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Viewing 15 posts - 16 through 30 (of 74 total)
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  • #48780
    Gito Prastomo

    Dear Jalal,

    Power COntrol must be applied in SFH Network, because it it use mybe the same MAL List or sequential MAL list depend on your configuration (1×3, 1×1 , 2×2 etc).
    In my experienced, it will increase the performance in high load network.
    If you apply SFH in low/very low load network, the performance could be degraded than before. But ensure that all configuration are correct.


    could you please give me the main formula which should be used for GPRS.
    What should we look at in term of GPRS.

    GIto Prastomo

    Dear Jalal,

    What do you mean with terms of GPRS?
    The SFH is just modification in radio interfaces.
    What KPI do you mean ?


    jalal, you should really spend more time writing your questions. it is very confusing, and lacks details.


    I mean, we are already defined 2 PDCH on each cell, what do u look at to see the IP Throughput formula..
    is there anything else u look for to optimiza the GPRS perfomance


    What is the relation between your two questions?
    Don’t come with another inquiry while the first hasn’t ended yet.


    “what do u look at to see the IP Throughput formula ?”

    To see the IP throughput, look at the sun for a while, and blink your eyes in front of a black board.


    in Ericsson , there two type of TCH Drop( TCH Drop rate & Subscriber TCH Drop) what are the difference between them?
    also if you have TCH Drop due Sudden lost, does it depend any how to Subscriber TCH Congesyion?


    The congestion can’t lead to a call drop :
    case 1 : there is no congestion and the TCH is allocated for this one user–> call setup successful.
    case 2 : there is congestion and the TCH is not allocated –> call setup failure.

    As you can see, the congestion impacts the call setup, not the call drop. Call drop is occurring after the TCH has been assigned : the radio link is already allocated. If there is congestion in the cell, it will not release an “active” TCH. It will just prevent new TCH allocation.

    Regarding your other question, i cannot answer (i’m not from ericsson)


    Da Architect

    It’s been a long time, but now I am back!

    Dear Pix you are right about tch drop and congestion when we talk from Alcatel point of view. But in ericsson the counter of TCH Drop [TNDROP] increment with another counter [TNRELCONG] that increment upon congestion on TCH Transcoder or Ater during assignment to better or worst cell. so the correct equation for call drop rate must be adjusted to be as following: 100 * (TNDROP – TNRELCONG)/(TCASSALL + ((SUMIHOSUCC – SUMIABSUCC – SUMIAWSUCC ) – (SUMOHOSUCC – SUMOABSUCC – SUMOAWSUCC))))

    to reply for Sam questions:
    subscriber tch drop must be the above equation, while the other tch drop rate is calculated without taking into consideration the TNRELCONG and HO and AB and AW.

    also note tch drop due to sudden loss is not related to tch congestion… as i mentioned above, counter TNDROP increases with TNRELCONG.

    I hope i made it clear.


    welcome back mister !

    i tell you : your answer was clear…

    but it’s ericsson that is not very clear 🙂


    Hi all,

    I hav been working in nokia systems and concern about sdcch drops which shows more than 3% for many cells. What could be the list of causes to figure out the issues?


    Hello Karthi,

    for sdcch drop, you can investigate the followings :

    hardware/software problems (dynamic SDCCH ts allocation, TCU failures, RSL failures, TRX failures)

    radio problems : Especially interferences on the frequency of the TRX’s that is carrying the SDCCH’s. Low coverage (low rxlev) can also have a big impact on the SDCCH drop rate (rural areas, mostly, as soon as avg rx lev of the cell is less than -88dBm)

    Don’t forget to check the path balance of your “SDCCH” TRX’s.

    handover problems : if SDCCH handover is enabled, then you might want to disable it and check the results.

    You can also check the average duration of the SDCCH seizure : if it is above 5 seconds, then there might be “hanging” DTAP message during the SDCCH phase. If the SDCCH phase lasts too long, it increases the risk of drop.

    That’s about it…
    just a reminder : the SDCCH congestion has no effect on the SDCCH drop.




    Thanks for ur valuable suggestions Pix.we observed some path balance issues with TRXs(sdcch) and changed the sdcch slot to other TRXs for observation.
    Our planning guys enabled antenna hopping and got more improvement in sdcch drops.Do anyone aware of the significance of ant hopping?



    i’m glad your problem was fixed.
    antenna hopping oesn’t exist (it would be funny to see antenna hopping onto each others though). I think your colleagues actually activated the frequency hopping 🙂 Probably BBH.

    It means that you were having path balance issues and interference issues. Time for a new frequency planning 🙂

Viewing 15 posts - 16 through 30 (of 74 total)
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