18 optimization of umts radio network parameters cases_ppt-62.ppt
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Optimization of UMTS Radio
Network Parameters cases
Zte university
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Content
Optimization of Handover Parameters (Case 1)
Optimization of Handover Parameters (Case 2)
Optimization of Cell Reselection ParametersOptimization of Cell Radius
Optimization of HSDPA Performance (Case 1)
Optimization of HSDPA Performance (Case 2)
Optimization of Power Control Parameters
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3
Pilot Ec/Io of cell 1
time
Pilot
Ec/Io
Connect to cell 1 Event 1A Event 1C Event 1B
= add cell 2 = replace cell1 with cell 3 = remove
Pilot Ec/Io of cell 2
Pilot Ec/Io of cell 3
tt
t
Introduction of Soft Handover Algorithm
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Case Description
When the UE moves from thecoverage area on Shuqian
Road site (PSC: 436) to that
of Meihuacun Hotel site
(PSC:434), signals on
Shuqian Road site (PSC: 436)
deteriorate due to theblocking of the dual-deck
viaduct. However, the
Meihuacun Hotel site
(PSC:434) enters the active
set slowly for the highthreshold. Therefore, the
handover success rate is low.
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Adjustment Suggestion for Handover
Parameters
Adjust the handover threshold and Time to Trigger parametersof Event 1A and Event 1B: reduce the handover threshold andTime to Trigger parameters of Event 1A, so that cells withbetter signal quality can enter the active set as soon aspossible; raise the handover threshold and Time to Triggerparameters of Event 1B, so that cells within the active setwould be removed for sudden fading of signals.
Effect after the optimization:
After the optimization, cell 434 on Meihuacun Hotel site canspeedily enter the active set and cell 436 on Shuqian Road sitewould be removed from the active set due to the sudden fadingof signals. Drive test after the parameter adjustment shows thatthe success rate of handovers between Shuqian Road site andMeihuacun Hotel site is greatly improved.
Event Parameter Setting Before Optimization Setting After Optimization
Handover threshold 2dB 4dB
Time to Trigger 640ms 200ms
Handover threshold 5dB 7dB
Time to Trigger 640ms 1280ms
Event 1A
Event 1B
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Content
Optimization of Handover Parameters (Case 1)
Optimization of Handover Parameters (Case 2)
Optimization of Cell Reselection ParametersOptimization of Cell Radius
Optimization of HSDPA Performance (Case 1)
Optimization of HSDPA Performance (Case 2)
Optimization of Power Control Parameters
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Case Study (1)
The main serving cell of the UE is the third cell(SC53) of site BKC0074U, its Ec/Io is -9.83dB.
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Case Study (2)
As the UE moves on, the main serving cell changes to the third
cell (SC48) of site BKC0044U, its Ec/Io is -10.31dB. Cell SC53
of site BKC0074U is removed from the active set and enters
the monitoring set.
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Case Study (3)
After 1s, the signal quality of cell SC53 of site BKC0074U is stronger
than cell SC48 of site BKC0044U, and the Ec/Io of SC48 reaches -2.39dB. Cell SC48 reports to Event 1A and tries to enter the active set
again. At this moment, the pilot quality of the cell SC48 of site
BKC0044U is very bad, with its Ec/Io down to -21.05dB. The UE reports
to Event 1A, but cannot receive the handover command, then the call
drops.
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Optimization Solution
To avoid the condition that cell SC53 of siteBKC0074U cannot enter the active set after being
removed, the value of CellIndivOffset(utranCell) of
cell SC53 of site BKC0074U is changed from 0dB to
3dB to prevent the cell from being removed from the
active set.
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Verification of Optimization Effect (1)
The UE moves in the arrow direction in a call-hold mode, and its main serving
cell is cell SC53 of site BKC0074U.
Then the signal quality of cell SC53 of
site BKC0074U declines, with Ec/Io down
to -13.23dB, which is worse than that of
cell SC48 of site BKC0044U. Then, the
main serving cell of the UE changes to
cell SC48, but cell SC53 remains in the
active set.
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Verification of Optimization Effect (2)
In the end, the main serving cell of the UE changes back to cell SC53
as shown in the following figure, and no call-drop happens.
