhz 10Mhz 15Mhz

PA

TxDiversity

Ca p

a cit

y

100%100%

180%180%

246%246%

356%356%

5Mhz 10Mhz 15Mhz

Coupling

Coupling

Coupling

PA

PA

PA

Coupling

PA

PA

PA

Coupling

Coupling

Coupling

PA

PA

PA

Coupling

Coupling

No No SolutionSolution

TxDiversity

PA

PA

PA

Coupling

Coupling

Coupling

Normal

Nortel Competitor

CDMA experience minimize Capex and Opex


• Higher coverage– Nortel Networks Univity iBTS 45W PA offers 15%

additional coverage.– Asymmetrical Design offer additional 25%

coverage. – Boomer Cell

• Up to 90W per Carrier

• Higher coverage/capacity for higher data rates

• Higher Capacity– One Cabinet Solution for 15MHz + Tx Diversity

(20W per carrier per sector).– OTSR for initial network launch to minimize

network cost for best performance.

CDMA experience minimize Capex and Opex

How CDMA Was Leveraged in UMTS Univity iBTS


20001990s late2002/3?2001

UM

TS

2000

Airt

el 1

2/20

00

Can

nes

2/20

01

Mob

ilKom

/ A

irtel

Lau

nch

Q4/

2002

Nortel Networks

First 3GPP iBTS

Nortel NetworksTDMA MCPA

Complete multi carrier design with

continuing enhancements

The competition copies our strategy …

Vendor NMono/bi carrier

Vendor EMCPA

Vendor N announces

MCPA

Vendor E announces

MCPA

Mono/bi-carrier design

Competitors follow

How CDMA Was Leveraged in UMTSMCPA in iBTS


• Successful handovers– Nortel Networks is the first 3G vendor to

supply full 3G mobility (soft/softer handover in packet and voice) meaning:

• Less dropped calls

• Less waste of call processing resources

– First 3G vendor to perform 3G-to-2G handover calls on end to end 3GPP network

CDMA experience ensures QoS, coverage & maximizes profitability

Soft, Softer &hard HO

• Nortel’s Market Leading QoS – User Segmentations (Gold, Silver and Bronze)

• Cost Reduction

• Subscriber Satisfaction

• Maximized Revenues

Copyright © 1996 Northern Telecom

Brown UserCollege Student Executive Video Conference, e-

mail, net-meeting, e-commerse…

Cop

yrig

ht ©

199

6 N

orth

ern

Tel

ecom

Willing to pay much more if his need is satisfied.

Need high bandwidth, reliable, secured and lossless 3G services

Gold User

Need 3G services without too much demand on QoS

How CDMA Was Leveraged in UMTS Univity RNC


Boomer CellBoomer Cell

•增强前向链路 - 90W 功放•增强反向链路 - 采用高性能塔顶低噪声放大器

，改善反向链路

•解决时延问题 - 采用增强型信道单元模块和软件

- 扩大接入信道搜索窗- 话务信道搜索窗可调 --

径向切换

10 倍于普通基站的覆盖范围10 倍于普通基站的覆盖范围

How CDMA Was Leveraged in UMTS Boomer Cell


• Fast power control is critical• CDMA DL power control is enhanced from

50Hz in IS-95 to 800Hz in CDMA-2000• Nortel DL power control sync algorithm is key

differentiatorFast Forward Power Control (1xRTT) vs Slow Forward Power Control (IS95)

-0.1

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0.5

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1.3

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Time

Forw

ard

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atts

)

BTS Forward Power - IS95 Voice

BTS Forward Power - 1xRTT Voice

Down Link Power Control (CDMA)

Log (distance)

Path loss

Slow fading

Fast fadingSig

nal

lev

el (

dB

)


• UMTS has implemented faster DL power control– UMTS power control speed at 1500Hz

– Inner loop power update on per slot basis

– Outer loop SIR update on per frame or TTI basis

• Power Control sync is more important and challenge to implement

Down Link Power Control (UMTS)

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80

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Average of DL SIR Average of DL TPC NORM Average of BestEcNo

Average of RL 1 Average of RL 2 Average of BLR DTCH

6 per. Mov. Avg. (Average of DL TPC NORM) 6 per. Mov. Avg. (Average of DL SIR) 4 per. Mov. Avg. (Average of BestEcNo)


• Nortel developed and implemented MCTA algorithm for multi carrier resource pooling

