- This topic has 16 replies, 1 voice, and was last updated 12 years, 1 month ago by Pravesh.
15th March 2007 at 07:39 #46839SamGuest
We have high delay in call setup for a VSAT site.What could be the issue and what’s the resolution.15th March 2007 at 10:20 #46840PixGuest
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.17th March 2007 at 04:55 #46841SAMGuest
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 reason17th March 2007 at 10:03 #46842PixGuest
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.. (??)19th March 2007 at 12:06 #46843SamGuest
The AMR traffic is detected in the Uplink traffic (from the BTS side).Then how could it be transcoder or switch.19th March 2007 at 16:24 #46844PixGuest
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 ?22nd March 2007 at 06:10 #46845Da ArchitectGuest
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,22nd March 2007 at 13:01 #46846PixGuest
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 🙂
pix7th August 2007 at 15:22 #46847JackGuest
Anybody implemented ..Abis over VSAT for E/// BSC and BTS ?7th August 2007 at 18:32 #46848JohnGuest
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.7th August 2007 at 19:38 #46849KumaGuest
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.8th August 2007 at 06:41 #46850Da 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?8th August 2007 at 07:11 #46851pixGuest
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.9th August 2007 at 07:23 #46852Da ArchitectGuest
I am convinced that it doesn’t effect user. But try to convince the upper management!
Thanks pix!9th August 2007 at 09:00 #46853JackGuest
Can I use the VSAT Link like…
BSC-1 Point to Mulitpoint BTS Connectivity.