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GPRS_UL_TBF_Establishment_Fail

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  • #49747 Reply
    Neno
    Guest

    dear all
    first good avter noon, i need your help as i have i problem in GPRS_UL_TBF_Establishment_Fail

    B. Regards

    #49748 Reply
    pix
    Guest

    it sounds like you’re working with alcatel ?

    reset the cell(s), then reset the GPU, and check your GPU usage : you might need an extension of GPU’s. Check also your current NSS and BSS release, there might be some new releases that fix this kind of issues.

    (FYI, gprs ul estab fail is a typical alcatel B8 problem, so don’t hesitate to raise this issue to your vendor’s interface)

    #49749 Reply
    Neno
    Guest

    thanks PIX
    please i need more deatails about this problem, since we are using alcatel B8.
    please if you dont mind i need tour email

    #49750 Reply
    pix
    Guest

    please, contact your TPM, he’ll guide you through this…

    #49751 Reply
    NarChai
    Guest

    Hi friend
    If GPRS_UL_TBF_Establishment_Fail only UL but DL is normal and most of failure come from RF and there no HW fault(TRE).
    I recommend you check cell parameter “GAMMA_TNx=0” or not? if not correct them.

    #49752 Reply
    TNS
    Guest

    Hi all,
    I’m agree wiht NarChai…
    If you will check the Gamma parameter, take a look to the Alpha parameter too…
    Good look

    #49753 Reply
    Neno
    Guest

    hello NarChai
    why GAMMA_TNx should be equal to zero, waht do you think about that PIX

    #49754 Reply
    pix
    Guest

    gamma = 0 means you disable UL PC for GPRS (note : this doesn’t disable UL PC for GSM 🙂 )

    it is correct that UL PC for GPRS can have a negative impact on UL establishment sometimes (bugs in MS ? bugs in software ?). Try to put it to zero, and see if it helps.

    Pix

    #49755 Reply
    Neno
    Guest

    Hi PIX
    if we put it 20 what is that mean

    B.R.

    #49756 Reply
    pix
    Guest

    it’s complicated, i don’t have time to explain… if you put 20, it means you have UL PC for GPRS = enable, but with a quite safe value (30 is default, but a bit aggressive)

    try 0, my friend…

    pix

    #49757 Reply
    Neno
    Guest

    Dear Pix

    iam sory if i am wasting your time but realy i trust in your answers

    #49758 Reply
    pix
    Guest

    you’re not wasting my time, it’s just that I don’t have the time 🙂

    i’ll just give you the formula by memory…

    tx power of the next burst (i.e. timeslot) :
    UL TX POWER = GAMMA – ALPHA*(DL RXLEV + 48)

    This is a linear equation, i’ll let you do the excel macro and try different values. If you have questions, don’t hesitate.

    Pix

    #49759 Reply
    NarChai
    Guest

    Hi neno

    How about your problem? i has problem in my network same you and i solve that i recommend you. i not sure about this parameter.
    So PIX can explain you better me.

    I just share!

    #49760 Reply
    pix
    Guest

    narchai,

    have you tried turning it back on ? the same thing happened to me, ul estab = terrible for many cells. It started this way :

    I enabled the PC UL GPRS. Everything worked fine for a while. Then suddenly the UL estab decreased terribly. As a troubleshooting procedure, UL PC was deactivated, and that solved the problem !
    I think i re-enabled it for test trial, and it worked fine also… very weird. It might be due to some MS not supporting UL GPRS PC (??).

    Pix.

    #49761 Reply
    Yogesh singh
    Guest

    Hi,
    Pls try the following values of Parameters:
    1.GAMMA=0,ALPHA=0,
    ALPHA is sent from the BSC to the MS and decides the level of reduction of the MS output power in relation to the path loss. The values are given as a multiple of 10, i.e. the value 5 means the reduction level of 0.5.
    GAMMA is sent from the BSC to the MS to give a target value for the
    received signal strength at the BTS. The GPRS have no dynamic power regulation. So if the GAMMA is set to 0dB the MS will send max power when sending data on the PDCH. GAMMA =16dB gives that the MS will always send (max power – 16dB) on the PDCH. So if the GAMMA = 16dB in some area in some cells the BSC will not hear the MS when the MS have been given a PDCH to send on.
    2.Check for PDCHPREEMPT:Default is 0 can be set to 2 depending on CS Traffic, so that only idle ondemand PDCHs will be preempted.
    3.Put TBFULLIMIT=1,default is 2

    Rgds
    Yogesh

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