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Security
Level:
HUAWEI TECHNOLOGIES CO., LTD.
HSDPA Throughput Optimizatio
n
HSDPA Basic
High Speed Downlink Packet Access
Maximum Throughput 14.4Mbps
Physical Channel
HS-SCCH
HS-SCCH
HS-PDSCH
HS-PDSCH
HS-DPCCH
HS-DPCCH
High Speed Shared Control Channel
High Speed Physical Downlink Shared Channel
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HSDPA Basic
AMC
Fast Scheduling
HARQ （ Hybrid ARQ ）
16QAM
SF16, 2ms and CDM/TDM
3 New Physical
HSDPA Throughput
"=3.84 /SF *(Modulation* Code* Coding
rate)"
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Flexible scheme power allocation
Time
Total Power
HSDPA Available power
Allocated to CCH Power
DPCH Power
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HSDPA Rate
The TTI is 2 ms. So for example Cat
10 can decode 27952 bits/2 ms =
13.976 MBit/s (and not 14.4 MBit/s as
often claimed incorrectly).
CQI
CQI
value
Transport
Block
Size
Number
of
HS-PDSCH
Modulation Reference
power
adjustment
NIR
XRV
0 N/A 1 137 1 QPSK 0 2 173 1 QPSK 0 3 233 1 QPSK 0 4 317 1 QPSK 0 5 377 1 QPSK 0 6 461 1 QPSK 0 7 650 2 QPSK 0 … … … … … 12 1742 3 QPSK 0 13 2279 4 QPSK 0 14 2583 4 QPSK 0 15 3319 5 QPSK 0 16 3565 5 16-QAM 0 ... ... ... … … 21 6554 5 16-QAM 0 22 7168 5 16-QAM 0 23 9719 7 16-QAM 0 24 11418 8 16-QAM 0 25 14411 10 16-QAM 0 26 17237 12 16-QAM 0 … … … … 0 30 25558 15 16-QAM 0 Out of range 28800 0HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 9
Steps :
Check Iub utilization (standard < 75%)
Check DL power utilization
(standard < 75%)
Check UL CE utilization
(standard < 75%)
Check DL CE utilization
(standard < 75%)
Check OVSF code utilization
(standard < 75%) Check UL RTWP (standard < -96 dBm) Star t Any hardware or transmissi on instability? Solve instabilit y Steps :
Check detail alarm and escalate to related PIC
Follow up rectification progress Monitor HSDPA throughput
after instability clear Low HS payload? (standar d < 30 Mbits/da y) YES NO Analyze on Low HS Payload Check if CS traffic of same cell or colocated F1 also low Analyze CQI distributi on Steps :
Check CQI distribution over same period
Get average CQI value (standard >22)
Correlate trend of reported CQI with HS throughput to find relation
Investigate if low throughput was caused by low CQI
YES NO Low throughput because of low CQI ?
Investiga
te RF
issue
Steps : Perform TP analysis to check if cell overshoots, poor coverage, bad indoor penetration,etc Check if current target coverage is proper or not
Check CPICH power balanced or not Check any CPICH
change activity
Perform drive/walk test (optional)
Conduct site audit and take action if required
Analyze HS & UL R99 RAB SR YES NO Steps :
Check HS and UL R99 RAB SR
Check reason of RAB blocking
Correlate trend of HS & UL R99 RAB SR with HS throughput to find relation Low through put because of RAB blocking ? Tune parameter of Cell Admission Control YES NO Steps :
Perform parameter audit on related CAC part (e.g FTI, power CAC, HW adm, DL code
adm,etc)
Adjust parameter setting to proper value
Verification of impact (check overall KPI also)
Analyze capacity utilization Radio capacity need to be expande d ?
Conduct cell trace for further investigation YES NO Steps : Check retransmisión, scheduled throughput, served throughput
Check used CQI, reported CQI
Check HSPA cell change frequency Check throughput interuption characteristic Finish
Request
for
expansion
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(A)Action4. Check Downlink Power Resour
ce
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(A)Action5. Check Downlink Code Resourc
e
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LST UCELLHSDPA (RNC)
(A)Action6. Check Iub Bandwidth
Physical BW (AAL2PATH or IPPATH)
HSDPA PATH Configuration
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(A)Action7. Check Iub Packet Loss Rat
e
UMAT check RLC layer Retransmission (RB.UsDlRetranRat
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(B)Action8. Check Channel Quality
Check CQI by DT Tool
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(D)Action11. Check Access Signaling
1.
Start UE Trace by LMT
2.
Check info hsdsch-physical-layer-category identifying the UE capacity
in RRC_CONNECT_SETUP_CMP message, whether UE capability meets r
equirement. (CAT8 – 7.2Mbps; CAT10 – 14.4Mbps; CAT14 – 21Mbps)
3.
Check info MaxBitRate in RANAP_RAB_ASSIGNMENT_REQ message (Ext
endedMaxBitRate for HSPA+). If not meet requirement, need to check
Laptop AT command
Subscription information of USIM in HLR
Max rate in SGSN and GGSN
Whether License supported
LST CELLALGOSWITCH: Cell Hspa Plus Function Switch_L2ENHANCED & 6
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(E)Action14. Check CPU Usage of Lapt
op
Check CPU usage of laptop during data transmission.
If high (>90%) the response message to RLC layer or TCP
layer are transmitted in a low rate, which cause the wind
ow restriction.
(E)Action15. Check Online HSDPA Use
r
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Thank you
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Copyright©2011 Huawei Technologies Co., Ltd. All Rights Reserved.
The information in this document may contain predictive statements including, without limitation, statements regarding the future financial and operating results, future product portfolio, new technology, etc. There are a number of factors that could cause actual results and developments to differ materially from those expressed or implied in the predictive statements. Therefore, such information is provided for reference purpose only and constitutes neither an offer nor an acceptance. Huawei may change the information at any time without notice.
