- This topic has 16 replies, 1 voice, and was last updated 11 years, 7 months ago by Rex.
6th March 2009 at 12:56 #56147RexGuest
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.6th March 2009 at 23:12 #56148PixGuest
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.
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.
Pix8th March 2009 at 18:55 #56149RexGuest
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.
Rex.8th March 2009 at 19:00 #56150PixGuest
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)
Pix8th March 2009 at 21:36 #56151RexGuest
Is the parameter N_TCH_HO one of those three params?9th March 2009 at 20:20 #56152PixGuest
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.11th March 2009 at 14:08 #56153RexGuest
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.11th March 2009 at 18:00 #56154PixGuest
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 ?11th March 2009 at 22:15 #56155RexGuest
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.
Rex12th March 2009 at 06:37 #56156PixGuest
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) ?
Pix12th March 2009 at 11:24 #56157RexGuest
the problematic cell has 4 TRX. So,
1. Path Balance=0,5,6,5
3.Traffic=0 Erl,0.1 Erl,2.2 Erl,6.5Erl
4. HO Margin=5 dB for all relations
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.
Rex12th March 2009 at 18:41 #56158PixGuest
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)13th March 2009 at 15:35 #56159RexGuest
here are parameters as declared in OMC-R for TFO feature for the cell with high Inc_HO_Cong
FORCE_TFO_HR_WHEN_LOADED=TFO HR preferred
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.
Rex13th March 2009 at 18:20 #56160PixGuest
your analysis makes sense, i’ll give it a look in the fault databases. (if i have time…)14th March 2009 at 23:07 #56161RexGuest
how can I get the fault databases? I apreciate if you can send it to my e-mail firstname.lastname@example.org