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SPDCH

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  • #57767 Reply
    SHELDON
    Guest

    Hi Safar,

    Hmmm…it would be very nice if I could go on vacation that often. I was just a little busy that’s all.

    Yes, if you want to have 30 PDCHs in a cell( whether they’re E-PDCH, G-PDCH or B-PDCH), you can define 16 as FPDCH +SPDCH and the remaining 14 will be allocated on-demand. I’m however curious to know why you would define as many as 16 FPDCH/SPDCH in a cell. Is your voice traffic very low or you have many TRXs in the cell?

    Regards,
    SHELDON

    #57768 Reply
    safar
    Guest

    hi sheldom,

    Ok buddy right .but here u are talking abt bpdch but we are discussing abt edge.

    So in my nw opdch is 100% so if we again talk abt my cell in which 30 edge timeslot 16 fpdch+spdch and remaining 64 k as switchable ok but here if still my
    voice timeslot will be idle then i can use
    them for cs1 cs2 bpdch traffic .
    In short i can use more than 30 timeslot for edge as well as gprs.right?

    #57769 Reply
    SHELDON
    Guest

    Hi Safar,

    I mentioned B-PDCH because I was trying to emphasize the fact that an FPDCH/SPDCH can be any kind of PDCH (E-, G- or B-BPDCH).

    Any idle TCH can be used as a PDCH, and the PDCH can be an E-PDCH, G-PDCH or B-PDCH. The only limit to the number of PDCHs you can have in a cell is the number of idle TCHs in the cell. If you have configured 30 EDGE timeslots( E-PDCHs), then any other PDCH which is allocated above 30 will be a B-PDCH. I hope this answers your question.

    Regards,
    SHELDON

    #57770 Reply
    safar
    Guest

    hi sheldom,

    Ya right buddy thanks and can i have ur mail id ?

    #57771 Reply
    Prabeen
    Guest

    Hi Sheldon,

    We use Ericsson system. The allocations are as follows:

    TBFDLLIMIT – 20
    TBFULLIMIT – 20

    Could u tell me wat will be the impact of this on customers?

    Also, i have allocated 2TS dedicated, 1TS On demand. In most of my cells i face “High Packet Channel Allocation failure”. Even the CS traffic is low in these cells. Could u tell me wat parameters should i look into n y is happening???

    Pls help.

    #57772 Reply
    SHELDON
    Guest

    Hi Prabeen,

    Your settings of TBFULLIMIT and TBFDLLIMIT mean that you PREFER to have a maximum of 2 TBFs per PDCH. This means that your BSC will attempt to allocate more PDCHs for new TBFs when the current number of TBFs per PDCH is 2.

    From a user perspective, the effect is relative. Generally, each user will experience a higher throughput when the number of TBFs per PDCH is lower (ie, the lower the settings of TBFULLIMIT and TBFDLLIMIT, the better the throughput per user).

    PDCH allocation failures can be caused by:
    1. High voice traffic(which does not apply to you)
    2. PCU congestion
    3. PCU hardware faults
    4. PCU parameter settings (ONDEMANDGPHDEV)
    4. Faulty TRXs on the cells

    If you have the failures occurring on several cells on the same BSC, then it’s definately a PCU problem. Check PCU congestion and the setting of the ONDEMANDGPHDEV parameter(it should not be too low). You can also try resetting the PCU, ‘cos sometimes some RPPs don’t work properly.

    Failures in individual cells on different BSCs are caused by problems in the cells themselves (eg TRX or other hardware fault).

    Regards,
    SHELDON

    PS:
    Safar,
    My email address is derysheldon@yahoo.com

    #57773 Reply
    Prabeen
    Guest

    Hi Sheldon,

    Thanks a lot for your explanation. I guess The Cells are not PCU dependent coz so many cells irrespective of BSC are having this problem.

    Hence i have asked my people to get Gb Link report where in i can c most of the BSC are having congestion in Gb link. But even cells where this congestion is not thre also, we are facing failure.

    One guess: How much percentage of PCU should be reserved for Dynamic TS? Is it 33%? But v have allocated only 25%. Any idea about this?

    #57774 Reply
    SHELDON
    Guest

    Hi Prabeen,

    Your setting of ONDEMANDGPHDEV is ok. However, if your PCU utilization is more than 75%, then your setting of 25% will not work as desired, so check your levels of PCU utilization.

    Also, in your earlier post, you said you’ve activated 2 fixed PDCHs and 1 on-demand. How did you define the number of on-demand timeslots? I thought their no. was not fixed, but varies depending on the data usage level in the cell?

    Regards,
    SHELDON

    #57775 Reply
    Prabeen
    Guest

    Hi Sheldon,

    I can explain. We have made use of Flexi Abis plan. then we have kept the following parameter:
    NUMREQEGPRSBPC=3
    FPDCH=2
    here we are not allocating a fixed PDCH. But the extra BPC will work as On Demand EGPRS timeslot supporting (64Kbps).

    Normal On demand does not need any allocation but it supports only GPRS (16Kbps)

    I have checked the PCU congestion, even that is not congested. But my SGSN utilization is around 98% in all BSC.

    #57776 Reply
    Prabeen
    Guest

    Also,

    Pls help me in dimensioning a good report for GPRS. I need to ask my vendor (Ericsson) for the BO. before anyone got idea on wat all should i enquire.

    Pls help

    #57777 Reply
    safar
    Guest

    Hi sheldon,

    ya prabeen is right.u do not need to define any 16 kbps timeslot for opdch and if its 100% and there is need of gprs traffic and idle tch will be there then it will go on

    while in egprs u can define fpdch+spdch+ switchable edge timeslot.

    for this switchable timeslot we need to define 64 kbps on abis but u can this timeslor for voice when there is less edge traffic.

    sheldom remember my earlier post in which i asked abt 30 edge timeslot in that there was 16 fpdch + spdch and remaining 14 were switchable fixed on abis(64 kbps) but on radio level they can also fofr voice

    #57778 Reply
    shah
    Guest

    Can anybody tell me what happen if the T3212 Timer for MSC put less than T3212 Timer for the CELL Site/BSC.
    Thanks in advance

    #57779 Reply
    SHELDON
    Guest

    Hi Prabeen,Safar,

    Ok, I understand. I actually have a similar implementation in my system. I was referring to general PDCHs, but if you’re talking abt EDGE, that’s understandable.

    Prabeen,
    What do you mean by dimensioning a good GPRS report?

    Regards,
    SHELDON

    #57780 Reply
    safar
    Guest

    Hi sheldon,

    in previous we discussed abt that in dl per pdch max tbf are 16 and in ul its 7 per pdch. and per pset we have max 32.

    so now in case if i have 5 pdch in one pset then if i calculate per pdch wise ul+dl tbf then it means (16 dl+7 ul)* 5 edge timeslot = 115 tbf at a time? is it right buddy?

    #57781 Reply
    SHELDON
    Guest

    Safar,

    You have to appreciate that there are 2 different limits. Per PSET, the maximum number of TBFs is 32.

    However, if you have only 1 PDCH in the PSET, then you can have a maximum of 16(DL) or 7(UL) TBFs in the PSET. 16 and 7 refer to the maximum number of TBFs per PDCH.

    If you have 5PDCHs in the PSET, then you can have a maximum of 32 TBFs in the PSET, not more.

    Regards,
    SHELDON

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