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UL_TBF_drop due to N3103 (ALU B11)

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  • #69121

    Good night, dear GSM experts!
    Good night, dear Alcatel gurus!
    Good night, dear dear Pix!

    Being back to my work, I face a new problem 🙂
    I’ve noticed that there are a lot of cells with abnormally high UL_TBF_drop_rate – more than 25-35%. Mainly all those drops are due to N3103 counter expires (i.e. becomes more than N3103_limit). This case belongs to radio problems, but I can’t find any obvious or reasonable explanation for such situation:
    – there are no problem with coverage
    – no interference (at least significant – to cause such UL_TBF_drop_rate increasing…)
    – all other KPIs are good (either PS or CS)
    – for each cell I can find the date when the problem began. As usual it happens abruptly and without any other symptoms (alarms or other KPIs deterioration)
    I think it’s not a real radio problem because if it’s so we should face both N3103 and N3101 KPIs deterioration, shouldn’t we?
    And my questions:
    1)How do you think, could it be some terminals which act incorrectly when they finish UL TBF?
    2) In our network N3103_LIMIT = 1 and it is according to recommended rules (in OMC-R help).
    What is the danger if we break this rule and set another value for N3103_LIMIT? And which value we should try?

    Many thanks in advance.
    BR, Lily


    Hi Lily !

    Still alive and working hard, I see !

    Could you recap the N3103 mechanism ? Is it the one where the MS does not send the final acknowledgment, which is actually kind of useless anyway ?

    I think it is a good idea to increase the LIMIT, always good to test something.

    I don’t think the MS are at fault though, especially if the degradation starts suddenly and go as high as 30%. If possible try to do a trace (Abis/AterPS)


Viewing 2 posts - 1 through 2 (of 2 total)
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