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SDCCH blocking is high

Viewing 15 posts - 16 through 30 (of 62 total)
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  • #45815 Reply
    Dirty
    Guest

    Hi, is there any recommended value for T3212 timer in the network (the timer used for location updating). what are the effects of increasing or decreasing the T3212 timre on the paging performance for a LAC.

    #45816 Reply
    Pix
    Guest

    Hi Dirty,

    T3212 = 4 hours (default)
    every 4 hours, a mobile will send a location update message to its BSS, using a SDCCH subchannel for 3 seconds ๐Ÿ™‚

    increase T3212 : instead of every 4 hours, maybe do every 6 hours.
    It reduces the amount of location updates in your network, reducing the SDCCH load (and TCU load as well)
    drawback : there is a timer in the NSS that can expire. If the NSS receives a LU before the expiry, then the timer is restarted. Otherwise, the mobile becomes “IMSI DETACH”-ed. So ensure that your NSS timer is well defined.
    There must be another drawback, but I can’t remember…

    Decrease T3212 : instead of 4 hours, do 2 hours. That will double the amount of periodic LU in your network, overloading TCUs and SDCCHs.

    Regards,

    #45817 Reply
    Da Architect
    Guest

    Hello Pix:
    You said that there is a timer in the NSS that can expire. If the NSS receives a LU before the expiry, then the timer is restarted. Otherwise, the mobile becomes “IMSI DETACH”-ed. So ensure that your NSS timer is well defined.

    Please, I urge to know more details about this timer. I have a problem of Paging Failure, and it might be due to this NSS timer!

    #45818 Reply
    Pix
    Guest

    Hello Da Architect,

    If you urge so badly, I’d rather tell you now then ๐Ÿ™‚

    Ok, i’ve been looking for the name of the parameter for 30 minutes now. And I just can’t find it ! NSS is so obscure, it is scary.

    However the 3GPP doc confirms what I said earlier :

    “2.4.2 Implicit IMSI detach
    Implicit IMSI detach operation is the action taken by the VLR to mark an MS as detached when there has been no successful contact between the MS and the network for a time determined by the implicit detach timer. The value of the implicit detach timer is derived from the periodic location updating timer. During an established radio contact, the implicit detach timer shall be prevented from triggering implicit detach. At the release of the radio connection, the implicit detach timer shall be reset and restarted. Implicit IMSI detach shall also be performed in the case of a negative response to an IMEI check.”

    (ref : Location registration procedures
    (GSM 03.12 version 7.0.0 Release 1998)

    I’m sorry, I really can’t find its name. But if you find it, PLEASE share it with me ๐Ÿ™‚

    Regards,

    #45819 Reply
    Tomar
    Guest

    Hi all,
    May be one note to increase T3212: instead of every 4 hours, maybe do every 8 hours.
    It reduces the amount of location updates in your network, reducing the SDCCH load. Yes it is true, but only during the night โ€“ nobody send/receive SMS nobody makes MTS/MOC call.
    During the day/BH, is the saving of resources nearly zero. Because every make a call or SMS โ€“ The timer is restarted in the mobile, but also in NSS. If the NSS receives a LU before the expiry, then the timer is restarted.
    If the timer in the NSS expired, than NSS will try to page this MS. Than the mobile becomes “IMSI DETACH”-ed.
    But it depends on behaviors of your customers.
    BR
    Tomar

    #45820 Reply
    nitin
    Guest

    Plz tell me the reason for high sdcch blocking in showcase even if traffic is less?

    #45821 Reply
    vikas kanwar
    Guest

    wrong t3212 timer settings for few cells in BSC ( timer value is lower than other cells so more periodic location updates by MSs resulting high signalling load resulting HIGH SDCCH LOAD

    #45822 Reply
    Gerald
    Guest

    I am having problems with our network on SDCCH. Two sites are having low SDCCH accessiblity and the company has a threshold of 97%.
    please can you tell me what are the possible cause for this drop

    #45823 Reply
    Gerald
    Guest

    please can somebody help me. i am really waiting for your utmost attention……….

    Please help

    #45824 Reply
    bob
    Guest

    Gerald can you post the formula you using

    #45825 Reply
    Gerald
    Guest

    SDCCH accessibility =

    Assigned successful SDCCH/(Assigned attained SDCCH – Assigned number of SDCCH seized)

    #45826 Reply
    nitin
    Guest

    hi
    plz tell me if utilization is high will it lead to SD blocking.some of my cells have utilization above 200% but no SD Blocking n few with 150% have SD blocking up to 25% even if SD available is same for both case.

    #45827 Reply
    rama narayan nanda
    Guest

    can anyone plz tell me what is the reason for sdcch block

    #45828 Reply
    Pix
    Guest

    The answer is in this post, keep looking. It’s a bit in the past.

    #45829 Reply
    Anit
    Guest

    Can anyone help me to tackle the problem of High RACH Collision counts.Please give me the reasons and suggestions for the same.

    BR
    Anit Saxena,
    Bangalore,India

Viewing 15 posts - 16 through 30 (of 62 total)
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