A Study of Non Real Time Radio Bearer Packet Data Performance in UMTS Radio Access Network

A Study of Non Real Time Radio Bearer

Packet Data Performance in UMTSRadio Access Network

Seema Gyanwali

Supervisor: Professor Sven Gustav Häggman

Instructor: Janos Gyori

12.10.04

2 Master’s thesis seminar presentation 12.10.2004 Seema Gyanwali

Contents

• Introduction

• Goals

• Background

• Measurement Introduction

• Measurement Method

• Results

• Conclusions


Introduction• Knowledge of Packet data transmission in the radio interface of UMTS and

factors involved in its transmission is not widely investigated and documented.

• Packet data performance is a broad concept which can be investigated from different perspectives for different purposes.

• This thesis studies the radio network parameters’ performance in WCDMA network for visualizing and optimizing packet data transmission.

• This work will help in the following aspect: • Validation of network design

• Validation of Planning assumptions such as – cell range– maximum acceptable load

• Dimensioning – Iub capacity, – Node B capacity

• Performance Optimisation• Radio coverage optimization• Analysis of radio link power and network tuning• Tuning of advanced features e.g. load and service tuning• Find out some statistics and the trends for reference purposes

• This work was done in Nokia Networks, Espoo.


Goals of the Thesis Work

The goal of the thesis is to:

• Conduct a drive test measurement in WCDMA test network

• Collect the performance data from the drive test

• Perform statistical analysis on the collected data to verify the packet data performance in different radio conditions

• Evaluate the throughput and maximum radio link power for different bearer services

• Analyse the coverage area for different bearer services

Scope:

• Scope of the work is limited to radio interface of WCDMA network only, it is not a study for end to end performance


Background


Network Elements

CN

MSC/VLR

SGSNRNC

Node B

Node B

RNC

Node B

Node B

UTRAN

Iu

IubIur

UE

USIM

Cu

Uu

ME

GMSC

GGSN

HLR

PLMN, PSTN,ISDN

Internet

External Networks

Thesis work analysis in the Uu interface


UMTS Qos Traffic Class• Conversational class

• Streaming class

• Interactive class

• Background class

Traffic Class Applications Delay Jitter Low Losses

Guaranteed Bit-rate

Conversational (Real time)

Voice, one to one video

Stringent Stringent Yes

Streaming (Real time) Broadcast audio video

Constrained Constrained Yes

Interactive (Non real time)

Web, database, games

Loose Yes

Background (Non real time) Emails, file transfer

Yes


UMTS Qos Architecture

PhysicalRadio

Services

PhysicalBearer Services

BB Serviceslu Bearerservices

Radio BearerServices

Radio Access Bearer Services CN Bearer Services

TE/MTBearer

ServicesUMTS Bearer Service

ExternalBearer

Services

End-to-End Services

TE CNGateway

CN luedgenode

UTRAN/GERAN

MT TE

UMTS

PhysicalRadio

Services

PhysicalBearer Services

BB Serviceslu Bearerservices

Radio BearerServices

Radio Access Bearer Services CN Bearer Services

TE/MTBearer

ServicesUMTS Bearer Service

ExternalBearer

Services

End-to-End Services

TE CNGateway

CN luedgenode

UTRAN/GERAN

MT TE

UMTS


Measurement Area and Route Overview of the test network


Logging Tools

• Nokia 3G test mobile

• TOM• A portable engineering tool, which is installed in the laptop to

measure and monitor the air interface of WCDMA wireless network

• Nethawk Analyzer• Real time monitoring tool to measure the Iub interfac

3G-SGSN

Test UE

TOM

RNC GGSN

Iu-PS

FW

Node B

Iub FTP Server

RNC GGSNGGSN FW3G-SGSN

3G-SGSN3G-SGSN

3G NethawkAnalyzer

3G-SGSN

Test UE

TOM

RNC GGSNGGSN

Iu-PS

FW

Node B

Iub FTP Server

RNC GGSNGGSN FW3G-SGSN

3G-SGSN3G-SGSN

3G NethawkAnalyzer


Measurement Method• A packet data call was established

• FTP download of a large file (100 Mb) was performed

• The call was maintained while driving from good coverage area to bad coverage area

