CQI feedback periodicity

[mobilink999]

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]

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]

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]

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]

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]

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]

Hello Minto,
The initial value was 2ms

[mobilink999]

Moh700ah: Please donot post irrelevant info we all know what us CQI

romagdinio: I agree with your observation we also found improvment. However low reported CQI affected any throughput ??

[white_Noise]

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]

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 !!