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SD Blcking-SD cong,TCH Blcking-TCH cong

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  • #57372

    Hi all,

    Can anybody throw some light on the difference between SD blocking-SD congestion,TCH blocking-TCH congestion…..both formulawise and general concept wise..



    Its really sad that nobody has been able to answer these questions


    Those names are just names…
    It just depends what formula your operator wants to attach to these names.

    Block = Congestion, those are normally the same, but the operator might use a different formula for each.


    But Mr. Pix what exactly the difference between the two entities.


    Hi Vic

    My idea about it is that SD BLOCKING and TCH BLOCKING may be caused by many reasons. It can be optimization issue(such as improper definition of parameters, interference and some other RF stuffs),hardware problem such as faulty TRXs or can be also congestion as well.

    SD and TCH congestion however is due to failure to assign a certain channel (SDCCH or TCH)mainly because theres no available channel for assignment.

    On the level of congestion however, if TCH and SDCCH BLOCK is due to Congestion, then at this point BLOCKING and CONGESTION are just similar. Hope you get my point.


    If all the radio resources are full and not availble for Sd assignthen it come into congestion and if at a particular time call is attempted and fails then it is called Blocking

    i think u got my point n ur sol is there..


    Dear Friends/Seniors,

    1)Any body can tell me the difference between SDCCH blocking & SDCCH drop,SDCCH Congestion with specific reason?

    2)Also differece between TCH congestion,TCH drop,TCH Block with specific reason


    congestion means that when ms try for sd channel and all the sd channels are busy it means there is sd congestion
    SD block means ms want sd channel but not able to get it due to congestion,hardware issue,interference, or any other issue that case is sd block
    means sd congestion is one of the reason for sd block
    Sd drop is that case when ms request for the sd fulfill by bts but not able to convert that sd into tch

    Same in case of tch drop,block,congestion


    Whenever all SD ch are filled and are not available for the allocation that is Sd congestion (time in sec)and during this time interval the attempts made goes into the Blocking bucket ( in %age)same is the case for TCH.

    Pramod S B

    Congestion and blocking very much related but not the same.But main cause for blocking congestion only.That means all the slots available for sdcch is occupied and no resource available for call setup then we can tell call block happened due to congestion.But blocking is some thing broader , it can happen due to lots of other reasons too.for example due to equipment block (HW issues).improper Rf conditions, issue related with transport n/w etc.


    hii all,

    somebody tell me, how logical channel works on physical channel, i also well understood about both types of channels


    What are the factors that induce TCH blocking and how can I unblock them?


    Hello Benedict!
    TCH blocking is when there is not enough TCH resources to handle traffic. So either you have availability issues if the resource planned is suppose to be sufficient either you should upgrade (Radio, TX or BSS part).


    can anyone tell me that what becomes the ranges of TCH & BCCH in GSM?

    Anil Bhoyar

    SD blockages and TCH Blockage when Low Traffic.

Viewing 15 posts - 1 through 15 (of 16 total)
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