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TBF Establishment Failure Rate :

KP - 27th May 2013  (12:46 GMT)


Please check the IMM ASS message and verify whether correct information was sent to the MS.

Check the Radio condition


Agha - 25th May 2013  (04:23 GMT)

Hi ouchfa,
Please share analysis/results..

pix - 21st May 2013  (18:38 GMT)

- try allocating your PDCH on another TRX than the one it is currently using. (the idea is to swap TCH and PDCH, so you can check TCH quality where there were previously the PDCH.)

ouchfa - 21st May 2013  (13:34 GMT)

no respnse from MS caused by:
- Invalid assignment (no valid RLC/MAC block)
- cell change or radio failure
- timer expiry befor MS response

And exist other reasans which i'm working to find it

Best Regards

ouchfa - 20th May 2013  (13:54 GMT)

hi KP;

No BB hopping, just one TRX is dedicated for EDGE (SW installed) so no BB hopping for the concerned EDGE users.

Best Regards

ouchfa - 20th May 2013  (13:52 GMT)

Hi Pix, Thanks for reply;

Number of Attempts:

Number of estab_Failure:
TBFEstFailNoReactUL = SUCPDASA [1..4] - SULACCEL[1..4]
TBFEstFailNoReacDL = SUCPDASA [5..7] - SULACCEL[5..7]

Number of estab_Success:


Problem: high difference between SUCPDASA & SULACCEL which increase Fail due to no reaction from MS.
SUCPDASA:Number of successful PDCH assignments
(uplink/downlink) per cell
SULACCEL:Number of successful PDCH seizures (uplink/downlink)per cell

UL_Succ_Rate < 60% till 20%
DL_Succ_Rate >=85%

No interferance is detected and Fail due to no reaction remains all the time.

Rx_Access_min = 6 -> -105 dB
(Alpha,Gam) = (0,0)
Init_MCS = MCS1

I changed T3168 from 1s to 2s, (waiting for remark after 2 or 3 days)

Thanks/ Best Regards

KP - 20th May 2013  (12:15 GMT)

Is the TBF failure ratio is increased after enabling the BB hopping?

pix - 19th May 2013  (18:59 GMT)

hi Ouchfa,

Are you having failure due to No Response, or something else ?

Could you give an exemple of the TBF failure %, hourly, over 24hours ? (the % , but also, the numerator + denominator of the formula)

Please post the UL failure % and the DL failure % separately.

Radio failures should normally be caused by interference :
- try allocating your PDCH on another TRX than the one it is currently using. (the idea is to swap TCH and PDCH, so you can check TCH quality where there were previously the PDCH.)
- ensure your UL GPRS Power Control is disabled. (look for gamma and alpha values) - (Edit : you said you did disable it already.)
- ensure your rx access min is not set too low
- ensure your path balance is ... balanced :)


ouchfa - 19th May 2013  (12:53 GMT)

hi Agha, thanks for your reply :)
I have already deactivate PC, and changed INIT_GMSK_MCS and INIT_8PSK_MCS to MCS1, but no improvment.
I was thinking to increase T3168 to give more time for users in UL (What do you say?)
ok I'll check points listed in your coment.

Agha - 18th May 2013  (05:09 GMT)

Also check Transmission performance KPI's(TRAU Error Rate).

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