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Content
Optimization of Handover Parameters (Case 1)
Optimization of Handover Parameters (Case 2)
Optimization of Cell Reselection ParametersOptimization of Cell Radius
Optimization of HSDPA Performance (Case 1)
Optimization of HSDPA Performance (Case 2)
Optimization of Power Control Parameters
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Measurement Criteria for Cell Reselection
If Sx > Sintrasearch, the UE need not perform the intra-frequency
measurement.If Sx Sintersearch, the UE need not perform the inter-frequencymeasurement.
If Sintrasearch is not sent to the serving cell, the UE performs theinter-frequency measurement.
If Sx > SsearchRATm, the UE need not perform the measurementamong cells adopting different radio technologies.
If Sx
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Rs
Qmeas,s + Qhysts
RnQmeas,nQoffsets,n
The UE would sort all cells satisfying criteria S for cell selection based on their R values.
The optimal cell would have the highest R value. Within the Treselection threshold, if
the queuing order of a new cell is better than the current serving cell of the UE, and the
UE has been camped in this serving cell for more than 1s, then the UE would select
this new cell as its serving cell.
Cell Reselection Criteria
Cell queuing criteria R:
Rs: R value of the serving cell
Rn: R value of neighbor cells
Qmeas: measured value of the cell signals (for FDD cells, CPICH Ec/No orCPICH RSCP is adopted)
Qoffset1s,n: offset value between two cells (used when Qmeas of FDD cells isset to CPICH RSCP)
Qoffset2s,n: offset value between two cells (used when Qmeas of FDD cells isset to CPICH Ec/No)
Qhyst1s: hysteresis value (used when Qmeas of FDD cells is set to CPICHRSCP)
Qhyst2s: hysteresis value (used when Qmeas of FDD cells is set to CPICH
Ec/No) Treselection: value for the cell reselection timer
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Inter-RAT Reselection (Case 1)
Case Description
Wide coverage of 2G network: Frequent 2G/3G Ping-ponghandovers occur at the boundary of the 3G coverage area.
Case Study
Check all parameters of the 2G network. For all GSM cellsconfigured with 3G neighbor cells, set their Qsearch_Iparameters to 7, FDD_Qmin to 0, and FDD_Qoffset to 0.Qsearch_I=7 means that the inter-RAT measurement isperformed unconditionally. FDD_Qmin represents the signalquality of WCDMA cell, and works as one of the judging criteriafor cell reselection. For FDD_Qmin=0, 0 is a logic value, andthe corresponding absolute value is Ec/N0=-20dB.
In the 3G network, Qqualmin=-18, SsearchRAT=2, and
Qqualmin+ SsearchRAT=-16dB. Severe Ping-pong handovers exist within the GSM network,
the signals jitter greatly.
For 2G/3G co-site and co-antenna, the cell edges of 2G and3G cells overlap.
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Inter-RAT Reselection (Case 2)
Solution
Set FDD_Qmin of the corresponding 2G cells to 7, and thecorresponding absolute value is -12dB. Then the ping-pongeffect is solved.
Optimization Criteria
The cell reselection criterion at the 2G side must ensure thatwhen the UE is handed over to the 3G network, the signalquality of the 3G cells can support the UE. In this case, the cellreselection criterion is set to -12dB.
In the 3G network, Qqualmin=-18, SsearchRAT=2, andQqualmin+ SsearchRAT=-16dB. This setting ensures that theUE remains in the 3G network when 3G cells are available.
The reselection criterion changes the serving radius of the cell
to a certain degree. Thus, this parameter must be setreasonably.
Certain margin must be reserved for the bi-directionalreselection threshold to avoid the ping-pong effect. (In thiscase, the margin is 4dB.)
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Content
Optimization of Handover Parameters (Case 1)
Optimization of Handover Parameters (Case 2)
Optimization of Cell Reselection ParametersOptimization of Cell Radius
Optimization of HSDPA Performance (Case 1)
Optimization of HSDPA Performance (Case 2)
Optimization of Power Control Parameters
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Case Description
The RRC establishment success rate for the first cellof site PHGV is low. Usually less than 50% of the
RRC establishments are successful.
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Case Study
We trace the PMS measurement on the OMC, andthen we find that signaling of radio link addition
failure exists. Then it is found out that the cell radius
is set to 40km. In this condition, large amounts of UL
resources are consumed.
