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Viewing 14 posts - 61 through 74 (of 74 total)
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  • #48825

    Hi, all.

    We don’t use GoS, so I hope Pix will help…

    But following the definition GoS = num of lost calls/ num of offerred calls it should be the SDCCH included.

    We are obligated by governiment to keep blocking under 5%.
    We have also internal standard:
    to not tolerate SDCCH block above 0,5% except due to LAC border LU and TCH blocking to be under 2%.
    Following strictly the first rule it is eazy to keep GoS under whatever value.

    RACH and PCH have a very big capacity ( messages per hour ).
    RACH – before have RACH blocking we should have very hard problems with TCH resources ( in my opinion ). I saw a recommendation for 12 TRX chennal configuration:
    TRX 1/TS2 – CC6 (BCCH+CCCH)
    TRX 1/TS4 – CC6

    This will triple the RACH resources.

    It will triple the PCH too, but the only solution in case of PCH blocking is LAC splitting.
    I have a agreement with NSS team to be informed when the paging messages per hour are close to the limits.
    This is because I don’t trust the RNO MC8A counter.

    Pix, did you note abnormal values for this counter?

    I hope I was useful.

    Have a nice day.



    Dear Pix,

    Could you please tell me about the abnormal value of the MC8A counter.

    Thank you very much.


    MC8A is not very reliable, but I never studied it very deeply. I don’t know the details… Heads up ! In B10 some additional counters for RACH and PCH are going to be introduced 🙂

    Let’s go back the the GoS : for each logical channel, you must define a GoS :
    0.5 % for SDCCH
    2 % for TCH
    0.1% for RACH
    0.1% for PCH etc.

    For RACH and PCH, in alcatel, as said above, counters are not reliable until B10.

    TNS, in alcatel, in B10, only 2 timeslots can be defined as CCCH. The first one is the BCCH (TS0 of TRX1), and optionally the second is the CCCH (always on TS2 of TRX0).
    More than that is not allowed yet, but we’re pretty sure that’s going to be plenty enough.



    hello Pix .i just want to know what parameter permit the congestion handover. because after you get sddch you need tch but if there are tch cogestion in the serving cell handover must occur . I want to know the parameter you permit that.


    Hi speedy,

    Which vendor? I can help with Ericsson parameters.



    you can activate the forced directed retry, and the “fast traffic handover” (this is alcatel feature i think).
    what are the parameters that control these features ? (thresholds ? activation ?) it is vendor dependent. If you give me the names, I might figure out how they work… perhaps 🙂


    Dear Speedy,
    DR, Forced DR and Traffic Hos are all used for the same purpose. In some cases the normal HO criterion should be fulfilled else there are some other parameters that specify the minimum Rxlev of the neighbour and the min TS available on the nei cell to allow for such HOs to take place. Please specify your vendor, for Motorola and Alcatel I might be able to help, please specify your vendor. else look for Congestion Relief / Directed Retry in your parameter documentation.
    By the way you can also in some vendors set the cells priority to Low thereby it takes calls only if it is the only server else other cells are camped in idle mode. It proves useful for Cells looking in remote with some but not complete overlapping and experiancing congestion. This way you don’t loose coverage and still offload the MS for call setup Traffic.


    Hello guys can anybody make me understand these questions or help me to find them

    someone is asking me these question:

    Existing FP (BBH,SFH1x1 etc)

    Present DCR, HOS, DL/DL Quality



    pix i want to know why tch blocking take place in ericsson even the cells are not fully utilized.
    and do handover failure is one of the reason ?



    tch congestion but the cell is not fully utilized… it means the timeslots are “reserved” for something else than voice:
    – GPRS is using them
    – they are reserved for potential incoming HO
    – some timeslots are unavailable (equipment failure)

    There are perhaps other reasons (?), but I don’t see why HO failure would impact utilization of the cell.



    Hi Nitin,

    Are you using Multiband cells?

    U may be having a lot of calls on the UL.

    Your task is to distribute traffic to to OL.

    Check the counters CNRELCONG & CNRELCONGSUB.

    This measures the TCH congestion in the OL+ UL & OL respectively.

    So the diffrence CNRELCON-CNRELCONSUB gives you calls which cant go through due to congestion on the UL.

    This will give you where your congestion is, UL or OL.

    The other reason could be that you are experiencing congestion in the transcoders. Check counters TFNRELCONG & TFNRELCONGSUB.

    Hope this helps,


    Da Architect

    It can also be reason for Ater congestion.


    May I ask what is the definition for MPD, TNDrop and Drop Network?

    Thank you.

    yonatan bekele

    am from zte GSM-BSS , i have a question about TCH,SDCCH,CALL DROP CLEAR MEANING/DEFINATION PLS.

Viewing 14 posts - 61 through 74 (of 74 total)
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