Halfrate statistics are stepped when half-rate not active/passive(for CU new KPI)

Halfrate statistics are stepped when half-rate not active/passive.(for CU new KPI)

For the CU new KPI()ib bad .TCH congestion Rate=( CELTCHF:TFCONGSHO + CELTCHH:THCONGSHO + CELTCHFP:TFESTPGSMSUB) /(CELTCHF:TFCALLS CELTCHH:THCALLS)DATEPERIODBSCTFCONGSHOTHCONGSHOTFESTPGSM1TFCALLSTHCALLS

0703261900-2000B21*R12/GAP/0/0/02/19M114945981499697383960.0213HR

0703261900-2000B22*R12/GAP/0/0/02/19M138611449480101598133560.0504HR

0703261900-2000ESBSC2R10/GB/0/0/04/2454705616588000.0168

0703261900-2000ESBSCR10/GB/0/0/04/24438040710296900.0082

0703261900-2000EZBSCR10/GB/0/0/04/241782750555751328170.0429

0703261900-2000HGBSC2R10/GAP/0/0/07/45286208982640913530.0213

0703261900-2000HGBSCR10/GB/0/0/04/24422183573052912700.0208

0703261900-2000HSBSCR12/GB/0/0/01/14205005837100.0035

0703261900-2000JMBSCR12/GB/0/0/01/141246496012741134850.0133

0703261900-2000JZBSC2R10/GB/0/0/04/245046404529615150.0029

0703261900-2000JZBSC3/A33CA/0/0/07/45133120425852117770.0049

0703261900-2000JZBSCR12/GB/0/0/01/14161108010548372810.0024HR

0703261900-2000SZBSCR10/GB/0/0/04/246552642026226727030.0173

0703261900-2000XFBSC2R12/GAP/0/0/01/14307005670900.0054

0703261900-2000XFBSCR10/GB/0/0/04/241026039014574100.0097

0703261900-2000XGBSC2R10/GAP/0/0/07/456752811735233325380.0206

0703261900-2000XGBSCR10/GB/0/0/04/2411224571778447833550.0200

0703261900-2000XNBSC1R10/GB/0/0/04/244081611115089818100.0129

0703261900-2000XTBSCR12/GB/0/0/01/141867508960527000.0028

0703261900-2000YCBSC2R10/GAP/0/0/07/4558402407495600.0110

0703261900-2000YCBSCR12/GB/0/0/01/146594300120620140670.0081HR

Symptomhalfrate statistics are stepped when half-rate not active/passive

ChangeCustomer deactivated the feature Dynamic halfrate allocation, undefined the halfrate transcoder and deactivated the feature halfrate support in the MSC.Exchange property HALFRATESUPP-0 was not changed.

CauseFirst of all, concerning the de-activation of halfrate support in the MSC.

I still have been unable to find anyone here in the MSC group who knows what the result of this action should be (maybe it disallows TSCs with halfrate values?). Anyway, halfrate is really only a saving on capacity on the BSC and calls are still handled at 64Kbits/s in the MSC.But as we shall see below it will not matter what the setting is in the MSC for our case. As stated in TR AF67764, the only way to ensure that halfrate is not used in the BSC is to set HALFRATESUPP-1.

The behaviour that you have seen has been in cells that have had high traffic and congestion and has increased the counters

CTHCALLS (H'232) for halfrate allocation attempts THCONGSAS (h'234) for HR congestion at assignment THCONGSHO (h'236) for HR congestion at handover CTHMSESTB (h'24A) for MS establishments on HR TCHs.

We were concentrating our investigation on when a HR timeslot is seized as a traffic channel and there are explainations as to why the block RNLCT would attempt to seize a halfrate channel for a dualrate mobile when all fullrate channels are congested. This easily explains the attempt and congestion counters, but the mystery is the MS establishment counter increase, especially if there is no HR transcoder pool available??

IF we consider a cell with all SDCCH channels congested and also noting that your customer has the CHAP set to 1. This means at immediate assignment when the dualrate mobile requests a signalling channel and none is available then the BSC will allocate a TCH in that cell to be used first as a signalling channel and then later modified to a traffic channel. As stated in the user description for "Immediate assignment on TCH" , section 2.1, situation 2 "The first attempt is to allocate a TCH halfrate if dual rate capability is indicated". Remember that there has been no signalling with the MSC until now, a transcoder is not needed for a signalling channel and since HALFRATESUPP-0 all cells have halfrate channels available.

The HR channel is allocated for signalling and when the SCCP Connection Confirm message returns from the MSC the MS establishment counter for HR will be stepped.

If it tries to modify this TCH to carry traffic it will also succeed (unless no HR pool is available - then the congestion counters are stepped).

SOLUTION:The only way to prevent all halfrate call attempts in a BSC (and hence all halfrate statistic counter increments) is to set halfratesupp-1 using RAEPC.

Then an initial load or reload needs to be done to re-configure all cells.

A small or large restart will not suffice. Halted and activating each cell is also a possibility.