View Full Version : CQI feedback periodicity
mobilink999
2012-12-18, 05:07 PM
Hi All,
I was reading CQI reportting periodicity and its impact in LTE thuput trouble shooting. The concept I used from UMTS CQI. In huawei I modified feedback paramter. from 2 ms to 6 and 8 ms. I got some improvent in PS drop and accessibility. I want to correlate theory with observation. I chnged CQIFbCk and CQIFbCkforSHO for some cells of which some showed marked improvment. Can kindly someelse also trial it and share his findings ??
romagdinio
2012-12-20, 08:35 PM
Hello,
we tried to increase the CQI feedback timer in our network to 8ms as well and it gave good improvement in the Accessibility & Retainability KPIs for the highly loaded sites, as the new setting will decrease the periodicity of reporting the CQI value by the UE & hence it will reduce the Uplink interference levels (RTWP level). However this setting will affect the CQI values, we monitored an significant degradation in the average reported CQI values by the UE.
MINTO
2012-12-20, 10:43 PM
Hello,
we tried to increase the CQI feedback timer in our network to 8ms as well and it gave good improvement in the Accessibility & Retainability KPIs for the highly loaded sites, as the new setting will decrease the periodicity of reporting the CQI value by the UE & hence it will reduce the Uplink interference levels (RTWP level). However this setting will affect the CQI values, we monitored an significant degradation in the average reported CQI values by the UE.
hi romagdinio, how much was the initial value, for some vendors like E******* its a system constant value ( default=10ms)..also d u use both periodic and aperiodic??
Moh700ah
2012-12-22, 01:55 AM
CQI (Channel Quality
Indicator)
This provides an indication of the downlink channel quality and effectively
identifies an optimum modulation and coding scheme for the eNB to use. There
are various coding options for the CQI; Figure 2-124 illustrates the main CQI
index.
Moh700ah
2012-12-22, 01:56 AM
CQI Index
Modulation
Code Rate x 1024
Efficiency
0
out of range
1
QPSK
78
0.1523
2
QPSK
120
0.2344
3
QPSK
193
0.3770
4
QPSK
308
0.6016
5
QPSK
449
0.8770
6
QPSK
602
1.1758
7
16QAM
378
1.4766
8
16QAM
490
1.9141
9
16QAM
616
2.4063
10
64QAM
466
2.7305
11
64QAM
567
3.3223
12
64QAM
666
3.9023
13
64QAM
772
4.5234
14
64QAM
873
5.1152
15
64QAM
948
5.5547
Moh700ah
2012-12-22, 01:57 AM
Feedback Reporting
In order to optimize the system’s performance, the UE can provide various feedback information about the radio channel environment. LTE has various feedback reporting options which depend on the MIMO and eNB configuration. The reporting may consist of the following elements.
romagdinio
2012-12-23, 03:20 AM
Hello Minto,
The initial value was 2ms
mobilink999
2012-12-23, 05:45 PM
Moh700ah: Please donot post irrelevant info we all know what us CQI :p
romagdinio: I agree with your observation we also found improvment. However low reported CQI affected any throughput ??
white_Noise
2012-12-25, 07:46 PM
Hi All,
I was reading CQI reportting periodicity and its impact in LTE thuput trouble shooting. The concept I used from UMTS CQI. In huawei I modified feedback paramter. from 2 ms to 6 and 8 ms. I got some improvent in PS drop and accessibility. I want to correlate theory with observation. I chnged CQIFbCk and CQIFbCkforSHO for some cells of which some showed marked improvment. Can kindly someelse also trial it and share his findings ??
Can you please share the MML command? is it in the Inner CFGMML? as I'm not able to find it in the CFGMML and not able to generate the cell command in the offline Web LMT !!
white_Noise
2012-12-25, 07:48 PM
Hi All,
I was reading CQI reportting periodicity and its impact in LTE thuput trouble shooting. The concept I used from UMTS CQI. In huawei I modified feedback paramter. from 2 ms to 6 and 8 ms. I got some improvent in PS drop and accessibility. I want to correlate theory with observation. I chnged CQIFbCk and CQIFbCkforSHO for some cells of which some showed marked improvment. Can kindly someelse also trial it and share his findings ??
Hi All,
I was reading CQI reportting periodicity and its impact in LTE thuput trouble shooting. The concept I used from UMTS CQI. In huawei I modified feedback paramter. from 2 ms to 6 and 8 ms. I got some improvent in PS drop and accessibility. I want to correlate theory with observation. I chnged CQIFbCk and CQIFbCkforSHO for some cells of which some showed marked improvment. Can kindly someelse also trial it and share his findings ??
Can you please share the MML command? is it in the Inner CFGMML? as I'm not able to find it in the CFGMML and not able to generate the cell command in the offline Web LMT !!
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