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SDCCH SUCCESS RATE

Viewing 9 posts - 1 through 9 (of 9 total)
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  • #59107 Reply
    MKT
    Guest

    Hi all,

    What could be the reason for low SDCCH SUCCESS RATE in a cell when the SDCCH DROP & SDCCH BLOCKING are normal.

    The cell is of ericsson and the immediate neighbour is Nokia cell.

    Inter MSC/BSC handover are checked and are defined.

    Where to check?

    Regards

    MKT

    #59108 Reply
    MKT
    Guest

    ERICSSON CELL STATS

    CellName
    TRW001A
    TRW001B
    TRW001C

    TRX
    6
    6
    6

    TCH Availability Rate
    100
    82.39
    99.95

    TCH Traffic (Erlang)
    17.79
    12.05
    4.22

    TCH Drop (%)
    10.85
    31.26
    22.68

    TCH Blocking (%)
    0
    0.45
    0

    No. of SDCCHs
    47
    55
    39

    SDCCH Call Success Rate
    58.87
    72.31
    72.02

    SDCCH Drop (%)
    9.92
    8.99
    3.82

    SDCCH Blocking
    0
    0.07
    0

    Outgoing HO Success Rate
    89.35
    95.42
    92.02

    Incoming HO Success Rate
    93.27
    94.86
    93.24

    Call Success Rate
    98.65
    99.55
    99.48

    HR Traffic
    0.78
    2.91
    0.01

    #59109 Reply
    MKT
    Guest

    The problem started to appear one month back when the Ericsson carried out an activity to redefine the LACs in their network.

    #59110 Reply
    Pix
    Guest

    SDCCH DRop is around 9% !! That’s not what I’d call normal 🙂

    What I see is:
    High TCH drop
    High SDCCH drop

    Then, Call success % is excellent and HO success are good too. That proves that the way Ericsson are computing their indicators is very obscure ! (for me, at least)

    Could you please state also the average duration of the SDCCH and TCH in the cells ? If it is very short, then that confirms my suspicion…

    With such bad QoS I must suspect a hardware failure, or most probably a wrong configuration of the equipments or interfaces. I would investigate if the drops happen on some TRX only, or even on some TS only. I would check also what is the cause of the drops (with indicators, or with drivetest)

    If there is a random pattern, then the failure is probably located further up in the core network (Ater ? TC ? A interface ? MSC ???). My instinct is leaning towards A and Ater misconfiguration, or a board failure somewhere.

    #59111 Reply
    Tukai
    Guest

    MKT,
    Can you please provide values for the following counters ccalls,cmsestab,ccongs,tassall,tcassall,cndrop,thndrop,tfndrop.
    im not convinced with the kpi figures below

    #59112 Reply
    Has UK
    Guest

    Its the RACH sent from the mobile, two cells with the same BCCH anser the request. Awaitng response from handset which completes access on closer cell not responding to the futher cell (normally higher ground height). This does not affect KPI’s so can be ignored. Otherwise find the clashing BCCH and perform retune.

    #59113 Reply
    MKT
    Guest

    THE L3 MESSAGE DETAIL FOR CALL END

    MS1
    Release

    Time: 13:54:06.39
    MsgCtrlOperation :
    Transaction identifier : 0
    Protocol discriminator : (3) Call control; call related SS messages
    Message type : 45

    Message dump (Hex):
    03 2D

    MS1
    Time: 13:54:06.39

    Call End
    NW initiated release
    Call duration: 109094 ms

    #59114 Reply
    MKT
    Guest

    MODE REPORT

    MS1
    Time: 13:54:06.39

    Call End
    NW initiated release
    Call duration: 109094 ms

    #59115 Reply
    halen_nguyen
    Guest

    how to make a statistic of times number seize SDCCH channel by nemo analyze, expect people to help

Viewing 9 posts - 1 through 9 (of 9 total)
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