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GPRS

Viewing 15 posts - 16 through 30 (of 40 total)
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  • #51416 Reply
    safar
    Guest

    Hi pix,

    Can u help me for egprs in uplink how many timeslot wil be assigned by bts and in downlink ?

    it will assign according to multislot class in downlink but in uplink it will be always one?

    #51417 Reply
    pix
    Guest

    for 1 PDCH coded in MCS-9, there is a need of 4.5GCH

    ie.
    1 MS using 4PDCH in DL @ MCS9, it needs 4*4.5GCH = 18GCH

    in UL, a MS can use more than 1 PDCH. It can use 2 PDCH without any special feature… (2+2 or 3+2)

    There is also the new feature “extended dynamic allocation”, which allow the following configuration : 1+2, 1+3, 1+4, 1+5, 2+3, 2+4, 3+3

    Anyway, the dimensioning of the GCH is always done in DL. When you got your result, for example the link needs “50 GCH”… then you design an ABIS link with 50GCH. There will be 50GCH in DL and 50GCH in UL. 1 GCH is always defined symetrically.

    pix

    #51418 Reply
    SAFAR
    Guest

    Hi pix,

    u are right by dynamic extended allocation one can provide 4 timeslot in uplink

    but my question is if first i am attaching egprs at that time one timeslot will reserve in ul and according to class i will get 3 4 timeslot in downlink.

    but after getting dl timeslot my uplink timeslot will release from particular pdch

    and during runnig my session if i need ul timeslot then will it enable on same pdch or alredy its reserved.

    #51419 Reply
    pix
    Guest

    the UL PDCH will be allocated on a TS where there is already one of the DL PDCHs (for this MS). If no UL PDCH is available (let’s say they are all fully used by other MS), then the DL PDCH will be reallocated somewhee else so that the UL PDCH can be established.

    pix

    #51420 Reply
    Ds
    Guest

    Hi all,

    plz clear my doubt.
    say if for a session, in UL one timeslot is used & in DL 4 timeslots.
    say if during the session, there is no data to be transferred so thet one timeslot will get free or used in DL, or there is some continuous slow of signalling etc.

    thanks in advance

    #51421 Reply
    safar
    Guest

    hi pix,

    Thats right.but i want to know that once i got pdch in ul and also i got dl pdch and i am surfing then after that ul pdch will release from that pdch ?

    And if it release and during surfing i need ul pdch again then what will happen?

    #51422 Reply
    Pix
    Guest

    Safar,

    the UL TBF will be released, and re-established. DL and UL TBF are totally independant, they can be released and reestablished without impacting the concurrent TBF (concurrent = TBF in the other direction)

    So yes, the UL PDCH is released and will be be reallocated when needed, if it is still avaiable.

    DS,
    I’m sorry, i don’t understand your question
    pix

    #51423 Reply
    Ds
    Guest

    Hi Pix,

    u said UL n DL TBFs are independent.

    my ques was suppose an MS is using 4+1 PDTCHs. now in case of no UL data to be sent, will that 1 PDTCH be used in DL or can be used anywhere else.

    also,during DL data tranfer going on, is some UL transactions(not data) take place simultaneously for a particular MS.

    #51424 Reply
    safar
    Guest

    hi pix,

    Thanks .can u tell me after how much time my idle ul or dl tbf will expire?i mean which timer?

    #51425 Reply
    pix
    Guest

    DS,

    The UL PDCH is not used by the MS, so the UL TBF is released. It cannot be “reused” for DL.

    Look.. A ms in 4+1 will have a timeslot allocation that looks like this :

    (note : the PDTCH is the logical channel used to carry Data on a PDCH)

    DL PDCH allocation:
    TS2=PDTCH
    TS3=PDTCH
    TS4=PDTCH+PACCH
    TS5=PDTCH

    UL PDCH allocation:


    TS4=PDTCH+PACCH

    when the UL PDCH is not used, the allocation will be :

    DL PDCH allocation:
    TS2=PDTCH
    TS3=PDTCH
    TS4=PDTCH+PACCH
    TS5=PDTCH

    UL PDCH allocation:


    TS4=PACCH

    However the MS will still send “Signalling” (not Data) on the UL PDCH, once in a while. This is the “UL PACCH”.

    The second question : Yes, in UL, the MS will have to send RLC/MAC Acknowledgments. It is done through the UL PACCH.
    Also it is probable that once in a while, after some DL download, the MS will have to send “higher protocol” acknowledgments (TCP Ack).

    It is a little difficult to explain all this on a forum 🙂

    Cheers,
    pix

    #51426 Reply
    Pix
    Guest

    Safar,

    It is managed by several parameters and algorithms, I can’t find the strength to share all this today… perhaps next week 🙂

    cheers
    pix

    #51427 Reply
    safar
    Guest

    hi pix ,

    Thanks .and ya i will be waiting for u on discussion abt thisnon edge?

    u said that ul pdch is released if it is not used but ul pacch will continue upto dl tbf is continue is it right?

    Now in erlc soft limit for tbf per pdch is 2 and hard limit is 32 per pset (in one pset may be 4 or more pdch) so every time when my dl tbf is continue then one ul pacch is occupied?
    And pix have u tested persistent scheduling in egprs ?

    #51428 Reply
    safar
    Guest

    hi pix,

    where are u?waiting for ur reply.

    #51429 Reply
    Pix
    Guest

    Safar,

    check out 3GPP TS 04.60

    UL TBF release can be done with 2 dfferent mechanisms :

    1/ without extended mode
    UL TBF is released T_DELAYED_FINAL_PUAN (about 400ms) after last block has been uploaded.

    2/ with extended mode
    it is released T_MAX_EXTENDED_UL (about 2s) after last block is uploaded. This mode is done if activated in the BSS + if the MS supports it (Rel’4 MS onwards)

    DL TBF is released after a “delayed” time defined by timer T_Delayed_DL_TBF_Rel (equals to T_NETWORK_RESPONSE_TIME = 1.6s in alcatel)

    Best Regards,
    pix

    #51430 Reply
    safar
    Guest

    Hi pix,

    buddy can u tell me how to check this 3GPP TS 04.60 ?

    and the site is 3gpp.com ? if yes then how to check buddy?

Viewing 15 posts - 16 through 30 (of 40 total)
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