Erlang software tools...
Generic selectors
Exact matches only
Search in title
Search in content
Post Type Selectors

SD blocked

Viewing 14 posts - 1 through 14 (of 14 total)
  • Author
    Posts
  • 18th January 2009 at 21:05 #55431
    rkb
    Guest

    I have found blocked call(SD block) in TEMS log file.
    The layer 3 message was ‘missing immediate assignment’ while the MS requested channel(AGCH) (in the call attempt retry).
    After 2 retry (as by the max_retransmission parameter)the call was blocked.and the layer 3 message was ‘No immediate assignment’.
    What does that layer 3 messages mean?Does it mean to any specific cause for that Block?
    I know that thats a SD block.But I couldnt find the reason for that block.There supposed to be no SD blocking.

    20th January 2009 at 12:25 #55432
    rkb
    Guest

    why there was no immediate assignment command from the bts after ms requested for channel by RACH?..what may be the cause?..

    20th January 2009 at 18:12 #55433
    Pix
    Guest

    This is normal,

    In case the SDCCH channels are all busy (= high sdcch congestion rate), then the BTS doesn’t have to reply to the MS.
    The MS will then retry by itself, by sending a second and then a third CHANNEL REQUEST.

    This is a standard mode of operation.

    There is feature called “immediate assignment reject” that can be activated, so the BTS will send a message (IMMEDIATE ASSIGNMENT REJECT). This is not mandatory though. It works better this way though (generates less sdcch congestion), so I usually recommend to activate it.

    20th January 2009 at 22:25 #55434
    rkb
    Guest

    hi Pix,
    Other then SD Congestion,is there any other reason which may cause bts doesnt have to reply to ms?
    Because,I found no SD congestion for that cell fom the statistics.

    “There is feature called “immediate assignment reject” that can be activated, so the BTS will send a message (IMMEDIATE ASSIGNMENT REJECT).”
    thats mean we have to enable this feature to get “immediate assignment reject” in case of SD congestion?

    20th January 2009 at 23:09 #55435
    Pix
    Guest

    hi,

    other possibility: the BTS never received the channel request in the first place. A problem of poor path balance (problem of UL reception), or just bad coverage ?
    Or interference on the UL BCCH?

    for the 2nd question: yes

    23rd January 2009 at 15:25 #55436
    TNS
    Guest

    Hi, Pix.

    If the MS request is filtered using RACH_TA_FILTER is there any specific message via air interface?

    BR

    23rd January 2009 at 17:45 #55437
    Pix
    Guest

    TNS,
    No DL message at all.
    The MS will retry MAX_RETRANS times to send a CH_REQUEST but there’ll never be an answer from the BTS.

    7th February 2009 at 23:31 #55438
    TNS
    Guest

    Yes, I know it…
    So it’s another possibility (for answer of the main case )…

    BR

    8th February 2009 at 08:27 #55439
    Pix
    Guest

    Oh, ok, i got it now. the question mark threw me off the scent 🙂

    8th February 2009 at 10:55 #55440
    TNS
    Guest

    HI, Pix

    I was almost sure, so it was a question.
    After you confirmation it was a “conclusion”.
    (I know it = I knew it – my mystake ).

    BR

    8th February 2009 at 14:33 #55441
    Pix
    Guest

    We are getting to a serious degree of subtlety here… 🙂

    26th January 2011 at 04:54 #55442
    mnr
    Guest

    immediate assignment

    5th April 2011 at 19:13 #55443
    GSM ENTHUSIAST
    Guest

    the missing immediate assignment would definetely mean there was no sd allocated.This could be due to more reasons other than blocked SD.simply put,an sd assignment failure.could be due to a lack of sd resources,radio issues,TX issues between BSC and BTS…etc

    1st August 2016 at 13:21 #55444
    Rachael
    Guest

    how many call attempt retry is possible before call block?

  • Author
    Posts
Viewing 14 posts - 1 through 14 (of 14 total)
  • The forum ‘Telecom Design’ is closed to new topics and replies.