- This topic has 23 replies, 1 voice, and was last updated 3 years, 7 months ago by Wallis Dudhnath.
1st September 2005 at 09:55 #42076NyasakingGuest
does anybody know the average call setup time in GSM?4th November 2005 at 11:35 #42077Garry !!Guest
On an average it is approx 3.5 to 4 sec, but a higher value has to be thoroughly investigated and is definately a source of problem.
Garry !!6th November 2005 at 09:36 #42078paryGuest
what is the drop related to MS message (error in connection). is it SDCCH drop or RACH drop OR AGCH drop or NOT.
BR7th November 2005 at 10:02 #42079Garry !!Guest
Well, MS message (error_in_connection) is generated by MSC rejecting your CM_SER_REQ message. It is internal and cannot be construed as RACH drop as RACH access is done by that time. Secondly its not even AGCH drop because the MS has not allowed Access_grant.
This problem is caused by some problem in the PCM trunks towards the MSC. Majorly it is solved by troubleshooting these PCM trunks.
Garry !!7th November 2005 at 11:32 #42080paryGuest
Thanks carry for your valuable clarification:
Further more we till facing this problem in our net work(error in connection).& we already perform some investigation: such like Redimensioning the Air interface,new roubst plan for our freq,optimization for LA,BTSs config, …..& so on(all major in our side (radio planning)).
So I think you are right, Cuz we have two link system, PDH & LMDS as backbone & our TX planners are quite new in LMDS technology.
But regarding the troubleshooting, what is the efficient way to trace it,is it recommisioning our links(& what Abis or Ater) or it related with MSC performance or what…. Plz i need more clarification on it(Document if available).
OUR VENDOR IS ALCATEL
thanks7th November 2005 at 13:24 #42081Garry !!Guest
This error is not generated by BSS, so you need not re-do your freq plans. LAC optimization/BTS reconfig would not solve this problem.
Try troubleshooting PCM trunks, probably mapping of the TSs. The best way to start is from the MSC end, I assume this problem is network wide rather than cell specific. Check whether some new recently added PCM. I would suggest start from A-inf then A-ter and then A-bis..This would reduce the time in troubleshooting.
Unfortunately my friend, there are no documents available for such errors, as they are network specific. All I have is good years of experience from which I can judge the situation.
Garry !!8th November 2005 at 12:50 #42082Garry !!Guest
Do you have any alarms in the areas having “error_in_connection” ?
Garry !!16th November 2005 at 10:10 #42083waterGuest
we are having some problems in our network. when you try call a number, the phone displays a message”call failed, Not available.” we have no idea what is not available. but if you try again you go thru.
please help me find out what cud be the cause of this problem. we are using ericsson equipment.16th November 2005 at 13:34 #42084Garry !!Guest
Well, there are different causes to such messages. Firstly let me know following things..
1.Is it a cell or site or bsc or msc or network related problem ?
2.Do you get a display on your mobile phone of “call failed” or Do you get a message “The subscriber is not reachable” ?
3.Is the message “call failed” is just on the screen when you press the call button ?
4.Have you done the drivetest in that area ? what are the observations from l3 point of view ?
Let me know your comments.
Garry !!17th November 2005 at 05:51 #42085sanjGuest
i m new to gsm pls help me. suposse we have 3TRX in one cell. how BCCH, SDCCH &TCH will be mapped in TS of three TRX?
Please explain with some examples.Thanks in advance.17th November 2005 at 06:22 #42086joodGuest
1)combined mode(light load signaling)
BCCH on TS0 contained 4 subchannel.
SDCCH on TS0 contained 4 subchannel.
7 TCH on the remaining 7 TSs on TRX1 & the whole 16 TSs on TRX2 & TRX3.
2)Not combined mode(heavy load signaling)
BCCH on TS0 contained 4 subchannel.
SDCCH on TS1 contained 8 subchannel.
TCH on tha remaining 6 TSs & 16 TSs on (TRX2 , TRX3).
## Further more you can add more SDCCH if your signaling is still heavy.17th November 2005 at 11:22 #42087Garry !!Guest
Hi Sanj & Hi Jood,
Jood is right with his examples, do let me know if you have some more specific queries.
Garry !!18th November 2005 at 11:30 #42088sanjGuest
thanks for your wonderful explaination. it was really nice. i hope u continue this way on this forum. incase if u dont intend so then pls give me ur personal email id….if dont mind so that i can ask for help in future.
thanks again.bye5th December 2005 at 11:53 #42089waterGuest
The problem in network wide. when you try call the number, pressin the call butto, it tries to set the call up, then after around 5 sec the message displays on the Mobile “call failed not available” of just “call failed”
we do drive tests every two weeks in the cities and the major villages, but we cant exactly pinpoint what cud be the cause of this problem. we don understand exactly where (in the system: BSS or Corenetwork) it happens.
help7th February 2011 at 08:06 #42090nuxGuest
i also have some problem on call setup. for information, i get one cell re-homed from old BSC to new BSC. when i tried to make originating call, network could “ring” the opposite subscriber (so i think ISUP message has been received) but a few moments later it was disconnected with display in mobile “network unavailble”.
i’m in charge at core network, can anybody tell me what alarm it is?