- This topic has 8 replies, 1 voice, and was last updated 12 years ago by korgi.
26th May 2010 at 14:16 #62879JBGuest
I have been dealing with this high SDCCH drops for quite some time and need to resolve this issue. The SDCCH drops is 16.5% for the whole system and this has been going on for more than 2 years. Please help.
My cell re-selection Hysteresis value is 6. What else can I check? Please help.26th May 2010 at 16:09 #62880PAulGuest
Is the site at the border of LAC/BSC?
If yes, then you need to try to change the re-selection Hysterisis.
If not, just check, whether :
1.SDCCH drops happen due to handover or not?
2.Frequency interference-CO-channel or adjacent channel (Check BCCH only if SFH, check also TCH if BBH)
3. THe TRX that brings SDCCH has a hardware failure.
Try to put SDCCH to another TRX.
Paul27th May 2010 at 09:53 #62881xyzGuest
U have enabled sdcch HO??
if so try disabling it.
if no try to remapp the sdcch in the hopping TRX to the BCCH TRX(Non hopping one).
Also try to implement antenna hopping parameter to reduce SDCCH drop.
Also do a cell wise analysis to arrest the hardware issues.
Hope this will help
xyx27th May 2010 at 10:43 #62882BrotherGuest
is it nokia?2nd June 2010 at 08:42 #62883KJBGuest
Kindly check the following.
1- Site/Sector is stable means it should not be fluctuating.
2-TRXs are stable,Not fluctuating or not being restart frequently.
3-DL quality of the Segement/TRXs.(Q5)
if these are degraded then replace TRXs and check VSWR should be good one.
4- Adjust TA value (try to decrease)
5- HYS value can be set 10 if this is Nokia BTS.
Thanks31st July 2010 at 07:58 #62884Huawei – ManGuest
Can ping-pong location update affect to increase of SDCCH Drop?31st July 2010 at 13:07 #62885BrotherGuest
high traffic increases the drops, it is sd or tch traffic,
one simple reason is, if there is a problem (interference,hardware or any minor problem etc.) and there is no traffic it is not visible.2nd August 2010 at 04:25 #62886jaihuGuest
can adjacent channel interference cause an sd drop of 15%? in one case in our network, the cell at border and it has adjacent channel interference both and around 15% sd drop?2nd August 2010 at 11:50 #62887korgiGuest
I dont think that adjacent interference influence the SDCCH drops.
to trigger the HO cell level should be (about) 5-6dbm for a while.
adjacent frequency should be better by 15dbm to influence its adjacent frequency. Hence, they can not affect each other. I mean if one of them is better by 5dbm than other HO occurs.
However, if this frequencies are not defined as a neighbor then they will affect each other.
If my idea is wrong please notice me.