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Call Drop on SD channel

Viewing 11 posts - 1 through 11 (of 11 total)
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  • 12th February 2011 at 12:18 #65763 Reply
    Johny
    Guest

    Hi Every one,
    can you please tell me what is the main cause of call Drop on SD channel.
    There is No congestion, No BSIC & BCCH Clash, No path Imbalance and HW issue.
    Where this drop lie in SD Drop or TCH Drop.
    How we can rectifies this drop.
    Vendor Huawei.

    13th February 2011 at 00:23 #65764 Reply
    Rex
    Guest

    Hi Johny,
    1. Are there both SD drop and TCH drop in the same time?
    2. Are TCH drops occurring in the same TRX where SDCCH is declared or SDCCH drops in one TRX and TCH drops in another? If in the same TRX then the issue is that TRX.
    3. Now, what is the cause? Radio, BSS, TC drops?
    4. What is interference on Idle timeslots, what is percentage of UpLink quality HO (this is to ensure you might have interference in uplink)?

    Regards,
    Rex

    14th February 2011 at 06:28 #65765 Reply
    johny
    Guest

    Thaks rex,
    we are using this formula for TCR
    is that we including Call Drop on SD Channel in this formula

    TCR Formulae :
    100-ZTR304A: CELL_RATE_TCH_CALL_DROP_EXCLUDE_HO
    ZTR304A = CM33/(K3013A+CH323+CH343-CH313-CH333)

    rex
    only SD drop due to poor level & Quality in uplink.

    I think for TCR,
    SD channel should not comes in picture but durring immediate assignment it may comes.
    please share yours view.

    14th February 2011 at 09:19 #65766 Reply
    Josue
    Guest

    Problem indication:drop due to bad quality
    . Interference-co-or adjacent interference
    solution:
    downtilt interferer cell or cells

    Problem indication-Drop due to other reason
    since there is no urgent conations but the call is dropped its hard to find the reason
    . Generally drops due to other reason indicate a non RF problem

    solution
    .transmission problems
    .dTRU or dRU hardware problem
    .wrong definition of call in MSC BSC
    .Wrong LAC definition in MSC

    14th February 2011 at 14:41 #65767 Reply
    Johny
    Guest

    thks Josue

    I am getting immediate assignment failure in network also on SDCH and TCH both. but for different cells and different Trx.
    The counters are
    1. R4400A:Attempted Immediate Assignments (SDCCH)(times)

    2.R4400B:Successful Immediate Assignments (SDCCH)(times)

    3.R4409A:Attempted Immediate Assignments (TCH)(times)

    4.R4409B:Attempted Immediate Assignment Prodedures (TCH)(times)
    can any boby

    I am getting immediate assignment failure also on SDCH and TCH both. but for different cells and different Trx.

    Can any body tell which KPI leads to stepped UP or Down for Immediate assignment failure

    15th February 2011 at 00:08 #65768 Reply
    Rex
    Guest

    Hi Johny,
    Try to make Drive Test measurement in the areas covering from those cells in order to be sure about interference. Check RxQual, FER etc. In layer 3 messages check for reasons of call drop.
    Regards,

    15th February 2011 at 04:49 #65769 Reply
    Johny
    Guest

    thaks rex

    But Which KPI effected if we are getting immediate assignment failure?whats the couter for?

    15th February 2011 at 13:44 #65770 Reply
    Johny
    Guest

    Any one!!!
    Help Me

    15th February 2011 at 18:12 #65771 Reply
    Brother
    Guest

    hardware problem can be, congestion might, interference is also possible, if site is covering large area change rxlevaccessmin or tilt milt…

    15th February 2011 at 21:47 #65772 Reply
    Rex
    Guest

    Hi Johny,
    KPI affected by immediate assignment failure is SDCCH success rate. Check threads regarding immediate assignment failure, for example thread=4091 or do search by topics you are interested.
    Regards,
    Rex

    17th February 2011 at 09:28 #65773 Reply
    Johny
    Guest

    High utilization (above 60%) increased the call drop possibilities. AMR/FR tuned to 55%?

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