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Cell face high SD fail after LAC cutover

Viewing 6 posts - 1 through 6 (of 6 total)
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  • 15th July 2009 at 10:08 #57982
    Phantom
    Guest

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

    15th July 2009 at 12:01 #57983
    Pix
    Guest

    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)

    16th July 2009 at 03:53 #57984
    Phantom
    Guest

    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

    16th July 2009 at 06:22 #57985
    Pix
    Guest

    Hello,

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

    so there is a mistake somewhere in your numbers 🙂

    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 🙂

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

    16th July 2009 at 10:40 #57986
    Phantom
    Guest

    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

    16th July 2009 at 17:20 #57987
    Pix
    Guest

    Thanks.

    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 ?

    Cheers,
    Pix

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