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Setting of Cell RadiusParameter name (Preamble Detection
Threshold, T) [dB]
Constant Value
[dB]
Pp-m
Block Size=1*168 Block Size=1*360
Cell radius
TTI=20ms
Message
Dual-antenna -24 -21 -2 1
Single-antenna -21 -18-2 1
TTI=10ms
Message
Dual-antenna -24 -21 1 4
Single-antenna -21 -181 4
Cell radius
TTI=20ms
Message
Dual-antenna -23 -20 -2 1
Single-antenna -20 -17-2 1
TTI=10ms
Message
Dual-antenna -23 -20 1 4
Single-antenna -20 -171 4
Cell radius
TTI=20ms
Message
Dual-antenna -23 -20 -2 1
Single-antenna -20 -17-2 1
TTI=10ms
Message
Dual-antenna -23 -20 1 4
Single-antenna -20 -171 4
Cell radius
TTI=20ms
Message
Dual-antenna -21.5 -19 -2 1
Single-antenna -18.5 -16-2 1
TTI=10ms
Message
Dual-antenna -21.5 -19 1 4
Single-antenna -18.5 -161 4
Note: Change the preamble detection threshold and initial TX power of the UE accordingly when changing the cell radius.
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Processing Procedure & Result
Set this parameter to 5km in urban, 15km in theedges, and 40km for isolated sites or sites providing
coverage for highways. Check the KPIs after the
changes, the RRC establishment success rate for
the first cell of site PHGV is greatly improved.
Begin time
Time
Granularity Cell Name Cell ID
RRC
Establishment
Success Rate
(Service)
Radio
Access
Success
Rate
2009-4-5 1 Week PHGV_Cell1 15401 56.66% 56.54%
2009-4-12 1 Week PHGV_Cell1 15401 38.91% 38.89%
2009-4-19 1 Week PHGV_Cell1 15401 99.43% 99.40%2009-4-26 1 Week PHGV_Cell1 15401 99.81% 99.80%
2009-5-3 1 Week PHGV_Cell1 15401 94.77% 93.79%
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Experiences
Cell radius would influence the UL coverage. The larger cell
radius is set, the larger the UL coverage and the search
window will be. Meanwhile, the consumed resources would
also increase. Therefore, the setting of cell radius would have
greater impacts on the system performance. The cell radius
must be set based on specific radio environment.
At the initial stage of the network construction, the number of
subscribers is small, then the cell radius can be set to a large
value to ensure the coverage. For network under commercial
operation, the site spacing becomes small. Under this condition,
a large cell radius would become meaningless, and it should
be adjusted based on the network construction condition. Notethat the random access parameter should be changed
accordingly.
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Content
Optimization of Handover Parameters (Case 1)
Optimization of Handover Parameters (Case 2)
Optimization of Cell Reselection ParametersOptimization of Cell Radius
Optimization of HSDPA Performance (Case 1)
Optimization of HSDPA Performance (Case 2)
Optimization of Power Control Parameters
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MPO Description
Parameter name HS-PDSCH Measurement Power Offset (dB)
Abbreviated name MeasPwrOffset
Description This parameter indicates the assumed HS-PDSCH power
offset relative to PCPICH/S-CPICH power used for CQImeasurement
Range and Step -613dB step 0.5 dB
Unit dB
Default Value 6
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MPO Adjustment and Testing Area
The test object is Cluster 11, MPO is changed from6 to 8, and the testing route is shown below:
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RSCP before and after Adjustment (1)
Before
After
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RSCP before and after Adjustment (2 )
Before
After
Best Aggr RSCP
0
10
20
30
40
50
0
500
1000
1500
20002500
3000
3500
4000
4500
5000
P er ce nt (% ) C um _N um be r
Percent(%) 20.82 45.01 27.85 5.95 0.37 0
Cum_Number 1984 4291 2654 567 35 0
(+INF, -
60.00) [-60, -70) [-70, -80) [-80, -90) [-90, -105) [-105, -INF)
Best Aggr RSCP
0
10
20
30
40
50
0
500
1000
1500
2000
2500
3000
3500
4000
4500
Percent(%) Cum_Number
Percent(%) 26.15 43.37 23.98 6.29 0.21 0
Cum_Number 2444 4054 2241 588 20 0
(+INF, -
60.00) [-60, -70) [-70, -80) [-80, -90) [-90, -105) [-105, -INF)
The comparison shows that MPOadjustment has little impact on
RSCP value.
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EC/IO before and after Adjustment (1)
Before
After
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EC/IO before and after Adjustment (2)
Before
After
After adjustment, Ec/Io reduces.
