AMR 2G Problem

[RF engineer]

yes it is

Br

Josef

So in your case you have to do some optimization tasks in order to reduce handover and later make drive test you see some improvement to use higher or lower codecs

[josef]

So in your case you have to do some optimization tasks in order to reduce handover and later make drive test you see some improvement to use higher or lower codecs

We can't start optimization in our situation.

I explain again, our situation is:

- in 90% of the cells, MS comp on 5.9 codec (on call setup or HO) and it is not changing even if C/I > 25 dB
- in 10% of the cells, MS comp on 5.9 codec and start to upgrade or downgrade basing on radio conditions (C/I level): normal behaviour

NB.

* All cells have same parameters,
* Thresholds for full rate: 6, 9 and 12 dB
* Thresholds for half rate: 11 & 14 dB
* Working cells can be: DCS or GSM 900; Half rate or Full rate

I'm waiting for your help brothers

Josef

[RF engineer]

We can't start optimization in our situation.

I explain again, our situation is:

- in 90% of the cells, MS comp on 5.9 codec (on call setup or HO) and it is not changing even if C/I > 25 dB
- in 10% of the cells, MS comp on 5.9 codec and start to upgrade or downgrade basing on radio conditions (C/I level): normal behaviour

NB.

* All cells have same parameters,
* Thresholds for full rate: 6, 9 and 12 dB
* Thresholds for half rate: 11 & 14 dB
* Working cells can be: DCS or GSM 900; Half rate or Full rate

I'm waiting for your help brothers

Josef

Yes this 90% is come majority from handover if you don't reduce handover from cells overshooting you will not have any improvement so it is your decision what to do i am not sure any radio parameter can be help to reduce this rate.
BR
RF

[josef]

Yes this 90% is come majority from handover if you don't reduce handover from cells overshooting you will not have any improvement so it is your decision what to do i am not sure any radio parameter can be help to reduce this rate.
BR
RF

It is not related to handovers. When MS comp on one cell and with all the values that you can imagine of C/I we have THE SAME codec (initial one).

That means that AMR algorithm is not working.

Example: We suppose that we have only full rate. when MS comp on one codec (by starting call or by handover), it will choose the initial code (for us 5.9 Kbps), and it will start to measure C/I. if it measure for example 20 dB, then as our thresholds are FRT1= 6 dB, FRT2= 9 dB, FRT3= 12 dB

ie C/I > FRT1 + Hyst1 (1dB)> FRT2 + Hyst2 (1dB)> FRT1 + Hyst3 (1dB)

MS must upgrade to 7.4 Kbps and then to 12.2 Kbps

If this is not working no need to optimize anything. the problem is not related to parameters

It is related to something that I don't know

Any help ?

Regards,
Josef

[ayman.absi]

Choose one of the cells that the AMR reconfiguration not working and do Drive test stationary (without moving).
Another check AMR license (No. of TRXs that could use AMR) if Total no. of TRXs per BSC > license --> you will have some TRXs not using AMR.

[josef]

Choose one of the cells that the AMR reconfiguration not working and do Drive test stationary (without moving).
Another check AMR license (No. of TRXs that could use AMR) if Total no. of TRXs per BSC > license --> you will have some TRXs not using AMR.

Dear Ayman,

For one BSC this is the features activated.
FEATURE INFORMATION:
----------------------------------------------
FEATURE CODE:..............73
FEATURE NAME:..............Flexi EDGE BTS Operating SW
FEATURE STATE:.............ON
FEATURE CAPACITY:..........1568
----------------------------------------------
FEATURE CODE:..............74
FEATURE NAME:..............High capa BSC3i new
FEATURE STATE:.............ON
FEATURE CAPACITY:..........2000
----------------------------------------------
FEATURE CODE:..............13
FEATURE NAME:..............PCU2 app SW
FEATURE STATE:.............ON
FEATURE CAPACITY:..........100
----------------------------------------------
FEATURE CODE:..............4
FEATURE NAME:..............EDGE BSS Fnc
FEATURE STATE:.............ON
FEATURE CAPACITY:..........1400
----------------------------------------------
FEATURE CODE:..............1
FEATURE NAME:..............AMR Capacity
FEATURE STATE:.............ON
FEATURE CAPACITY:..........1530

COMMAND EXECUTED

So the feature for AMR is "AMR capacity" or no? the number 1530 is it the number of TRXs where we can have AMR feature?

Thank you by advance,

Josef

[ayman.absi]

Dear Josef,
Feature Code = 1 is for AMR HR and it is enabled.
What about AMR FR (Feature Code = 72)?
If it is not enabled --> AMR HR will not work in cells with low Traffic.

Thanks,

[josef]

Dear Josef,
Feature Code = 1 is for AMR HR and it is enabled.
What about AMR FR (Feature Code = 72)?
If it is not enabled --> AMR HR will not work in cells with low Traffic.

Thanks,

I have in some cells a normal behaviour with FR mode (starting with initil codec 5.9 and going to 12.2 Kbps). I think that the feature is enabled. No?

[josef]

Dear all,

is it possible during implementation that: when we mixe some PCMs between Radio part and Core part, we will have this kind of problem

Thank you by advance.

Josef

[josef]

Dear community,

We still have the same problem. We discover that the problem is random: for example even in stationary mode sometimes it is working (I mean codec upgrade) and sometimes the initial codec is kept. I check even in timeslot level and the problem is the same: sometimes Ok sometimes NO

We check parameters in radio part and we check also in core part and we couldn't find anything !!

licenses are ok for AMR hr and fr

From where can come this problem?

Your help is really needed

Thank you by advance

Josef