- This topic has 7 replies, 1 voice, and was last updated 11 years, 6 months ago by pix.
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28th June 2013 at 11:17 #69102RicardoGuest
I am having very strange issue occuring randomly over the network (ALU 2G), whever a dip in RTCH availbility is observed due to transmission or power outage, cell starts suffering from Radio+HO drops. Below are some observations
– Complete site (all 03 sectors ) went down due to TXN/Power and after restoration CDR (Radio+HO) of one or two cells will be degarded
– in some cases site itself will be OK but front facing neigbor CDR will be degarded after dip in RTCH
– We have performed complete parameter Audit & complete health check from BSS side.Need your support
29th June 2013 at 06:43 #69103LemaureGuest– Complete site (all 03 sectors ) went down due to TXN/Power and after restoration CDR (Radio+HO) of one or two cells will be degarded
ITt may be that the rate of drop is high because the number of calls just after power restoration is low.
– in some cases site itself will be OK but front facing neigbor CDR will be degarded after dip in RTCHthe design of front facing neigbor wasn’t actually prepare to handle such calls (nor the nieghborhood). Their new serving area are extended and obviously this can be source of interferences that can drop a call. peaks of RMS_TA_MAX should be noticed on these cells on those particular days;
cdlt;
Lemaure29th June 2013 at 20:36 #69104pixGuesthi,
if i understood correctly, the drops remain AFTER the site is up (tch avail = 100%).
If you do a lock/unlock of BTS, do the drops disappear ?
If you do a full restart of the BTS/Abis, do the drops disappear ?
If you recreate the BTS/cells from scratch in the OMCR, does the drop disappear ?
There is no “good” reason why the cells remain degraded. I can only suspect a hanging sw somewhere.
By the way, what are the CAUSE of the drops ? Radio ? HO ? remote TC ? BSS Internal ?
Regards,
pix6th July 2013 at 05:03 #69105RicardoGuestHi, Sorry Guys I was away.
Dear Pix, Below are Answers to your Queries– Yes you are right, dip in RTCH avail appeared (due to power or Transmission etc ) and after the avail is restored 100% we have degradation, Note that after the site is UP, some time only 01 cell out of 03 will be impacted, sometime site itself will be OK after it is UP but front facing neigbor will be impacted.
We have done all actions listed by you, Lock/unlock BTS, BTS restart, power OFF/ON,Abis change, delete recreate, change HW, change SUMX tried some diff BCCH & MAL List.
Drops are only Radio + handover. BSS & RTC drops are zero
7th July 2013 at 14:50 #69106RicardoGuestWaitng for feedback Gurus
9th July 2013 at 15:22 #69107pixGuesthi,
this is a very weird issue, i’m afraid i can’t help here… you need someone to investigate this issue , but that’s going to be very difficult.
Do you see an increase or decrease of SDCCH traffic ? RACH Attenmpts ? TCH traffic ?
regards
10th July 2013 at 08:43 #69108RicardoGuestHi Pix,
Goo Day! everything is Normal and (SD trffic tch tarffic, rach attempts etc & trend is same ) only thing is increaded Radio drops & HO drops. Also the problem is that which team should investigate/ As per BSSC everything is fine & they have done all possible actions! same nothign could be found from radio side till now
18th July 2013 at 19:31 #69109pixGuestmaybe reset the BSC board ?
it would be good to start a BTS/BSC interna trace and see what is exactly triggering the drops. I don’t know which team can do that ?
Regards
pix -
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