• Support up to 9 carrier allocation

• Support carrier allocation across different frequency band

• Manage resources for both voice and data

• Increase trunking efficiency for high capacity

MCTA for Multi Carrier Resource Pooling (CDMA)PCS Band

F1

F2

F9

F8

F7

F3

①

②③

⑤

⑥

⑦F8

F7

F9

④

F7

Cellular Band

2 Carriers 3 Carriers13k 12% 16%

8k/EVRC 9% 13%13k 10% 13%

8k/EVRC 8% 10%

MCTA Erlang Gain

Mobility

FWA


iMCTA for UMTS Traffic Management

F1

F2

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py

rig

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GSM

• GSM could be the last resort if all WCDMA carriers are overloaded

• Similar algorithm applied to UMTS• Support up to 4 frequencies with load threshold

and priority• Select highest priority first, in case of same

priority, select the lowest loaded


RRM Balance Resources and QoS (CDMA)

• Aggressive RRM in handling the resource allocation for voice and data is critical to achieve high

– Capacity– Service availability– Quality

CEM

CEM

CEM

CCM (0)

GPSAM

TRM

CEM

TRM

TRM

Data Power(% of max.

power)

Voice Power(% of max. power)

Max. Power line

100%

100%

Td=40%

Tv=80%60%

20%Voice and Data both

guaranteedVoice is guaranteed at least

60%, data at least 20%


With good RRM algorithm and optimized parameters,With good RRM algorithm and optimized parameters,customers will get desired bandwidth as they need it customers will get desired bandwidth as they need it

CSAT, RevenueCSAT, RevenueNortel is delivering this performance !!!Nortel is delivering this performance !!!

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%BW Request

BW Available

RRM Balance Resources and QoS (CDMA)

• RRM algorithm and RRM parameter optimization delivers QoS

• Customer field measured bandwidth availability vs request demonstrate good performance

NTCDMA - 22NORTEL NETWORKS CONFIDENTIALManaged QoS, Higher Capacity, Differentiation

Intelligent RRM for Managed QoS (UMTS)


iRRM for Managed QoS (UMTS)Call Admission Control

• Intelligent CAC in RRM by considering resources, cell loading, link quality, user QoS, etc. for call assignment


iRRM for Managed QoS (UMTS)Scheduling

• Scheduling in RRM performs RB reconfiguration when link becomes weak for better resources utilization


Copyright © 1996 Northern Telecom

Brown User

严先生

College Student

赵先生

Executive

Video Conference, e-mail, net-meeting, e-commerse…

Entertainment

Web Browsing, On line chat and Music/Picture download…

Cop

yrig

ht ©

199

6 N

orth

ern

Tel

ecom

Only afford existing GSM monthly bill

for 3G services.

Willing to pay much more if his need is

satisfied.

Need high bandwidth, reliable, secured and lossless wireless services

Gold User

Need basic 3G services without too much demand on QoS

Maximize UMTS network profitability.With 8 years CDMA experience, Nortel has the best knowledge

to implement UMTS QoS without impacting CDMA network stability.

iRRM for Managed QoS (UMTS)User Segmentations (Gold, Silver and Bronze)


• Multi Pilot Hard Handover greatly improves hard handover robustness– Multi carrier overlay creates

carrier boundary– Hard handover takes place at

carrier boundary– Single target hard handover

experiences higher failure rate– Multi pilots provide multiple

handover targets– Mobile enters soft handover

immediately after hard handover

– Increase hard handover success rate by 5%

Advanced Hard Handover Algorithm (CDMA) Nortel Multi Pilot Hard Handover

RTD threshold boundary

F1F 1

F 2 In-traffic Hard Handover

MPHHO functionality

Transition Cell

Know how to implement blind handover effectively in UMTS without major impact on capacity !!


UMTS Hard Handover Compressed Mode vs Blind Mode

• Compress Mode– Transmission gaps provided for UE to retune and search inter

frequency handover candidates

– UE transmits at x2 Rate immediately before and after gap using secondary spreading codes (non orthogonal) Other options include reduced interleaving on primary code.

