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Queuing

Viewing 15 posts - 1 through 15 (of 17 total)
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  • #56147 Reply
    Rex
    Guest

    Hi,
    why in come cells queuing is working and in some not. At BSC level queuing it is activated. What could be wrong. Alcatel equipment, B9 release.

    #56148 Reply
    Pix
    Guest

    Queueing is working only if there is a need to queue tch request = only if the cell is fully occupied.

    Now, if there is TCH NA Congestion Rate > 0% and nuber of queued request = 0, there is a problem.

    So then…

    The maximum number of TCH queued in the whole BSC = 64. Perhaps you should reduce the queue size in the cells, so that the “64” can be equally shared among all cells.
    I forgot the name of the parameter (Q_SIZE ?), what’s its value ?

    Play soft with this parameter, don’t change it too much at a time.

    Regards,
    Pix

    #56149 Reply
    Rex
    Guest

    Thanks Pix,
    the queuing length for the cell is 6. “The maximum number of TCH queued in the whole BSC” I didn’t see among parameters. It’s probably internal BSC value or DLS parameter, isn’t it, maybe I’m wrong? Do you remember the pb with high Inc_HO_Congestion with the cells with no assignment_congestion? Those cells never made any queuing. Probably that all HO relations are in the same BSC or something else (free resources-no queuing). I can’t find the solution. Any way thanks a lot again. I like this forum.
    Regards,
    Rex.

    #56150 Reply
    Pix
    Guest

    The value 64 is a BSC limitation (at least for 9120 G2 BSC, i don’t know for the new 9130 Mx BSC)

    An incoming HO request is not put in a queue, the TCH is either available or not at the time the request is received by the RAM (resource alloc management function in BSC).
    The queue is only available for call setup (= normal assignment).

    If you want to book some TCH for incoming HO, you can do it. There are two parameters (or three?) to do so, per cell. I let you find them out 🙂
    Then I can explain how they work (i need my document to remember.. will get it on monday)

    Cheers,
    Pix

    #56151 Reply
    Rex
    Guest

    Is the parameter N_TCH_HO one of those three params?

    #56152 Reply
    Pix
    Guest

    Yes, N TCH HO will book timeslots for handovers, but it works in relation with ALLOC ANYWAY (i think !).

    I forgot to check today, but if you look at the parameters definition, you might get some clue.

    #56153 Reply
    Rex
    Guest

    I tried changning N-TCH_HO, nothing happens, Inc_HO_cong still remains high. Could TFO(Tandem Free Operation) cause such a pb? It’s activated in all cells of the Network. AMR also.

    #56154 Reply
    Pix
    Guest

    Hi Rex,

    mmm.. ok, a lot of questions :

    Can you check whether the inc ho congestion occurs for intra-HO or intercell HO ?

    In which cell does this occur (band, type, neighbors, coverage, multiband, concentric..? any thing particular ?)

    how many HO inc requests ? how many TCH NA requests ? RTCH Duration average per TRX ? path balance average per TRX ? Erlang FR TCH per TRX ?

    what is the neigbor cell that generates so many HO (check the adjacencies indicators) ? what is the main cause of HO in this neighbor cell ?

    #56155 Reply
    Rex
    Guest

    Hi Pix,
    1. Inc HO Congestion occurs only for intercell HO, intracell HO is disabled in all cells because we had to much congestion and we had to disable it.
    2. Coverage is fine, no multiband, no concentric,single cell, band 900MHz, 26 relations with cells around area. I’ve deleted some today with less requests towards the cell with high Inc_HO_cong and low NA_cong.
    3. there is no cell that generates so many HO, there are free enough resources and HO_inc_cong is high. I can’t understand why. Main cause of HO in neighbour cells is usual PBGT.
    Regards,
    Rex

    #56156 Reply
    Pix
    Guest

    Thx fr the precise answer. You forgot these ones though:
    RTCH Duration average per TRX ? path balance average per TRX ? Erlang FR TCH per TRX ?

    Those values will tell if there is some ping pong ho.

    what is the value of HO MArgin (per adj) ?
    what about en_trafic_ho (per adj) ?
    what about MS TXPWR MAX in each cell ? and BS_TXPWR_MAX (not sure about the name… it’s the BTS power attenuation) ?

    Cheers,
    Pix

    #56157 Reply
    Rex
    Guest

    Hi Pix,
    the problematic cell has 4 TRX. So,
    1. Path Balance=0,5,6,5
    2. RTCH_avg_duration=1s,50s,21s,37s
    3.Traffic=0 Erl,0.1 Erl,2.2 Erl,6.5Erl

    4. HO Margin=5 dB for all relations
    5. En_Traffic_HO=Disabled
    6. MS_TXPWR_MAX= 33 dBm for all
    7. BS_TXPWR_MAX= -2 dB the other cells in relations=0 dB

    I disabled TFO, Inc_HO_cong has been reduced from 20% to 6%, but I have to see off during the whole day.
    Regards,
    Rex

    #56158 Reply
    Pix
    Guest

    Ref,

    Ok, if i can think about it i’ll check with tac why TFO has such an impact on ho inc congestion, in B9.

    what are your parameter settings for TFO ? (there are 4 or 5 TFO parameters)

    #56159 Reply
    Rex
    Guest

    Hi Pix,
    here are parameters as declared in OMC-R for TFO feature for the cell with high Inc_HO_Cong
    EN_TFO=ENABLE
    EN_TFO_MATCH=DISABLE
    EN_TFO_OPT=DISABLE
    FORCE_TFO_HR_WHEN_LOADED=TFO HR preferred
    FORCE_TFO_VS_AMR=DISABLE
    KEEP_CODEC_HO=try to maintain codec for TFO calls only

    There is no TRX declared as Half Rate. I think maybe the pb was for incomming calls wich were half rate, force_tfo_hr_when_loaded is tfo_hr_preferred, then, en_tfo_match is disable, so, from hr to fr couldn’t match the codec and somehow it is counted as congestion. After I disabled TFO (en_tfo=disable) the congestion was decreased. But still not sure that tfo caused all this, it should be failure, not congestion. Thnx.
    Regards,
    Rex

    #56160 Reply
    Pix
    Guest

    Rex,

    your analysis makes sense, i’ll give it a look in the fault databases. (if i have time…)

    #56161 Reply
    Rex
    Guest

    Hi Pix,
    how can I get the fault databases? I apreciate if you can send it to my e-mail rexhepsherifi@gmail.com
    Thanks.
    Regards,
    Rex.

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