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TCH congestion

Viewing 15 posts - 1 through 15 (of 19 total)
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  • #57939 Reply
    sd
    Guest

    some of our cells have no congestion while some have very high congestion for the same number of TCH channels. what might be the reason, can anyone help me out??

    #57940 Reply
    Pix
    Guest

    High amout of traffic

    #57941 Reply
    sd
    Guest

    acc to our Erlang B table if we calculate the traffic, we still have caacity but we get congestions before reaching the rated capacity. In some cells we have TCH congestion even in case of low traffic.

    #57942 Reply
    Pix
    Guest

    could you give me some numerical values, please ?

    check that all your TRX are up & running (availability, alarms ?)

    #57943 Reply
    aso
    Guest

    This could be that those cell might have high interference.

    #57944 Reply
    Rex
    Guest

    Hi sd,
    Check traffic for each TRX. Do all TRXs having any values? Perhaps one of TRXs has 0 Erl. If Yes, work on that TRX (reset TRX, reset corresponding TCUC, change TRE, etc).

    #57945 Reply
    sd
    Guest

    hello pix,
    in one of our site for 56 TCH channels (half rate), traffic is 26.83 erl and the corresponding congestion is 26.59% while for the same cell, at traffic 35.62, congestion is 2.15%.

    #57946 Reply
    pix
    Guest

    could you check how much is the traffic carried in half rate, and how much in full rate ?

    i suspect there i either:
    1/ no half rate in the cell (parameters wrongly set ?)
    2/ some trx’s are down

    cheers,
    pix

    #57947 Reply
    sd
    Guest

    For 56 HR TCH channels,total traffic is 50.49 Erl where 4 Erl traffic is FR while 46.49Erl is HR traffic with 53.64% TCH congestions.

    #57948 Reply
    Pix
    Guest

    SD,

    In each situation, 56 HR TCH:

    1/ Traffic = 26.83 erl, Congestion = 26.59% —> Very abnormal, congestion way too high

    2/ Traffic = 35.62 erl, Congestion = 2.15% —> Normal

    3/ Traffic = 50.49 Erl, Congestion = 54% —> Normal

    In the first situation, I think the capacity you compute is not corret. Not all TRX are actually able to carry traffic.

    (or all TRX are OK but they are able to carry only full rate, not half rate)

    In other cases (2 and 3), no visible problem.

    #57949 Reply
    Ayat
    Guest

    DEAR ,ALL

    REALLY I APPRCIATE YOUR SUPPORT ,

    I NEED TO UNDERSTAND THE GSM CALL PROCESDURE OUR VENDOR USE COMPLEX DESCRIBTION FOR THE PERFORAMNCE SYSTEM SO . IT IS DIFFECULT TO UNDERSTAND IT ,

    COULD YOU HELP US TO DEAL WITH THESE COUNTERS.

    SDCCH Dropped call total number
    SDCCH attemption total number
    SDCCH overflow total number
    SDCCH allocate failure number in busy time
    Number of SDCCH seizure attempts for assignment
    Number of SDCCH seizure success for assignment
    Number of SDCCH seizure failure for assignment
    Number of SDCCH seizure attempts for handover
    Number of SDCCH seizure failure for handover
    Number of SDCCH allocation success for assignment
    Number of SDCCH allocation failure for assignment
    Number of SAPI3 link establishment requests on SDCCH (MO-SM)
    Number of SAPI3 link establishment requests on SDCCH (MT-SM)
    Number of SDCCH drops due to handover failure
    Number of SDCCH drops
    Number of SDCCH assignment attempts
    Number of SDCCH assignments success
    Number of SDCCH assignment failure
    Number of SDCCH drops due to loss of contact with RANA
    Number of SDCCH drops due to radio link failure
    Number of SDCCH drops due to LAPD link failure
    Number of SDCCH drops due to OMC-R forced release
    Number of SDCCH drops due to forced release by other calls
    Number of SDCCH drops due to handover failure
    Number of SDCCH drops due to other failure
    Number of SDCCH drops
    Number of SDCCH link failures
    Number of RANA link releases due to other cause on SDCCH
    Number of SDCCH short messages drops
    Number of SDCCH seizure attempts for assignment
    Number of SDCCH seizure success for assignment
    Number of SDCCH seizure failure for assignment
    Number of SDCCH seizure attempts for handover
    Number of SDCCH seizure success for Handover
    Number of SDCCH seizure failure for handover
    Number of SDCCH allocation attempts for Assignment
    Number of SDCCH allocation success for assignment
    Number of SDCCH allocation failure for assignment
    Number of SDCCH allocation attempts for handover
    Number of SDCCH allocation success for handover
    Number of SDCCH allocation failure for handover
    Number of SDCCH assignment attempts
    Number of SDCCH assignment success
    Number of SDCCH assignment failure
    Number of SDCCH handover failure
    Number of SDCCH handover success

    could you explain

    Number of SDCCH assignment attempts 18149
    Number of SDCCH assignments success 17745

    Number of SDCCH allocation attempts for Assignment 18150
    Number of SDCCH allocation success for assignment 18149

    what does mean allocation

    does this procedure before or after the assignement

    what does mean siezed and alloated assign

    #57950 Reply
    Pix
    Guest

    Attempts mean : the SDCCH channel is given to the MS (the BSC have successfully allocated the subchannel in the cell), in other words the reference of the SDCCH timeslot & subchannel is sent to the MS in the Immediate Assignment.

    Success : the MS has replied to the Imm Asg, and therefore the MS has succesfully landed on its SDCCH subchannel.

    if you have 100 attempts and 90 success :

    it means 10 attempts did not becme success. 10 MS have not succeeded to land onto their SDCCH. Probably radio problems : the SDCCH is interfered, or the MS is too far away (bad coverage)

    #57951 Reply
    Ayat
    Guest

    Hello pix

    thanks

    Success : the MS has replied to the Imm Asg, and therefore the MS has succesfully landed on its SDCCH subchannel.
    is that mean success is seized .???

    #57952 Reply
    Pix
    Guest

    success = seized, yes.

    #57953 Reply
    Ayat
    Guest

    hello All

    Number of MOC random access attempts = 926

    Number of successful MOC random accesses= 883

    Number of CM service requests of MOC= 711.

    926-883=43 why failure 43

    883-711=172

    could you expialn these number??

    from the defination we see that Number of successful MOC random accesses=Number of CM service requests of MOC but in the result it is not

    Number of CM service requests of MOC= 711
    This counter counts the number of accesses due to CM SERVICE REQ of MOC. After BSC receives the EST_IND message, if the access cause in the layer-3 information in this message is “CM SERVICE REQ”, this counter increments.
    This counter is used to find out the frequency of the access due to CM SERVICE REQ of MOC.

    Number of MOC random access attempts = 926

    It represents number of random access requests due to MOC. If
    TA does not exceed cell range, BSC treats random access
    request as valid MOC and increments the counter.

    Number of successful MOC random accesses= 883
    It represents the number of successful random accesses when
    BTS assigns a channel to MS due to MOC. After successful
    access, MS sends EST_IND to BSC through BTS. Counter
    increments when BSC receives EST_IND.

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