The occupancy of the value larger
than -8dB changes from 58% to
40%.
Best Aggr Ec/Io
0
5
10
15
20
25
30
35
40
45
0
5001000
1500
2000
2500
3000
3500
4000
Percent(%) Cum_Number
Percent(%) 18.46 21.5 40.56 16.15 2.6 0.73
Cum_Number 1725 2010 3791 1510 243 68
(+INF, -
6.00) [-6, -8) [-8, -10) [-10, -12) [-12, -14) [-14, -INF)
Best Aggr Ec/Io
0
5
10
15
20
25
30
35
40
0
500
1000
1500
2000
2500
3000
3500
P er ce nt (% ) C um _N um be r
Percent(%) 27.9 30.12 33.37 6.98 1.24 0.39
Cum_Number 2659 2871 3181 665 118 37
(+INF, -
6.00) [-6, -8) [-8, -10) [-10, -12) [-12, -14) [-14, -INF)
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Average CQI before and after Adjustment (1)
Before
After
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HSDPA Throughput before and after Adjustment (1)
Before
After
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Content
Optimization of Handover Parameters (Case 1)
Optimization of Handover Parameters (Case 2)
Optimization of Cell Reselection ParametersOptimization of Cell Radius
Optimization of HSDPA Performance (Case 1)
Optimization of HSDPA Performance (Case 2)
Optimization of Power Control Parameters
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HSDPA Handover AlgorithmUE
Target
Node B
Serving
Node B
Serving
RNC
1.Measurement Report
1D 2.Decide to
Change Serving
HS-DSCH Cell
NBAP NBAP
NBAP NBAP
3.Radio Link Reconfiguration
Prepare
4.Radio Link Reconfiguration Ready
NBAP NBAP 5.Radio Link ReconfigurationPrepare
NBAP NBAP
6.Radio Link ReconfigurationReady
7.ALCAP Iub Data Transport Bearer Setup(HS-DSCH)
NBAP NBAP
8.Radio LinkReconfiguration Commit
NBAP NBAP 9.Radio Link Reconfiguration Commit
RRC
RRC
RRC
RRC
10.Physical Channel Reconfiguration
11.Physical Channel Reconfiguration Complete
12.ALCAP Iub Data Transport Bearer Release(HS-DSCH)
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Event 1D Triggering Condition
Event 1D indicates that there is a cell outside the active set, which has
better quality than the cells in the active set, i.e., the best cell in theband changes. Upon the receiving of Event 1D, soft handover (cell
outside the active set reports Event 1D and the link number in the
active set does not reach its maximum), soft replacement (cell outside
the active set reports Event 1D and the link number in the active set
reaches its maximum) will be triggered or the best serving cell will
change (for HS-DSCH/E-DCH channel). When the cell satisfies the
following formula, and Time to Trigger duration is long, UE will report
1D to RNC.
/2HCIOLogM10CIOLogM10 1dBestBestNotBestNotBest
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HSDPA Handover
Impact on Download Rate
There are mainly two aspects:
Handover punctuality
Handover frequency
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Handover Punctuality Impact on Download Rate
HS-DSCH related physical channels do not support
soft handover. HS-DSCH services consume
relatively greater code resources, and HS-DSCH
transmission is based on packet scheduling and
does not support multi-cell transmitting data to one
subscriber. Therefore untimely handover will lead tothe deterioration of HS-PDSCH quality and the
decrease of CQI value reported by the UE, which
will result in a deterioration of the download rate.
Ensuring the timely handover is important forHSDPA download rate optimization.
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Handover Frequency Impact on Download Rate
HSDPA does not support soft handover, and services will be
interrupted shortly if cell update and channel handover are
initiated. Frequent hard handover will change HSDPA
download rate and the throughput. Therefore, reducing hard
handover is a primary method to increase HSDPA download
rate.
Reducing hard handover number and increasing handover
punctuality is contradictory, thats why too frequent Event 1D
will cause Ping-pong effect and reduce the download rate.
Therefore, the optimization of handover parameters will make
HSDPA download rate reach the highest value, and handover
frequency and punctuality become reasonable.
