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SDCCH drop

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  • 18th October 2011 at 07:05 #66974
    pix
    Guest

    Dell,

    Could you explain what is happening when the MS enters the cell in Idle Mode ?

    You say there is a loss of signal, resulting in “no network” ?

    LU REQ -> LU ACCEPT = 17 seconds

    1/ The Loc Upd Req is probably caused by an IMSI ATTACH.

    2/ Such a long duration cannot be caused, to my knowlege, by a “Jammer”. So I would investigate a core network problem – but why only this cell would have this problem ???

    I’ve no other idea.. a jammer creates interference, so during a call you should see a very bad rxqual.

    regards
    pix

    18th October 2011 at 12:20 #66975
    Dell
    Guest

    Hi Pix,
    when MS enters the cell in Idle mode it loses signal (No Service). After that it begins LU request (probably IMSI Attach as you said) and lasts 17 sec till LU accept. I don’t think so there is a jammer nearby, because we don’t have interference in idle measurements, UL quality HO is fine, so, we do not suspect in UL interference. Call drop is low. Sdcch drop, sdcch traffic and sdcch duraiton increased as well as IMSI detach rate. I thought maybe there’s other equipment than jammer such as, let’s say, anti-tapping equipment or something else.
    Regards,
    Dell

    21st October 2011 at 03:03 #66976
    apde
    Guest

    Dell,

    have u try to reconfigure SDCCH?
    if all SDCCH in CHGR 0, u can try to move it to CHGR 1 or u can try to reset TRx within SDCCH inside.

    CMIIW..

    25th October 2011 at 13:30 #66977
    Dell
    Guest

    Hi,
    during measurements we noticed that between LU Req and LU accept there is 4 seconds in cells with Legacy (SSP, RCP) and more than 16 seconds in cells within NGN (Call Server, Media Gateway). Which parameter or timer in NSS should consider in order to solve this.
    Regards,
    Dell

    27th October 2011 at 05:45 #66978
    CBE
    Guest

    Hi all,

    We are maintaining Huawei NodeBs, now we are getting reference clock source abnormal alarms for both ATM and IP medium sites. Please give valuable suggestions to solve the issue.

    Thanks in advance.

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