wcdma-kpi monitor and optimization
DESCRIPTION
WCDMA-KPI Monitor and OptimizationTRANSCRIPT
Resource KPI monitor and optimization
Content
Resource KPI monitor introduction
DL power monitor and optimization
UL capacity monitor and optimization
Code resource monitor and optimization
CE resource monitor
P project KPI monitor and optimization
One reason for resource limitation is number of 3G user increase, and operator changing fee decrease also lead to the increase of average erlang. For example HK user average erlang cold be up to 0.5E.
The other reason is the strategy for NW design is focus on user feeling and KPI but not system capacity.
P project CS NW daily erlang chart
Single user erlang could be 0.45erl on BH ：
P project NW hourly CS erlang chart
Accident could lead to resource limitation for some area:
Subscriber action lead to resource limitation for some sites
Resource KPI and threshold
Resource KPI mainly include DL power, UL capacity, code resource and CE resource.
Resource Type KPI id and name threshold
TCP
C301320150 Number of rejected services,DCH downlink TCP limit 50
PI30167 Average non-HSDPA TCP 40%
PI30092 Maximum Cell TCP (%) 100%
PI30093 Average Cell TCP 70%
UL TrafficPI30029 Handover Blocking Rate 0.5%
KPI RTWP （ in busy hour ） -98dBm
Code
C301320153 Number of rejected services, DCH no code 50
PI30205 Average Cell HSUPA Users 12
PI30172 Cell Average HSDPA Users 16
CEPI301830006 Maximum use Ratio of Uplink NodeB CE 60%
PI301830010 Maximum use Ratio of Downlink NodeB CE 60%
Related KPI
Content
Resource KPI monitor introduction
DL power monitor and optimization
UL capacity monitor and optimization
Code resource monitor and optimization
CE resource monitor
P project KPI monitor and optimization
RNC TCP limitation with CS call drop2009-06-09 RNC Call Drop Rate,CS Traffic Volume, CS AMR(Erl)
Number of rejected services,DCH downlink TCP limit
00:00:00 01:00:00 1.24% 851.54 56
01:00:00 02:00:00 1.07% 481.2097 22
02:00:00 03:00:00 1.09% 253.1742 12
03:00:00 04:00:00 0.70% 134.0175 5
04:00:00 05:00:00 0.61% 84.9817 11
05:00:00 06:00:00 0.54% 66.0458 11
06:00:00 07:00:00 0.64% 102.6633 31
07:00:00 08:00:00 1.06% 259.94 235
08:00:00 09:00:00 1.31% 658.3644 2262
09:00:00 10:00:00 1.11% 1242.4528 1875
10:00:00 11:00:00 0.91% 1798.6944 3261
11:00:00 12:00:00 1.04% 2266.3008 7064
12:00:00 13:00:00 1.09% 2629.905 8398
13:00:00 14:00:00 0.99% 2488.7411 3719
14:00:00 15:00:00 1.05% 2494.8219 7936
15:00:00 16:00:00 1.05% 2598.1903 10515
16:00:00 17:00:00 1.16% 2762.4531 11489
17:00:00 18:00:00 1.20% 2930.3844 9926
18:00:00 19:00:00 1.45% 3336.4133 22875
19:00:00 20:00:00 1.29% 2674.1925 5196
20:00:00 21:00:00 1.04% 1946.7989 1288
21:00:00 22:00:00 1.13% 1858.4106 616
22:00:00 23:00:00 1.32% 1818.2567 575
23:00:00 00:00:00 1.35% 1445.835 216
Number of rejected services,Handover
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2009-6-12 6 1 1 0 0 0 0 2 22 99 556649108471821954108121201760 66 9 19 13
2009-6-17 0 2 0 0 0 0 2 0 6 28 113187252 95 214261285367643 86 10 11 4 3
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modify reserve HSDPA power
According to system algorithm MinHsdpaPower （ MinHspaPwrRto ） +NoHsPower >Node B
admission threshold （ MinHsdpaPower stands for HSDPA reserved power ）， DL congestion control will start (downgrade DL DCH rate) 。
MinHspaPwrRto default value is 20% ， HK P project is 10% before cut over
fast downgrade speed
Because high load cell often be with high admission failure, normally we should fast downgrade to release radio resource ASAP. Avoid handover user could not handover in the cell then call dropped.(this action is only take effect in cell with much more PS users, if all users in the cell is in CS service. It will not take effect).
Abbreviated Name
Parameter name Range and Step
Current Value
Update value
remark
UlDnMaxStg
Maximum Number of Degraded Uplink Load Steps Every Time
[1, 8] 1 2 Downgrade from 384kbps to 16kbps
DlDnMaxStg
Maximum Number of Degraded Downlink Load Steps Every Time
[1, 8] 1 3 Downgrade from 384kbps to 8kbps;
Abbreviated Name
Parameter name
Current Value
Update value
remark Modify purpose
PRamp ( Power Ramp Factor)
0.2 0 B class parameter, service related parameter, all service sub-class must be modified.
Decrease TCP congestion rate
DlEbN0 (Downlink Traffic Eb/N0)
7.5 5.1 B class parameter ， service related parameter, modify 13.6K signaling only (service class 5)
Reduce TCP Limit
B class parameter modification
Through decrease Power up factor or decrease DL Eb/No could both lead to reduced congestion, While we need detailed evaluation to avoid some other bad effect. Table showed P project record for the modification, and can be consider as the reference. ZTE engineering experience showed downgrade Eb/No for 13.6K signaling channel could reduce TCP limitation effectively, while the performance of Access will not be affect so much.
