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Random Access Success Rate

Viewing 11 posts - 1 through 11 (of 11 total)
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  • #51339 Reply
    Bilal
    Guest

    Hi Guys,

    Random Access Success Rate has the formula : 100 * No. of successful random accesses / No. of random access attempts. Can anybody tell me what is a successful random access? I mean when this counter is pegged?

    #51340 Reply
    Pix
    Guest

    you need to find an ericsson guy… i’m the alcatel guy ๐Ÿ™‚

    #51341 Reply
    Bilal
    Guest

    You can give the Alcatel’s definition for it, I don’t think there will be much difference ๐Ÿ™‚

    #51342 Reply
    Pix
    Guest

    That’s the thing, we don’t have those in alcatel.

    Let’s try to guess.. the MS starts with a channel request on RACH, the “Channel Required” reaches the BSC, and then is counted as a “random access attempt”.

    The BSC sends a Channel Activation to the BTS, if the SDCCH is not congested. Counted as a “SDCCH Request”.

    The BTS replies with a Channel Activation Ack (not counted)

    Then the BSC sends a Immediate Assign Command, counted as a “SDCCH allocated”.

    Maybe in your formula, this is the ratio CHANNEL ACTIVATION / CHANNEL REQUIRED ?

    I really cannot be sure… this indicator is not provided by alcatel. it can be computed manually though.

    #51343 Reply
    Bilal
    Guest

    Got the answer. But it creates another confusion.

    Successful Random Accesses are all except failed random accesses.The failed random access counter is incremented for a Random access received with too high TA, values that are not used or in case of “software file congestion”.

    That means every RACH attempt with less than max TA and defined cause value is a successful Random Access. But Ericsson says poor BSIC planning can be a cause of bad Random Access Success Rate, how is this? Even a phantom RACH intended for another cell must have a valid cause value and hence it must be treated as a Successful Random Access.Any idea?

    #51344 Reply
    pix
    Guest

    you’re right, a RACH on a BCCH is not “failed” even though there is a poor BSIC-BCCH plan.

    in my opinion, the only problem could be a RACH sent on a BCCH frequency that is used as well few kilometers away. In this situation, the second cell might receive this RACH with a distance > “rach timing advance”.

    #51345 Reply
    Ramlakhan Anvit
    Guest

    Hi all.
    What is the meaning of Um interface, thus what does it stands for. I know it interfaces the MS and BTS. But what is the meaning of U and m in Um interface.

    Thanx.

    #51346 Reply
    pix
    Guest

    Hello and welcome to internet.

    Wikipedia / Um interface
    “It is called Um because it is the mobile analog to the U interface of ISDN.”

    Regards
    pix

    #51347 Reply
    paraHO
    Guest

    ‘Um’ is an acronym for “User Mobile”

    #51348 Reply
    pix
    Guest

    hi paraHO,

    glad to see you are still around !

    regards
    pix

    #51349 Reply
    paraHO
    Guest

    Hi Pix – thanks. Just can’t keep away from the forum ๐Ÿ˜‰

Viewing 11 posts - 1 through 11 (of 11 total)
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