- This topic has 154 replies, 1 voice, and was last updated 13 years, 9 months ago by pix.
14th July 2007 at 10:24 #35598MackGuest
Can any suggest me how can i overcome from the prolem of sd drop and tch drop in my network15th July 2007 at 18:15 #35599PixGuest
First of all :
Make a clean frequency planning (with hopping for instance)
Set all your parameters at default value, as recommended by your vendor.
Regards,17th July 2007 at 03:11 #35600GPAGuest
Good am. how can i determine that im currently encountering an SD drop? thanks17th July 2007 at 06:15 #35601PixGuest
The most reliable way is to check your QoS indicators. SDCCH drop is a very common indicator among all vendors.
or if you’re just doing a drive test, you’ll have to check the layer 3 messages. If there’s a stop in the sending and receiving of the SDCCH messages (authentication, ciphering, etc…), then you can assume it is a SDCCH drop.18th July 2007 at 13:25 #35602raviGuest
hi all !
Pls tell what is the measurement period for SDCCH : 480 ms or 2*480 ms ?18th July 2007 at 14:46 #35603PixGuest
the measurement period for a SDCCH is neither of your choice…
it is 470.2 ms !
(102 TDMA frames)
For TCH, it is 480ms (104 TDMA)
Just to be clear, the SACCH multiframe period = the measurement period (either 470.2 or 480ms)
Regards,20th July 2007 at 07:21 #35604raviGuest
u mean to say that SACCH measurement time = SDCCH measurement time = 470.2 or 480 ms .
But I read somewhere that for 2 SDCCH block we have one SACCH block…..????
Also pls tell how 470.2=480 ms….??
Also , I have a very strong doubt about the mapping of E1 channels …. I have posted a new topic with the same heading on 18 july ….. ….. Can u pls have a look20th July 2007 at 18:16 #35605LudwingGuest
I would like to know how to dimensionate SDCCH, should I use a formula, which one?21st July 2007 at 18:36 #35606SPBGuest
Why is MSC pagging success rate is low in the morning hour between lets say 3-8am…no change in parameters in BSC or cell level? no frequency retune..practically no change was made.what are the things we should check in this case..no extra surplus of traffic and no SDCCH congestion and again it happens in morning hour?
The problem started happening recently..
GSM 1900-Ericsson BSC/BTS and Nortel MSC.
Thanks23rd July 2007 at 06:00 #35607krGuest
during location update , the MS sends its old LAC and TMSI to the BSC . If somehow TMSI is not recongnizable then MS is asked for the IMSI no.
My question is why doesn’t the MS sends IMSI first time only ? Why does it send the TMSI first?
thanks in advance24th July 2007 at 03:56 #35608IgOEnGuest
As long as I know, IMSI is restricted to send in Air Interface (please CMIIW). So if the MS is still on the same LAC and CI, the MSC will only sent TMSI which is the encryption from the IMSI. IMSI will send if the New VLR doesn’t know where is the Old LAC/CI because there are not in their dbase (EXTERNAL LAC).
IMHO perhaps your decreament in Paging Success Rate because the subscriber had turned down their MS in that time, so there are no paging response from the MS.24th July 2007 at 04:14 #35609SPBGuest
Please elaborate some of the abbreviation…i think i got the idea you are mentioning. One more thing i forgot to mentioned was there was couple of new LACs created few wks back in rural areas for roaming purpose for another carrier with handful of sites in one LAC as they are in different BSC and different geographical areas of the network. If you could please provide some starting point..
Thanks again.24th July 2007 at 05:06 #35610IgoenGuest
I am little bit confused with your problems. Perhaps you can tell me the problems in order of action you have done.
Which LAC has been going down for the paging success rate? Is that the New LAC/BSC that you have mentioned before or the other LACs because of the appearing of New LAC?
If your mention is your paging (total) is going down after splitting LAC/BSC, it perhaps you have unsyncron dbase between MSC-BSC(specially New BSC/LAC) Please check the BSC SPC and LAC dbase from the MSC.
But if your mention is your New LAC/BSC’s paging going down, it perhaps because of the transmission. Usually in rural area, the transmission is going flicker in that time (3-8AM), perhaps because of bad weather.
Paging success rate can be rise by setting the paging timer in the MSC
regards,24th July 2007 at 05:41 #35611SPBGuest
I am sorry i made you little confuse here. The mainly the problem is overall MSC paging success rate went down (anywhere from 89% to 79%). And this is happening only in the morning hours. I will start cross checking the dBase between the BSC and MSC.Also, previously you mentioned about IMHO…
Thank you24th July 2007 at 06:10 #35612IgoenGuest
IMHO = In My Humble Opinion 🙂
Sorry bout the abbreviation