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Drops BSS due to transcoder

Viewing 13 posts - 1 through 13 (of 13 total)
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  • 23rd March 2009 at 08:31 #56375
    ATTO
    Guest

    Hi All,

    I face problem of drops BSS due to remote transcoder ( Alcatel vendor )on one TRX in a cell ( the cell config is 2 TRX).
    This is the result i’ve got:

    TRX1: DRops_BSS_TC= 0;
    TRX2: Drops_BSS_TC= 60%;

    I have changed the TRX, cable TX-RX , combiner but nothing.

    There is no alarm at OMC center and everything looks clear.

    PS: All other stats on the 2nd TRX looks great:

    TRX2: call success rate = 98%
    TRX2: Incomming Handover efficiency = 97%

    Any idea ?? I really need your help .

    Thanks in advance.

    23rd March 2009 at 13:50 #56376
    Rex
    Guest

    Hi ATTO,
    Is AMR activated? If Yes, check that TC supports it (NSS). Could be Abis pb (BER, FRAME_ALIGNMENT etc), TRX pb (you said that is OK).
    Regards,
    Rex

    23rd March 2009 at 13:51 #56377
    Rex
    Guest

    I forgot, if not all these try to reset corresponding TCU.

    23rd March 2009 at 14:17 #56378
    ATTO
    Guest

    Hii Rex,

    Thanks for your quick response.

    Below my answers/ eventhough questions:

    Is AMR activated?
    No. AMR is not activated on BSS part.

    Could be Abis pb (BER, FRAME_ALIGNMENT etc): Is there possible to have high BER only on one TRX ( of course i know that this TRX is not faulty and the cell have 2 TRX defined)?

    What about frame alignment/Misalignment?? I mean could frame be misaligned for days even when i changed hardwares?

    I will try to reset the corresponding TCU .

    Thanks

    23rd March 2009 at 18:47 #56379
    Pix
    Guest

    If it’s not the TRX, then it’s either the ANC or the SUM board.
    If it’s not them, then it’s the BTS cabinet itself 🙂 It’s extremely rare though…

    Try placing the TRX board into another slot of the cabinet ?

    And finally, try re-creating the cell / BTS from scratch in the OMC-R.

    You’re right, an ABIS issue would impact all TRX in the cabinet. Only an Abis misconfiguration could explain this… but is it possible to misconfigure the Abis ? Perhaps a VSAT ?

    Regards
    pix

    23rd March 2009 at 19:21 #56380
    Rex
    Guest

    Hi,
    No, Abis pb cannot have impact only in one TRX nor in one cell. It’ll have impact in all cells of the BTS. Sorry for my mistake!

    24th March 2009 at 14:24 #56381
    ATTO
    Guest

    Hi

    Rex,

    I reset the TCU but nothing.

    Pix,

    Even the ANC have been changed, not only TRX.
    I will try the other actions that U suggest.

    Thanks.

    24th March 2009 at 15:37 #56382
    Pix
    Guest

    Atto,

    I’m not a hardware expert, so I’m just giving ideas. I’m not sure it’s going to work… If it doesn’t, I’m afraid you’ll have to contact your TAC support…

    1st April 2009 at 07:25 #56383
    TNS
    Guest

    Hi, ATTO.

    What is the name of the indicator at TRX level…?

    In my experience i have drops due to remote TC due to 2 reasons:

    transmission interruption – all cell on the same abis affected.

    TC board failure – many cell affected.

    But never only one TRX.

    What is the traffic carried by TRX1 and TRX2? ( Is TRX1 loaded at all? ).

    BR,

    3rd April 2009 at 11:26 #56384
    ATTO
    Guest

    Hi TNS,

    The name of the KPI is RTCH_drop_BSS_transcoder_rate (on trx level). The incremented counter is MC739 at TRX level.
    I put high priority of traffic on TRX1 in order to reduce drops. But the cell is loaded this is why TRX2 got traffic.
    The problem began after a dissociation issue. 2 BTS sharing the same E1.
    It is really weird because the TRX impacted have same TCUC board as another TRX which is not impacted.

    Do U think that timeslots on E1 ( the impacted TRX have 2 mapped timeslots on the E1) could be faulty without any alarm or any other disturbance ? Because this TRX have also defined SDCCH and there is no SD drop or SD assignment failure.

    Thanks!

    5th April 2009 at 20:58 #56385
    Rex
    Guest

    Hi ATTO,
    on Abis level try to remove 1 TRX, declare the sector with 1 TRX, reset OMU and then add again the second TRX.

    5th April 2009 at 21:00 #56386
    Rex
    Guest

    What multiplexing scheme you’re using for that BTS?

    6th April 2009 at 16:42 #56387
    ATTO
    Guest

    Hi Rex,

    I ‘ll try the actions suggested and the multiplexing scheme is 64 Kb/s statistic.

    thanks!

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