– Interleaved sequences required to search GSM RSSI and BSIC

• Blind Mode– Handover is triggered based on static pre-configured information

– No measurement is performed

– Target cell is pre-selected based on engineering experience


• Capacity decreases in larger clusters• Tolerable if UMTS deployed initially in small clusters with

low traffic expectations• “Blind Hard Handover” to alternate carrier should be

considered

RSSI CM Measurement Trigger (dBm) - -90 -85 GSM Border Handoff Thresh (dBm) -95 -95 -95 % Users in Compressed Mode 0 5.1 11.8 % PA Power on Secondary Codes 0 17.5 33 Carried Voice Traffic (Erlangs) 42 32 23 % Erlang Capacity 100.0% 74.4% 53.5%

RSSI trigger level has a huge impact on the RSSI trigger level has a huge impact on the

applicability of Compressed Mode, it is not the applicability of Compressed Mode, it is not the best compromise to guarantee handoff reliabilitybest compromise to guarantee handoff reliability

Based on simulations

UMTS Hard Handover Compressed Mode Impact





• Nortel is the only leading UMTS (W-CDMA) vendor with 8 years solid experience in CDMA Product R&D

• Nortel is the only leading UMTS (W-CDMA) vendor with 8 years extensive experience in network Engineering


Network Engineering ExperienceCDMA RF Optimization

• Unlike FDMA/TDMA systems, parameters are less used to influence system

Everything is co-channel therefore, if signal is present, cannot choose

whether to use it or not.

Parameter settings are mainly dictated by the network through analysis

of trace data and traffic.

Seeking optimal operation point in multi dimensional space

Main aspects to control are handoff thresholds, power allocations,

power control, access parameters, power management

Good RF Design plus subsequent antenna changes are the main

impacting factors that influence Network Performance.


Create Dominant Server CPICH Ec/IoUMTS RF Engineering


Pilot Pollution ControlUMTS RF Engineering

Network coverage control optimization Network coverage control optimization comparison before and aftercomparison before and after


Down Link Power Management (CDMA)

New OH Power0 %

20 %

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80 %

60 %

40 %

Old

OH

Pow

er

Tra

ffic

Pow

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Power Per User

Increased traffic capacity

• CDMA capacity is down link power limited in capacity deployment

• Optimizing power allocation to the various channels is crucial

• Nortel has optimized early CDMA overhead power of about 40% down to less than 20%

• Power per traffic channel has also greatly reduced

NP P P P

P SPUCallBlock Pilot Page Sync

Link

=- + +( )

*

Improved Power utilization equals increased Traffic Capacity


Down Link Power Management (UMTS)UMTS RF Engineering

• Nortel UMTS DL power management function has taken advantage of CDMA experience and offers customer great flexibility and control for optimization

• Our initial parameter setting provides good start

• Nortel experience will help customers to reach optimum balance between capacity and performance

CDMA experience helps UMTS engineering for increased Traffic Capacity


• Soft handover gain is manifested in a lower average mobile transmit power

• Soft handover is an important tool to extend cell coverage

• Soft handover in transition zones must be carefully planned

20 15 10 5 0 5 10 15 200

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Single Server

Two Servers (50% correlation)


SHO Gain

@ 90% Rel.

Required link margin for two servers @ 90%

reliability

Required link margin for one server @ 90%

reliability

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Single Server



SHO Gain

@ 90% Rel.

Required link margin for two servers @ 90%

reliability

Required link margin for one server @ 90%

reliability

0.9

Soft HO extends coverage, reduce Soft HO extends coverage, reduce cell countcell count

Re

liab

ility

Soft Handoff Gain Benefits


Soft Handoff Control (CDMA)

• Soft handoff enhances link robust but cost resources

• Soft handoff optimization before/after achieves better tradeoff

• Nortel Soft handoff control algorithm helps save radio resources and gain up to 27% capacity from field measurement


• Based on CDMA experience Nortel implemented relative threshold based active set management in UMTS

• Rich experience in soft handover control

Soft Handover Control (UMTS)UMTS RF Engineering

Best measured Cell

CPICH Ec/No

(dB)

-20

0

Add threshold

Area where monitored cell are valid candidates to be in the next active set

Best measured Cell

CPICH Ec/N0

(dB)

-20

0

Drop threshold

Area where current active set cells are no longer valid candidates to be in the active set


Soft Handover Control (UMTS)UMTS RF Engineering

• Optimization reduces average SHO links before/after


TCP

IP

PPP

App

RLP

MUX

BSCBTS PDSN

R-P

MTClient

HDLC

RS232 RS232

IS2000IS2000 BCN

T1

ACN

BCN

RS422

ACN

RLP

MUX

Enet

10BT

IP

L2TP

UDP

L2

L1

IP

L2TP

UDP

IP

PPP

HDLC

IP

TCP

App

IP

L1

L2

L1

L2

Server

Pi

Engineering CDMA Data NetworkMultiple Protocol Layers and Network Nodes Involved

• Lower layer optimization same as voice– Interference control

– Power control

– Handoff control


Increasing RTO value may significantly increase TCP throughput

Single burst

Re-sent segmentsfrom previous burst

Engineering CDMA Data Network TCP Parameters Optimization


• If number of NAKs to recover a missing RLP frame to 6

• There are several possibilities: {1,2,3} or {2,2,2} or {4,1,1}, etc.

