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High Random Access Failure rate

Viewing 15 posts - 1 through 15 (of 20 total)
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  • #50093 Reply
    flavio
    Guest

    does anybody knows if this formulae is correct? It concerns Ericsson equipment/counters.
    [RA Failure] = RAACCFA/(CNROCNT+RAACCFA)
    If so, what are the reasons that can lead a n/w to present bad performance, about 18-20% of failure rate?
    It is present of Ericsson and Siemens nets.

    #50094 Reply
    flavio
    Guest

    additionally, does it imply on any kind of bad end-user perception? which ones?

    #50095 Reply
    pix
    Guest

    flavio,

    can you write down the counters definitions (trigger messages ?)

    #50096 Reply
    flavio
    Guest

    sorry but i don´t have anything but the formulae. i´ll try to find related document from the vendor.

    #50097 Reply
    Water
    Guest

    Hey guys!
    The counters definitions are as follows:
    RAACCFA:- this is incremented every time there is a failure in random access

    CNROCNT:- this counter is incremented for all random access attemtps, failed or successful.

    We have the same problem, there are some of our cells that register as low as 20% of random access success.

    #50098 Reply
    rala
    Guest

    Dear all,

    How to see the random access fail in Alcatel network?

    Thank you in acvance. 🙂

    #50099 Reply
    pix
    Guest

    random access fail is counted as a SDCCH ASSIGNMENT UNSUCCESS (sdnaur)

    in alcatel, the unsuccess varies between 5% and 20% in terrestrial-ABIS BTS, and it is about 50% for satellite ABIS BTS. Those are normal values.

    Regards,
    pix

    #50100 Reply
    rala
    Guest

    Dear Pix,

    a SDCCH ASSIGNMENT UNSUCCESS(sdnaur)is the counter or indicator in Alcatel?
    I cannot search from the Alcatel customer doc.

    or is it the formular?

    Regards,

    #50101 Reply
    pix
    Guest

    Rala,
    open RNO, go to QOS INDICATORS, in the family SDCCH ASSIGN, subfamily UNSUCCESS CAUSES. You will find it here.

    It is an indicator.

    The SDNAUR is the correct name :
    SDCCH_assign_unsuccess_rate ( SDNAUR )
    formula :
    ( ( [MC04] + ( [MC148 – MC01 – MC02 – MC149] + [MC149])) / [MC04 + MC148])

    #50102 Reply
    rala
    Guest

    Oh, I see..
    It’s the SDCCH access failures, right?

    Regards,

    #50103 Reply
    pix
    Guest

    hooo, that’s a rookie mistake :

    failure = radio failures + BSS failures
    unsuccess = congestion rejects + radio failures + BSS failures

    #50104 Reply
    flavio
    Guest

    5-20% are normal values for GSM, or it is vendor related? I checked Nokia performance and it is lower than 1%.

    #50105 Reply
    pix
    Guest

    flavio,

    it has nothing to do with the equipment performances. it has only to do with “how is computed this indicator ?”
    Alcatel is taking into account ghost RACH, while I assume Nokia isn’t.

    Using the same QOS counters, the values should be quite close.

    Regards,
    Pix

    #50106 Reply
    Prakash
    Guest

    Can any one give the formula for Access failure rate (CDMA)formula for Lucent and ZTE.

    #50107 Reply
    vinod
    Guest

    what is the reasons for RACH FAILURE in gsm

Viewing 15 posts - 1 through 15 (of 20 total)
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