HSDPA low CQI and Code occupancy problems

[nabil el haddani]

Hi experts,

I have a serious problem on some cells with low CQI even if the RF conditions are good. In other hand the ave_code_occupancy is very high!! (More than 80%°) even if they are low traffic cells.

the HW and RAN parameters have been checked and everything is fine.

Anyone can light my way how to detect why i have such bad CQI and average code occupancy!!!

Br,

Nabil

[gprastomo]

Hi experts,

I have a serious problem on some cells with low CQI even if the RF conditions are good. In other hand the ave_code_occupancy is very high!! (More than 80%°) even if they are low traffic cells.

the HW and RAN parameters have been checked and everything is fine.

Anyone can light my way how to detect why i have such bad CQI and average code occupancy!!!

Br,

Nabil

Hi,

Low CQI could be caused by bad channel quality measured by MS and sent to network to RNC.
In some release of RNC (NSN RU 10) there is modified CQI that makes the reporting CQI has lower value than real CQI by applying some offset. You have to make sure that there is no pilot pollution, no radio problem appear on that cell.
About the high code occupancy, activating HSDPA 3.2 Meg will utilize ~34% of code, 7.2 will utilize ~68% of code etc.
Activating the feature such as 48 or 96 HSDPA user per cell will also utilize the code (let say the 16 kbps UL HSDPA return channel is not activated, so RNC will allocated 64 kbps code and CE multiply by max 48 or 96 user) so it will utilize the code as well. On the other hand is, we have to make sure that there is small number of SHO overhead.

thanks

[mobilink999]

Dear Nabil as far as I know CQI and code occupancy are not directly correlated. Try giving your BTS hard reset. Place yourself in main lobe and try to expose MS and move it and observe if there is any change of CQI. I have observed that if u leave your data card in car hanging from laptop CQI doesnt go more than 25 or 26. Try to bring it near window.
Now the other thing is as my friend mentioned check in detail for radio condition. good rscp is not as important but good EcNo is very imp. you can get 29 CQI even in 90s rscp. Also check if you have tempered with your handset firmware??? whats your handset category....still the best place to start troubleshooting is to reset BTS :)

[wolverine]

Also if you are having SHO problems as per your previous post, this can also cause poor CQI as the HS-PDSCH cannot be in SHO and any adjacent neighbour channels are seen as interferers..

[cococrunch]

Regarding code congestion, also one thing to check is the no. of codes for HSDPA activated?