A Study of Non Real Time Radio Bearer
Packet Data Performance in UMTS
Radio Access Network
Seema Gyanwali
Supervisor: Professor Sven Gustav Häggman
Instructor: Janos Gyori
12.10.04
Contents
• Introduction
• Goals
• Background
• Measurement Introduction
• Measurement Method
• Results
• Conclusions
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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.
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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
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Background
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Network Elements
Uu
Node B
Iu
USIM
RNC
MSC/VLR
GMSC
PLMN, PSTN,
ISDN
Node B
Cu
Iub
Iur
HLR
Node B
ME
RNC
Node B
UE
SGSN
GGSN
UTRAN
CN
Internet
External Networks
Thesis work analysis in the Uu interface
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UMTS Qos Traffic Class
• Conversational class
• Streaming class
• Interactive class
• Background class
Traffic Class
Applications
Delay
Jitter
Conversational
(Real time)
Voice, one to one
video
Stringent
Stringent
Low
Losses
Constrained Constrained
Streaming (Real
time)
Broadcast audio video
Loose
Yes
Interactive (Non Web, database,
real time)
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Yes
games
Yes
Background (Non
real time)
Emails, file transfer
7
Guaranteed
Bit-rate
Yes
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UMTS Qos Architecture
UMTS
TE
MT
UTRAN/
GERAN
CN lu
edge
node
TE
CN
Gatew ay
End-to-End Services
TE/MT
Bearer
Services
Radio Access Bearer Services
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External
Bearer
Services
UMTS Bearer Service
Radio Bearer
Services
lu Bearer
services
Physical
Radio
Services
Physical
Bearer
Services
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CN Bearer
Services
BB Services
Seema Gyanwa
Measurement Area and Route
Overview of the test network
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Logging Tools
Test UE
RNC
RNC
TOM
FTP Server
Iu-PS
Iub
Node B
3G3G-SGSN
3G3G-SGSN
-SGSN
SGSN
GGSN
GGSN
FW
3G Nethawk
Analyzer
• 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
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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
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Measurement Results
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Throughput and RSCP for 384 kbps
RSCP: received power on one code measured on the primary CommonPilot
Channel
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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.
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Throughput and Downlink Radio Link Power
for
384 kbps
DL Radio Link Power
450000
45
400000
40
350000
35
300000
30
250000
25
200000
20
150000
15
100000
10
50000
5
0
0
1
101
201
301
401
501
601
701
801
DL Radio Link Power dBm
Throughput bps
Throughput
901
No. of Samples
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Throughput and RSCP for 128 kbps
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Throughput and EcNo for 128 kbps
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Throughput and Downlink Radio Link Power
for
128 kbps
DL Radio Link Pow er
160000
40
140000
35
120000
30
100000
25
80000
20
60000
15
40000
10
20000
5
0
0
1
101
201
301
401
501
601
701
801
DL Radio Link Power
dBm
Throughput bps
Throughput
901
No. of Samples
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Throughput and RSCP for 64 kbps
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Throughput and EcNo for 64 kbps
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Throughput and Downlink Radio Link Power
for
64 kbps
Throughput
80000
40
70000
35
60000
30
50000
25
40000
20
30000
15
20000
10
10000
5
0
0
101 201 301 401 501 601 701 801 901 1001
1
DL Radio Link Power
dBm
Throughput bps
DL Radio Link Pow er
No. of Samples
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Downlink Power for Different Radio Bearer
Services
64 kbps RB
128 kbps RB
384 kbps RB
Max power for 384 kbps
service
DL Radio Link Power dBm
45
Max power for 128 kbps
service
40
35
30
Max power for 64 kbps
service
25
20
15
652
621
590
559
528
497
466
435
404
373
342
311
280
249
218
187
156
125
94
63
32
1
10
No. of Samples
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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
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ref.Bit
rateref
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Average Throughput for Different Bearer
Services
Average Throughput
400
350
Bits per sec
300
250
200
365kbps
150
100
50
0
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121kbps
58kbps
384 kbps RB
128 kbps RB
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64 kbps RB
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Coverage area for different Radio Bearer
Services
RB in kbps
384 kbps RB
128 kbps RB
64 kbps RB
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RSCP in dBm
EcNo in dB
-102
-104
-105
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-9
-10
-11
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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
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