• Measurements were repeated for different radio bearers (384 kbps, 128kbps, 64kbps services)

• Parameter:• MaxBitRateDLPSNRT

• Analyzing Tools:• Actix Analyzer• Excelsheet


Measurement Results


Throughput and RSCP for 384 kbps

RSCP: received power on one code measured on the primary CommonPilotChannel


Throughput and EcNo for 384 kbps

EcNo: Received energy per chip divided by the power density in the band.It gives the quality of the common pilot channel signal.


Throughput and Downlink Radio Link Power for384 kbps

0

50000

100000

150000

200000

250000

300000

350000

400000

450000

1 101 201 301 401 501 601 701 801 901

No. of Samples

Th

rou

gh

pu

t b

ps

0

5

10

15

20

25

30

35

40

45

DL

Rad

io L

ink P

ow

er

dB

m

Throughput DL Radio Link Power







0

20000

40000

60000

80000

100000

120000

140000

160000

1 101 201 301 401 501 601 701 801 901

No. of Samples

Th

rou

gh

pu

t b

ps

0

5

10

15

20

25

30

35

40

DL

Rad

io L

ink

Po

wer

d

Bm

Throughput DL Radio Link Pow er







0

10000

20000

30000

40000

50000

60000

70000

80000

1 101 201 301 401 501 601 701 801 901 1001

No. of Samples

Th

rou

gh

pu

t b

ps

0

5

10

15

20

25

30

35

40

DL

Rad

io L

ink

Po

wer

d

Bm

DL Radio Link Pow er Throughput


Downlink Power for Different Radio Bearer Services

10

15

20

25

30

35

40

451

32

63

94

12

5

15

6

18

7

21

8

24

9

28

0

31

1

34

2

37

3

40

4

43

5

46

6

49

7

52

8

55

9

59

0

62

1

65

2

No. of Samples

DL

Ra

dio

Lin

k P

ow

er

dB

m64 kbps RB 128 kbps RB 384 kbps RB

Max power for 64 kbpsservice




Downlink Power for Different Radio Bearer Services

For Non Real Time Traffic

Ptx_max_rl = min{Ptx_CPICH-CPICHtorefRABoffset + SF_adjustment, Ptxtotalmax-PTxDPCHmax}

SF_adjustment = Eb/No . Bit rate

Eb/No ref.Bit rateref


Average Throughput for Different Bearer Services

365kbps

121kbps

58kbps0

50

100

150

200

250

300

350

400

Bits

per

sec

Average Throughput

384 kbps R B 128 kbps R B 64 kbps R B

365kbps

121kbps

58kbps0

50

100

150

200

250

300

350

400

Bits

per

sec

Average Throughput

384 kbps R B 128 kbps R B 64 kbps R B


Coverage area for different Radio Bearer Services

RB in kbps RSCP in dBm EcNo in dB384 kbps RB -102 -9128 kbps RB -104 -1064 kbps RB -105 -11


Conclusion

Packet Data performance in different radio condition is verified. And the conclusion is:

1. The max bit rate for different bearer services cannot be achieved in the whole range of the cell

2. The average throughput value for each service profile is obtained which is below the nominal value due to the TCP features

3. In poor coverage area the RSCP and EcNo decreases and at a certain point the throughput starts to degrade because the DL radio link power reaches the maximum and it becomes difficult to maintain the quality

4. The RSCP and EcNo value, when the throughput starts to collapse for each service profile, is found out which is quite optimistic due to the fact that there were no other load in the cell and in the neighboring cell

5. Different bearer service has different coverage area

6. The maximum downlink radio link power is different for each bearer services and the power reaches the maximum at different points

Documents

A Study of Non Real Time Radio Bearer Packet Data Performance in UMTS Radio Access Network