Modify result
Through modify HSDPA reserve power and downgrade speed, Rejection rate for TCP limited decrease 50%.
Through B class parameter modification, TCP limited time decrease to 10%.
Content
Resource KPI monitor introduction
DL power monitor and optimization
UL capacity monitor and optimization
Code resource monitor and optimization
CE resource monitor
P project KPI monitor and optimization
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Cel l Cal l Drop Rate, CS1 Cel l Cal l Drop Rate, CS2
UL capacity limitation
Call drop rate increasing not means UL capacity limitation, but call drop increasing is the most common scene for limitation. Because call drop rate is most cared KPI, and be observed every day.
HK UCE site call drop rate
RTWP increasing is the most directly representation for UL limitation, while sometimes reason for RTWP increasing could be external interference. And it’s hard to eliminate this reason.
HK UCE site RTWP
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Maxi mum RTWP(dBm)1 Maxi mum RTWP(dBm)2
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Cel l Traffi c Vol ume, CS(Er l )1 Cel l Traffi c Vol ume, CS(Er l )2
Erlang is determining factor for UL limitation either. There are many factors related to the erlang of a cell. Normally we should care for cell capacity, if erlang in a cell exceed 20 erlang in BH.
HK UCE site CS erlang
UL Power control parameter modification
The quality of users will be down as a consequent of capacity increasing. Optimization will do trade-off between capacity and quality.
HK P project UL power control parameter modification
Abbreviated Name
Parameter meaning
Modification object Current Value
new value effect
ULINITSIR Uplink Initial SIR target (dB)
上行 3.4k/13.6k 信令，上行 12.2k AMR
4-5 3.5 Obviously
ULMAXSIR Maximum Uplink SIR target (dB)
上行 3.4k/13.6k 信令，上行 12.2k AMR
15 10 Obviously
B class parameter
BLER Period Factor/Tolerance BLER Period
上行 3.4k/13.6k 信令，上行 12.2k AMR
2/250 1/70 Obviously
UlSirTargDnStep
Uplink SIR Target Down Step Size (dB)
上行 3.4k/13.6k 信令，上行 12.2k AMR
0.1 0.2 A few improvement
VIP cell optimization for UL capacity
Through UL power control parameter optimization we can improve RTWP increasing, but some cells will be in trouble for user increasing. And further
modification to SIRtarget will affect subscriber feeling. For this case ZTE suggest to define another set of power control parameter
which is special for these high load cells. The following table is comparison of parameters for special site and parameters for normal site.
Power control parameters for High load cell
SRVTYPE ULINITSIR ULMAXSIR ULMINSIR
0 3.5->1.5 10.0->3.5 2.0->1.0
104 4.0->2.0 15.0->5.0 0.5->0
28 3.5->1.5 10.0->3.5 0.5->0
50 6.0->2.0 15.0->5.0 2.0->0
54 6.0->2.0 15.0->5.0 2.0->0
through modification of power control parameter, call drop rate decrease to 25%.While BLER increase obviously.
UCE Site call drop after refer to new power control parameter.
through modification of power control parameter, call drop rate decrease to 25%.While BLER increase obviously.
UCE site BLER after refer to new power control parameter.
Content
Resource KPI monitor introduction
DL power monitor and optimization
UL capacity monitor and optimization
Code resource monitor and optimization
CE resource monitor
P project KPI monitor and optimization
Code resource KPI monitor and optimization ：
Through observing "Number of rejected services, DCH no code” we could know cell is in code limitation. Also “average code resource usage” and “HSDPA user number” could be factor for determination and optimization. We could modify the code allocation to reduce code limitation.
OcuRateNoHspdsch + OcuRateHspdsch + DpchCodeHy + 32 <= 512 formula 1
OcuRateNoHspdsch + OcuRateHspdsch + CodeUptHyA > 512 formula 2
“OcuRateHspdsch” is the number of code (SF=512) which is blocked by the code occupied by HS-PDSCH channel
“OcuRateNoHspdsch” is the number of code (SF=512) which is blocked by the code occupied by not HS-PDSCH channel
“DpchCodeHy” is the number of code (SF=512) reserved for DPCH channel, “CodeUptHyA” is the threshold to determine if we need decrease HS-PDSCH channel number.
When formula1 is fulfilled NO. of HS-PDSCH +1; When formula 2 is fulfilled NO. of HS-PDSCH -1.
To assure R99 user accessibility, the modification is apply to P project.
Site WTR code resource limitation
Abbreviated Name
Parameter name
Range and Step
Current Value
Update value
remark
DpchCodeHy DPCH Code Hysteresis
0..512 16 28 To decrease the number of rejected services for DCH no code
CodeUptHyA Code Update Hysteresis A
0..512 16 28 To decrease the number of rejected services for DCH no code
HSDPA data flow will be affected after modification on code allocation algorithm
Site WTR HSDPA MAC data volume
Content
Resource KPI monitor introduction
DL power monitor and optimization
UL capacity monitor and optimization
Code resource monitor and optimization
CE resource monitor
P project KPI monitor and optimization
By now there is no CE resource limitation in P project, we have 2 threshold:
CE
PI301830006 Maximum use Ratio of Uplink NodeB CE
60%
PI301830010 Maximum use Ratio of Downlink NodeB CE
60%
Content
Resource KPI monitor introduction
DL power monitor and optimization
UL capacity monitor and optimization
Code resource monitor and optimization
CE resource monitor
P project KPI monitor and optimization
Besides parameter modification has been mentioned, Properly plan pilot power, adjust erlang area, adjust handover area, reduce pilot pollution could all be consider as solutions for capacity.
