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Hi friends,
I am experiencing high SDCCH congestion in most of cells even if the SD Traffic is low than the capacity, this is causing a decrease of Immediate Assignement Success Rate which affect the CSSR… This is a Siemens network. Any help will be appreciated…Hi Planet,
Check Timer setting and RACHBT setting. I am affraid this is overshooting site so this site is over hearing for any RACH. Checkn if any HW failures. Try to swith the BCCH TRX to any TRX
ThanksHi Planet,
Thank you for your fast replay, I check the RACHBT
setting and is Ok, most of sites have tilt of antennas
as -6, so that’s whay I exclude the overshooting cause
because most of sites are sufering from the same
problem ( congestion high even if the capacity is more
ok), it remains the Timers setting which I daubt too
as you said,do you have any idea about the famous
Timers that may affect the QoS when are not good set.
ThanksHave you checked if the transmission line (MW, leased line) is ok?
Maybe it´s oscillating in some moments and this can make your sub-TS´s on the ABIS unavaiable…Hi Fabio,
Thanks a lot for your clarrification, you are right concerning the unavailable TS on the Abis interface because I asked for Alarm report on cells in the OMC and most of them having LAPD Signalling overload ( may be caused by link instable), I reduce Timer T3101 from HLFSEC-6 to HLFSEC-3 to minimise the effect of Fantom RACH and the blocking is minimised but still high in some cells even if the capacity is OK, so what should I do to solve problem of overload on the LAPD (ABIS)?
thanks in advancePlanet,
Have you tried to create another LAPDm link? Sometimes, if you have a large number of TRX in this pool, it´s necessary to create another signalling link.
Hi,
By congestion do you mean blocked attempts or “percentage of time when no free SDCCH channels were available”
Thanks to All,
to Vanderlay: Yes I mean blocked attempts, the other one is not used in SDCCH dimensionning because it gives you the utilization of the ressources.
to Fabio: I didn’t tried to add more LAPDm link on the Abis because the number of TRX’s in the BTSM not exceed 14, when this happend people in NOC add second Abis with another LAPDm link..do you have any idea about maximum number of TRX’s supported by one LAPDm TS for signaling in the Abis interface?
thanks in advanceHi Planet,
There’s no a number of TRX can be handling by one TS LAPD.
For your case try to add other LAPD TS and assigne some TRXs to the first LPDLM and the others to the secand by the parameter LPDLMN in Create TRX object.
and let’s us know the effects.
Thanks
Planet,
You´re correct about the theoretical limit of 14 TRX…
Although you may experience some problems (like the one you´re having)and in this case, I really think it´s a good idea to try to create another LPLDM link and associate some TRX with this new link.
I think this could solve your problem.Try it out and make us know the results.
Dears,
Thanks a lot for the idea.. OK I will try it and update u by the result
ThanksHi, How can I calculate succes rate for NB_LAPD_INFO_FRAME on both RECEIVE AND SENT
Please do describe clearly.
sdcch congestion
Hi
Can you plz explain HLFSEC-6.
I mean what does this 6 mean as well as hlfsec ???Waiting for reply.
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