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I have a strange case of SDCCH and TCH blocking in a site with one TRX(Omni site).Uprades has been done but the problem persist.Please assist me.Thank you.
sdcch congestion is
when
signaling problems,location update failures,poor location area planning,vlr overload, c7 overload
tch congestion:perhaps you have not enough adjacent or bad adjacent or maybe you have none optimal parametr for handover or rf power
DR PARAMETR CAN HELP YOU FOR TCH CONGESTION
BEST REGARD
hk3912YAHOO.COM1)decrease TRX Tx power,reduce cell coverage
2)or expansion to two TRX,increase SDCCH & TCH.1)decrease TRX Tx power,reduce cell coverage
2)or expansion to two TRX,increase SDCCH & TCH.Thanx a lot.
Hamid ,please tell me what is the DR PARAMETER that you mentioned in your reply above.
I wonder if I can send you the little extract of the concerned cell, may be you can figure out for me what the problem is.Hi muzi
I happy if i can help youDirected retry(DR) is a procedure which is used in a call set-up phase when a mobile station is assigned to a traffic channel in a cell other than the serving cell in situations of congestion.
Directed retry procedure is an optional feature.
When the directed retry procedure is initiated, the following two timers control the creation procedure for a handover candidate cell list.
·It is possible to determine the period starting from the assignment request during which the directed retry is not allowed. The BSC can start the target cell evaluation for the DR handover after the time supervision has expired. This period is allowed for the mobile station to decode the base station identity code (BSIC) of the adjacent cells before the target cell evaluation. The time supervision is controlled on a cell-by-cell basis with the parameter MinTimeLimitDR.
·The BSC can continue the target cell evaluation for the DR handover until the maximum time allowed for the start of the DR handover expires. The time supervision is controlled on a cell-by-cell basis with the parameter MaxTimeLimitDR.
When the directed retry procedure is initiated, the directed retry threshold method can be taken into use. The following two parameters control the directed retry threshold method.
·The directed retry threshold method makes it possible to use RX signal level of the adjacent cell in the candidate cell list creation procedure. The directed retry threshold method is controlled on a cell-by-cell basis with the parameter DRMethod.
·The directed retry threshold method determination is based on the predefined minimum threshold value of RX signal level. The directed retry threshold is controlled on a cell-by-cell basis with the parameter DRThreshold.Direct Retry issue—
1.Is it possible to activate the DR PARAMETER when you have only one TRX?
2.I saw one incident which makes sense because the cell is busy(high call volume,close to congestion)where we added another trx(capacity),the second SDCCH and activated direct retry.This causes confusion because the initial matter=site with LOW call volume,but it is congesting
3.What causes “outgoing intra-cell bsc handopver success rate” poor on two adjacent cells of the same site,e.g.sector1&2.=what could be wrong in this issue.Notw!!!
Point #3 is not related to the 2 above.
Errata:-it should read “Outgoing Intra-Bsc handover success rate”.hi
1-yes,it is possible to activate the DR PARAMETER when you have one TRX or more because DR is inter cells(between adjacents in call setup)
2- when DR is used quality decrease due to ms connect to far bts (near bts have congestion and its adjacent has lower power&quality )
3-i donot understand well
good luckThank you very much.
We tried your suggestion first and the problem is solved.
We added the another TRX and SD.Tata.
There is another query I’ve got now.
You guys are enloghtning my mind with your experience.1.I’ve got two bts’s(bts01&02) which looks like they are overlapping in the same building where they are serving,but they are at a very bad levels(loose coverage completely.)
2.The other issue is that,in the entrance of the building I pick cell02,bts01 which is directly facing the building.In the inside I pick cell01,bts01.Walking around the stairs just 7m walk in the passage I get the handover to bts02
It looks like swapped sectors.what is the formula to calculate the SDCCH time congestion and TCH time congestion . Results should be in seconds not in percentage.
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