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VSAT Sites

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  • #46839 Reply
    Sam
    Guest

    We have high delay in call setup for a VSAT site.What could be the issue and what’s the resolution.

    #46840 Reply
    Pix
    Guest

    Delay is due to the time of travel (round trip time) between BTS and BSC… You can’t do anything, except bringing your satellite closer to the surface of the earth.

    Or inflate earth and make it bigger, so your BTS is closer to the satellite.

    Seriously, only ensure that all call are succesfully setup, without timer expiry. You cannot do anything else. You cannot speed up the call setup duration.

    #46841 Reply
    SAM
    Guest

    I guess inflating the earth would turn out to be difficult.

    Have found that there are AMR traffic in the vsat site even though AMR is diabled in its BSC.What could be the reason

    #46842 Reply
    Pix
    Guest

    that is surprising… are you using AMR on other BTS ?

    It has to be linked to some parameters in BSS or NSS. Maybe your calls are setup in AMR per default, from NSS or TC side.. (??)

    #46843 Reply
    Sam
    Guest

    The AMR traffic is detected in the Uplink traffic (from the BTS side).Then how could it be transcoder or switch.

    #46844 Reply
    Pix
    Guest

    Sam,

    If I were in your case, I would raise the issue to the equipment’s manufacturer (nokia ? ericsson ? alcatel ?). This issue is too “weird” to be solved here…

    You must have some kind of technical post-sales service with them, don’t you ?

    #46845 Reply
    Da Architect
    Guest

    When activating AMR in VSAT sites, I faced problems in Frames Erased and this case can be more seen or detected in case of AMR HR(low codecs). I look forward to find a solution, but it is hard since the AMR HR hopes on different codecs => diff. speed; while the VSAT round trip time is const. Please correct my idea if it was wrong. and i would really appreciate any other suggestions concerning this AMR via VSAT subject.

    Regards,

    #46846 Reply
    Pix
    Guest

    Da Architect,

    it is indeed complex.. the codec used can’t affect the roundtrip time. The time of travel is still the same, whether you are in FR or HR.

    Maybe your issue is more related to the fact that the “AMR change orders” arrives too late ?

    For a while, just to test : Can you try to “freeze” your AMR codecs to only one codec in HR (a safe one) and one codec in FR (a safe one as well).

    You might degrade voice quality a little bit, but at least you can isolate your problem:

    1) if no more call drops : it is linked to the process of changing the codecs during the call.

    2) if call drops are still here :
    2a) disable AMR FR
    2b) enable AMR FR and disable AMR HR
    2c) disable all AMR and use only EFR

    that should give you an idea of where the problem is occuring 🙂

    regards,
    pix

    #46847 Reply
    Jack
    Guest

    Hi,

    Anybody implemented ..Abis over VSAT for E/// BSC and BTS ?

    #46848 Reply
    John
    Guest

    I did this in The Sahara
    Have you tried the Abis over sat feature

    Abis Over Sat Feature description :

    This feature offers satellite transmission on the interface between the BTS and the BSC (the Abis interface). Using satellite transmission gives about 250 ms delays due to the long distances. The GSM standard specifies shorter delays. Longer delays leads to interruptions of the LAPD link. This feature will allow for a longer delays while maintaining the synchronisation on the transmission link.

    #46849 Reply
    Kuma
    Guest

    Just theoritical thing…
    In Motorola system Call Set-up is faster, because RRM is located in the BTS, instead in BSC. Actually in Motorola the A-bis interface is internal for the BTS.
    Motorola also support VSAT connection to the BSC.

    #46850 Reply
    Da Architect,
    Guest

    So here I am again in this topic, where I am obliged to ask again about the High SDCCH assignment failure in alcatel abis over VSAT (50%), is ericsson abis over VSAT face same problem of High SDCCH assignment failure?

    Is it still normal to have high SDCCH Assignment Failures in Alcatel for Abis over VSAT sites?

    #46851 Reply
    pix
    Guest

    Da architect,

    YES it is normal in alcatel systems 🙂 it has been fully documented & described in alcatel database. It is normal + it doesn’t impact the subscriber.

    #46852 Reply
    Da Architect
    Guest

    I am convinced that it doesn’t effect user. But try to convince the upper management!

    Thanks pix!

    #46853 Reply
    Jack
    Guest

    Can I use the VSAT Link like…

    BSC-1 Point to Mulitpoint BTS Connectivity.

    Rgds

Viewing 15 posts - 1 through 15 (of 17 total)
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