• For each setting there is a trade-off between RLP frame delay and residual RLP frame error

0

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0% 20% 40% 60% 80% 100%

FER

No

rma

lize

d T

hro

ug

hp

ut

{1,2,3}

{1,1,4}

{3,2,1}

{1,5,0}

Engineering CDMA Data Network RLP Parameters Optimization


DCRQ

RLPQ

FwdBuffHigh

FwdBuffLow

BufferThreshold_R4

BufferThreshold_R3

BufferThreshold_R2BufferThreshold_R1

BufferThreshold_Release

Data rate

Trash

MaxSecondsToBufferCall DCR Q Buffer Size

PDSN

FLOW Control

Engineering CDMA Data Network PCU Buffer, RLP Buffer Threshold Optimization

• Balance delay, RF resources and throughput

Nortel is Experienced in optimizing performance ofData Network


IP

SRNC

SGSN GGSNUE

BTS

RLC

PDCP

TCP/UDP

Application

W-CDMA

RF

W-CDMA

RF

Iub L1

ATM

AAL2

Frame Protocol

Iub L1

ATM

Frame Protocol

MAC

RLC

PDCP

Iu PS L1

ATM

AAL5

IP

UDP

GTP-U

Iu PS UP

Iu PS L1

ATM

AAL5

UDP

GTP-U

Iu PS UP

UDP

GTP-U

L1

L2

UDP

GTP-U

L1

L2

IP

Uu Iub Iu PS Gn

TCP/UDP

Access Network Core Network

IP IPIP

MAC

AAL2

Similar UMTS Protocol LayersBeneficial from CDMA data experience

Application


Engineering UMTS Data Network Understand TCP Principles

• TCP is designed for high reliable transmission medium with assumption that data segment losses are due to network congestion

• TCP over radio demonstrates very different behaviors• Bandwidth oscillation can largely impact TCP performance


Engineering UMTS Data Network TCP/IP Parameters Optimization

CDMA data optimization experience leads to the discovery of UMTS optimal MSS value, i.e. 1460 bytes

• MSS, i.e. MTU controls a TCP segmentation or packet size

• For smaller MSS the overhead of TCP/IP headers (40 bytes) becomes more important and wastes more bandwidth

• Larger MSS causes unnecessary segmentation and longer delay


Engineering UMTS Data Network TCP Parameters Optimization

• TCP fast retransmit and recover mechanism is used to avoid waiting for the RTO to detect packet loss and to avoid TCP falling into slow-start


Engineering UMTS Data Network TCP RLC Interaction

• High TCP anticipation may overflow RLC buffer and cause TCP packets lost

• The RTO timer will expire and TCP without receiving ACKS will consider this as network congestion

• TCP will go into slow-start and retransmit the oldest packet not ACKed


Engineering UMTS Data Network RLC Parameters Optimization

• RLC throughput has dependency on the TimerStatusProhibit, high value means less status report request, and better throughput


Engineering UMTS Data Network RLC Parameters Optimization

• RLC throughput is sensitive to how often to poll the receiver

• Too often wastes bandwidth but detects packet loss early

• Less frequently saves bandwidth but detects packet loss too late

• Need to identify a balance


Test UE interfaced to:- Agilent Viper- Qualcomm QXDM

OAM

RFO Analysis Engine

Mobile logs RNC Call Trace Logs

Manual Datafill modificationsUsing Nortel OCAN

IU Protocol Analyzer (Optional)

Site Configuration & Nortel SpecificDatafill

Nortel UMTS Optimization Tool • Big contributor to achieve high capacity & performances

Based on Similar CDMA tool for UMTS optimization !!


Summary

Any technology/network take time and money to reach

optimum operation –> speed to achieve is critical !!

Nortel has accumulated 8+ years CDMA experiences Great asset absorbed in our UMTS product design and development Know-how in tweaking key performance parameters, design proprietary

algorithms, develop optimization tools

Best trade off among performance, capacity & resource utilization

High performance and lower maintenance

Low added equipment investment and opex

Nortel has the ability and strength to design, build and optimize UMTS network better and faster than anyone else; the performances of the CDMA network built by Nortel speaks for itself !!

01%2E 8 Years of CDMA Experience v5

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Transcript of 01%2E 8 Years of CDMA Experience v5