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Call Setup time in GSM

Viewing 15 posts - 1 through 15 (of 24 total)
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  • #42076 Reply
    Nyasaking
    Guest

    does anybody know the average call setup time in GSM?

    #42077 Reply
    Garry !!
    Guest

    Hi,

    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.

    Best regards,

    Garry !!

    #42078 Reply
    pary
    Guest

    hi all
    what is the drop related to MS message (error in connection). is it SDCCH drop or RACH drop OR AGCH drop or NOT.
    BR

    #42079 Reply
    Garry !!
    Guest

    Hi Pary,

    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.

    Best regards,

    Garry !!

    #42080 Reply
    pary
    Guest

    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
    thanks

    #42081 Reply
    Garry !!
    Guest

    Hai Pary,

    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.

    Best regards,

    Garry !!

    #42082 Reply
    Garry !!
    Guest

    Hi Pary,

    Do you have any alarms in the areas having “error_in_connection” ?

    Best regards,

    Garry !!

    #42083 Reply
    water
    Guest

    hey guys!!!
    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.

    #42084 Reply
    Garry !!
    Guest

    Hi Water,

    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.

    Best regards,

    Garry !!

    #42085 Reply
    sanj
    Guest

    hi garry,

    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.

    #42086 Reply
    jood
    Guest

    Hi sanj
    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.

    #42087 Reply
    Garry !!
    Guest

    Hi Sanj & Hi Jood,

    Jood is right with his examples, do let me know if you have some more specific queries.

    Best regards,

    Garry !!

    #42088 Reply
    sanj
    Guest

    hi garry,

    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.bye

    #42089 Reply
    water
    Guest

    hey Garry!!!

    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.

    help

    #42090 Reply
    nux
    Guest

    hi all,

    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?

Viewing 15 posts - 1 through 15 (of 24 total)
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