SDCCH Drop

Hi Atheer,

Is ciphering enabled or disable at BSC and MSC end for both the cases.

hi,

The T3101 is supervising the paging retransission. I can’t find a correlation between SDR and PSR, but please correct me if i’m wrong.

First thing to do is to find the cause of SDR. Timing Advance ? Bad Quality ? Bad Level ?

Activate the SDCCH HO. Doing so will give you precise counter regarding SDCCH HO CAUSE, which will help you diagnose the main issue.

Put 2 SDCCH on the TRX0 (bcch) only.
Then put 1 SDCCH on the TRX1, and 1 SDCCH on BCCH TS.

Then compare SDR between those two configuration.

If available, check the SDR per TRX.

Check the path imbalance.

Check the VSWR.

Also, the cells may be located at a MSC border ? I’m not familiar with this issue, but if you do a drivetest, you may be able to see things more clearly : call setup can’t go through when the MS has just changed MSC area. (to be verified)

Regards,

Pix

Hi everybody,
we had a case with high sdcch drop in a cell. The hoping type was BBH. We changed to Non Hoping in order to check which TRX is mostly interfered. According to KPIs there is no interference. But, with the Non Hoping activated sdcch drop was decreased and quality improved. Any idea, what could cause the increase of sdcch drop with BBH and improvement (decreasing) of sdcch drop with NH? Changing TRXs didn’t help, vendor is ALU.
BR,
Rex