- This topic has 2 replies, 1 voice, and was last updated 4 years, 4 months ago by Optimizer.
17th June 2013 at 11:53 #69080SamGuest
Could you please help to debug problem on few cells in BSC. We have few cells where Sd drop is high due to other reason. We took all possible action as follow:-
Concentration factor change;
HW checks- DRU/TRU/RUS/CDU replacement (depends on site, different sites-different RBS and HW)
Bird test (Antenna and Feeder check/replacement);
Transmission check (DIP status check, NES-SES error checks, Rblt restart was provided);
Grounding checks and fixed;
Still there was no improvement 🙁
When we dig further we see these cell has high CLUNDROP count which correspond to Sd drop reason other. Interesting fact is that this cell belong to center of BSC with no location border. Neither this cell overshoots. Since we have 3G we thought it could be location update with 3G, we deleted all active IDLE UMFI list. Still there was no change.
Can somebody please suggest if faced this problem ??17th June 2013 at 18:45 #69081pixGuest
what is the “standard” SDCCH drop rate ?
what is the SDCCH “LU” drop rate ?
please provide hourly values for one typical day.
Even though you are not in location area Border, the MS are still doing LU. Could you compare the amount of LU done in this cell, compared to the immediate neighbour ? Do you see a big difference ? Values should be comparable, assuming the number of idle MS is similar in both cells.
If you do see a difference, you may assume that the LU received by your “bad” cells are “fake”.
1/ changing the BCCH/BSIC
2/ reduce MAXTA
As you suggested, the problem might come from 3G. But the LU are due to MS leaving the 3G and falling back to the 2G. Not the opposite –> you must set your UMFI IDLE to proper values.
In your 3G cell, check out the number of reselection from 2G to 3G (such counter exist in E/ 3G and in ALU 3G). Are they high ?
If yes, then it looks like some ping pong is occuring between 2G and 3G.
Those are all the ideas I have so far. Waiting for some numerical examples….
Pix1st September 2016 at 11:34 #69082OptimizerGuest
i face the same problem in my network, not only one BSC, but the whole network, high SDCCH drop due to others, CNDROP is very high due to others.
CLUNDROP is high and sometimes CNDROPSMS suddenly goes up sharply for some cells for days, then goes back to normal performance with no action, all cells are not in LA border, i had tried all the solutions done by Sam, we have only 2G network, so no ping pong between 2G and 3G.