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Event 1D Related Parameters
In order to know Event 1D triggering threshold
impact on HSDPA download throughput, in intra-
frequency measurement we change hysteresis
value and Time to Trigger value and keep other
parameter value unchanged, the existing network
parameters relating to 1D are shown in the followingtable:
Parameter Value
PS domain intra-frequency measurement
event 1D Time to trigger320ms
PS domain intra-frequency measurement
event 1D Hysteresis3
PS domain HSPA global variables T1d 0ms
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Areas where Parameters are Changed
Areas are mainly office buildings and high-level residence quarters,
where population is dense. The coverage of single cells in the testedareas is favorable, as shown below:
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Parameter Modification Items
Parameter Name 1 2 3 4 5
PS domain intra-frequency
measurement event 1D Time
to trigger
320 320 320 320 320
PS domain intra-frequency
measurement event 1D
hysteresis
2 3 4 5 7
Parameter Name 6 7 8 9 10
PS domain intra-
frequency measurement
event 1D Time to trigger
640 640 640 640 640
PS domain intra-
frequency measurement
event 1D Hysteresis
2 3 4 5 7
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Testing Result and Analysis (1)
1 2 3 4 5 6 7 8 9 10
PS domain intra-
frequency measurementevent 1D Time to trigger
320 640 320 640 320 640 320 640 320 640
PS domain intra-
frequency measurement
event 1D Hysteresis
2 2 3 3 4 4 5 5 7 7
Average throughput
4341.
48
4197.
46
4429.
41
4298.
98
4400.
24
4484.
39
4369.
02
4376.
62
4371.
57
4352.
93
Rate of values lower than1Mbps 8.16 7.55 5.23 6.96 5.83 5.39 6.27 7 6.39 5.62
Best cell change times 104 94 96 80 92 69 89 72 84 64
Rate higher than 69.7 66.84 68.02 67.9 71.49 73.23 71.7 71.89 70.39 69.19
CQI 25 24.34 25.05 24.46 24.66 24.8 24.6 24.8 24.53 24.35
[3600, 2000) 16.26 19.11 21.63 18.75 17.39 16.53 16.99 15.85 17.9 17.81
[2000, 1024) 5.88 6.5 5.12 6.39 5.29 4.85 5.04 5.26 5.32 7.38
[1024, 0) 7.61 6.04 4.42 6.03 5.22 5.15 5.51 6.13 5.26 5.08
[0, -INF) 0.55 1.51 0.81 0.93 0.61 0.24 0.76 0.87 1.13 0.54
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Testing Result and Analysis (2)
HSDPA Throughput&Event 1D parameter
8.16 7.55 5.23 6.96 5.83 5.39 6.27 7.00 6.39 5.62
104
94 96 92
69
89
72
84
6469.7
66.84 68.02 67.9 71.49 73.23 71.7 71.89 70.39 69.19
25.00
80
24.3524.5324.8024.6024.8024.6624.4625.0524.34
4341.48
4197.46
4429.414400.24
4484.39
4369.02 4376.62 4371.57 4352.934298.98
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
90.00
100.00
110.00
2-320 2-640 3-320 3-640 4-320 4-640 5-320 5-640 7-320 7-640Event 1D Hystereris in intra-measurement
Percent
%
4000.00
4100.00
4200.00
4300.00
4400.00
4500.00
4600.00
4700.00
4800.00
4900.00
5000.00
5100.00
AverageThroughput
Scale of less then 1Mbps Times of best cell change Scale of more then 3.6Mbps
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Test Comparison Result (1)
DT data shows that when hysteresis value is 4 and
Time To Trigger is 640ms, the performance is the
best: downloading rate is 4.484Mbps; handover
number is 69 which is a relatively small number;
average CQI value is 24.80 which indicates that it
has a good downlink service channel quality and thehandover is timely.
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Test Comparison Result (2)
Parameter 3 Parameter 4
Parameter
Modification
PS service intra-frequencymeasurement event 1D
Time to trigger
320 640
PS service intra-frequency
measurement event 1D
Time hysteresis
3 3
HSDPA
Average throughout 4429.41 4298.98
Rate of values lower than
1Mbps5.23 6.96
Best cell update number 96 80
Rate of values higher than 68.02 67.9
CQI 25.05 24.46
When configuring parameter 4, handover number is 80, but CQI reported by UE is 24.46,
and throughput is 4.29mbps, which indicate that the handover is unpunctual, and the
primary serving cell is not the best cell. When configuring parameter 3, handover number
is 96, but CQI reported by UE is 25.05, which indicate that the handover is punctual, and
the primary serving cell is the best cell, and the rate is higher than that of parameter 4.
