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Extended UL TBF Mode

  • This topic has 10 replies, 1 voice, and was last updated 3 weeks, 1 day ago by Arthurbleaw.
Viewing 11 posts - 1 through 11 (of 11 total)
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  • #66662 Reply
    ghamiz
    Guest

    we have recently activated Extended ul tbf mode in our nokia network? all kpis including tbf establishment success rate, tbf success rate and throughput are degraded…

    my major concerns are
    1. enormous increase in signalling messages in UL direction
    2. count of tbf establishment failures are constant while the tbf establishment attempts and success have reduced, this is affecting the KPIs…

    :S

    how to sort the problem fixed???

    #66663 Reply
    pix
    Guest

    hi ghamiz,

    the TBF are now lasting a longer time. Their lifetime is increased !
    Therefore :
    1/ during the time the TBF is “extended”, there is UL blocks which are sent during this extension. They are seen as signalling. This is not a problem. You can slow the frequency of those signalling messages (t_extended_ul_poling, or something like this)
    2/ the number of tbf establishments is reduced because the same TBF is reused ! So over 10 seconds, instead of using 5 TBF, the MS will use only 1 TBF. But the probability of TBF drop over those 10 seconds is the same as before πŸ˜‰

    Extended UL is a feature that leads to GOOD quality from subscriber point of view, but “worst” Kpi.
    So, it is up to you to explain that to your management. If they want to strictly stick to KPI monitoring, without taking into account the subscriber perception, then disable this feature…

    Pix
    Regards

    #66664 Reply
    Cheb
    Guest

    Hi ghamiz,
    Which type of pcu cards installed in BSC?
    For PCU2_D check ZWOI:46;
    00113 POLLING_INTERVAL_BG_LOW 0004 YES
    00114 POLLING_INTERVAL_IA_LOW 0001 YES
    00115 POLLING_INTERVAL_ST_LOW 0001 YES
    00086 POLLING_INTERVAL_IA 000A YES
    00087 POLLING_INTERVAL_BG 0004 YES

    #66665 Reply
    ghamiz
    Guest

    hi cheb,
    we have PCU 2D card and RG10 and parameters set to optimised value as recommended by NSN. after activation of the feature the signalling has increased four times, the number of tbf establishment attempts (and thus success) have been reduced but the tbf establishment failures are constant. Thus tbf setup success rate and tbf success rate both have degraded :S

    :,(

    #66666 Reply
    ghamiz
    Guest

    pix…

    thanks for your detailed response…you are the man :))

    #66667 Reply
    pix
    Guest

    ghamiz,

    you’re welcome πŸ™‚

    #66668 Reply
    dElT@
    Guest

    hey pix,
    c@n I get @ bit more info on thi$?
    i me@n in the extended mode the MS is polled lesser th@n usu@l so howcome the $ign@lling i$ incre@sed? @nd also what are these mess@ges on UL th@t @re seen @s sign@lling?

    πŸ™‚ sorry for two m@ny question$ πŸ˜›

    #66669 Reply
    Rex
    Guest

    Hi ghamiz,
    in order to prove to the management that extended UL tbf is good, do the measurement like ping, RTT will decrease and you’ll see improvement.
    Regards,
    Rex

    #66670 Reply
    pix
    Guest

    Deit,

    you are using a n00b keybo@rd, please get rid of it !

    during extended mode, the MS is artificially kept active, and during this time, only signalling are exchanged between both parties.
    1/ BTS sends USF to the MS, and once in a while (in improved extended mode) will send a PDAN with polling indication (I think it’s a PDAN packet dl ack/nack, but not sure anymore… it’s a DL msg anyway)
    The Ms replies with an UL packet “dummy block”, which is counted as signalling.

    When the MS is in a real UL transfer, the BTS sends USF in DL (it’s not a message, it’s just a flag in a DL PDTCH), and the MS will send REAL data in UL. So there is not much signalling involved here.

    Rex >> Yes, good info πŸ™‚

    regards
    pix

    #66671 Reply
    ghamiz
    Guest

    thanks Rex,
    yes the ping and RTT have REALLY improved, our primary purpose of activation of this feature was the same πŸ™‚

    #66672 Reply
    rahul
    Guest

    what is extended ul tbf mode.

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