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Cell face high SD fail after LAC cutover

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  • #57982 Reply

    Can anyone help me reduce number of sd fail ? if retune parameter needed What’s parameter reference?
    * BSS Alcatel B9

    #57983 Reply

    What is the cause of SD Fail ?
    Radio, BSS or congestion ?

    What is the rate of failure ?

    Number of success ?
    Number of Request ?

    (check the family “SDCCH Assigment” in RNO/NPO)

    #57984 Reply

    Hi ,Pix
    thanks for reply,

    – SD fail caused of radio number = 1544
    without failure caused of BSS and Block

    – Before cutover failure rate= 2%
    After cutover failure rate= 10%

    – Number of Request=26761
    – Number of success=25217

    #57985 Reply


    when i do the calculation 1500/26000 = 5.8%, not 10%

    so there is a mistake somewhere in your numbers ๐Ÿ™‚

    anyway, so let’s just say that after you redesign your LAC borders, the SDCCH ass fail radio rate have increased, but is still within acceptable range.

    do you also notice an increase in SDCCH requests ? in SDCH duration average ? what about the Location update ratio ? I guess it also increased, if that cell is at the lac border?

    DO you notice increase in SDCCH drop rate as well ?

    Try to give me a complete picture of what changed in terms of QoS indicators after the cutover.

    Once you answer, I might ask even more indicators ๐Ÿ™‚

    Sorry to ask to many details… IMO though, the sd fail is still OK ๐Ÿ™‚ But never mind, we can continue the investigation.

    #57986 Reply

    Yes , you’r right pix it ‘s just 5.8 % not 10% .
    I found something increase like you said :
    – SD Drop Rate increase from 1 % to 3%
    – SD duration average is retain
    – SD request of LU update is increase from 17% to 66%
    Now I ‘m tring to improve CSSR because after cutover CSSR fall down from 98 % to 88%
    :)How can I do ,Pix
    #Um retune freq. I ‘ve done many times but failure did not change at all

    #57987 Reply


    1/ Could you try to increase the Cell Reselect Hysteresis in both cells ? Also, increase the HO_Margin in both directions.

    2/ Could you relocate (and add) the SDCCH timeslot onto other TRX’s ?

    3/ Could you resize the size of the RSL on the Abis for the TRE that are carrying SDCCH timeslots ? I mean.. instead of multiplexing 4 RSL in 1 Abis TS, try to multiplex only 2 RSL / Abis TS.

    Could you give me the RTCH_Assign_Fail_Radio_Rate and *_BSS_Rate and *_Cong_Rate ?

    Do you see an increase in the amount of RTCH_Assign_Request ?


Viewing 6 posts - 1 through 6 (of 6 total)
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