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Test Comparison Result (3)
Parameter 1 Parameter 3 Parameter 6
Parameter
modification
PS domain intra-
frequency measurement
event 1D Time to trigger
320 320 640
PS domain intra-
frequency measurement
event 1D hysteresis
2 3 4
HSDPA
Average throughput 4341.48 4429.41 4484.39Rate of the value lower
than 1Mbps8.16 5.23 5.39
Best cell update number 104 96 69
Rate of the value higher
than69.7 68.02 73.23
CQI 25.00 25.05 24.80
Keep the primary serving cell with good coverage, because frequent
handovers will affect the throughput. When CQI is relatively low, less
handover number will lead to a higher rate.
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Handover
Impact on Download Throughput
To explain handovers impaction downloading throughput, we select parameter
1 (2320) and parameter 6 (4640) to be set in a small scenario to make acomparison.
In the area, the handover number of parameter 6 is smaller than that ofparameter 1, but throughput and CQI increase, which indicates that reasonablehandover number and area are good for throughput increment.
Average throughput is 4474.33Kbps and average CQI
is 25.22 (parameter 6)
Average throughput is 4352.98Kbps and average
CQI is 24.85(parameter 1)
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Parameter Configuration at Crossroads 1
Left Right
Para
Hysteresis 4 3
Time To Trigger 640 320
Throughput 4.157Mbps 4.256Mbps
CQI 23.97 25.34
If the parameter configuration is (4
640ms), the test shows that it brings a good result,but at crossroads, the testing result is not the best, and parameter configuration (3.
320ms) can bring good testing result.
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Parameter Configuration at Crossroads 2
Signals at the corner changes swiftly, and signalsare easily mutated, which requests UE to quicklyrespond to the change of signals. Comparativelysmall hysteresis and Time to Trigger can satisfy therequirement. As shown in the experimental result,CQI of configuration (3,320) is higher than that ofconfiguration (4, 640) , i.e., configuration (3,320) canbetter satisfy the quick handover requirements atcrossroads.
From above, conclusion can be made: handover
parameter configuration is closely related to theradio environment. Handover parameters shall bechanged according to the radio environment, thusnetwork optimization can achieve the best result.
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Experiences
The method to control handover number is to adjust Event 1D
triggering threshold. Through Event 1D threshold adjustment,handover punctuality can be guaranteed and handover
frequency can be reduced, and the target of HSDPA handover
optimization is reached.
From the test, we can see in dense urban area, hysteresis
value shall be set to 4 and Time To Trigger to 640ms.
Radio environment is varying. We shall configure the handover
parameters based on the actual environment to ensure that
UEs handover is performed at proper time and that the
download rate is the highest.
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Content
Optimization of Handover Parameters (Case 1)
Optimization of Handover Parameters (Case 2)
Optimization of Cell Reselection Parameters
Optimization of Cell Radius
Optimization of HSDPA Performance (Case 1)
Optimization of HSDPA Performance (Case 2)
Optimization of Power Control Parameters
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FACH Power Modification
In P project, RRC connection setup success rate is relatively
low. Take RNC203 to make a test, and change MaximumFACH Power (dB) from 1.0 to 2.5.
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RRC Connection Setup Success Rates
Make observance of RRC connection setup success
rate for four days, and find that 0.45% increase is
obtained, as shown below:
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Other Indicators - TCP
KPI November 10 November, 20
Maximum Cell TCP>95% 15 28
Average Cell TCP 18.50% 19.50%
Number of rejected services,
DCH downlink TCP limit
1884 2709
Average Cell TCP increases due to the increase ofthe number of the rejected TCP limit service.
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Other Indicators - Call Drop Rate
Call drops and little fluctuation of the traffic volume
is quite normal, as shown below:
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Conclusion and Suggestions
Case Conclusion:
Generally if FACH power is increased to 2.5dB, RRCconnection setup success rate is increased by 0.45%,and other indicators are quite normal.
Suggestions: 1. ACH power can be set too high, which will lead to
the waste of the downlink power resources and bringinterference to other radio links.
2. Its recommended that FACH power is not changed.
If RRC connection setup rate is comparatively low, tryincreasing FACH power gradually upon demands, andthe change of RRC connection setup success rateand other indicators shall be carefully observed at alltimes.
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