AMR FR : Huawei solution

[gogotchiya83]

Dear Experts,
We have a problem in our MOS in compared with our competitor, last time we made a DT and we find some strange result, exampl : AMR FR 12.2 Kbps with MOS value less than 1.5 !!!


28369











When we discover that we decided to disable the AMR FR (test made on city: good Rxlev with good Rxqual) and the strangly the MOS become better
How you can explain that ?

[khurrambilal01]

If Intra-Cell Handover is enabled in the network then what is happening is that for bad quality samples BSC is giving a Intra-Cell Handover command to shift that call to AMR FR (To improve user perception) but the problem is if quality was bad on one of the timeslot there are bright chances that it would be bad on other timeslot as well (Even on other TRX),
Once you disabled the AMR FR then no Intracell HO was taking place and the bad quality call was being Handed over to neighor cell which has more probability of having good quality as compared with last serving cell's intra timeslots/TRXs.

So, this indirectly justifies your MOS result (If you have intra cell HO enabled in your network before disabling AMR FR)

[gogotchiya83]

Tkx for your Nice answer, can you share some docs treating this issue?

[gogotchiya83]

Dear experts, Still waiting for you help? As you can see bellow in some area we have bad MOS even with the use of AMR FR 12.2 in good radio condition (C/I > 30)
How you can explain that?
28393

[beniy]

Dear experts, Still waiting for you help? As you can see bellow in some area we have bad MOS even with the use of AMR FR 12.2 in good radio condition (C/I > 30)
How you can explain that?
28393
My friend,
I think Iknow what is problem,
Just tell me it happened in which BTS type?
you are using A OVER IP or not in your network?

[gogotchiya83]

thanks, i hope that you will be able to help us (for the momemnt we decided to deactivate the AMR FR, and we see a real improvement in our MOS trough the DT and also in the VQI, so we are sure that the problem is comming from the AMR FR).
We use BSC 6900, A over IP...
Any help?

[beniy]

thanks, i hope that you will be able to help us (for the momemnt we decided to deactivate the AMR FR, and we see a real improvement in our MOS trough the DT and also in the VQI, so we are sure that the problem is comming from the AMR FR).
We use BSC 6900, A over IP...
Any help?
My friend,
What is BTS type? this is very important...Mostly problems refer to BTS 312 and some Codec.
ANd please tell me which equipment you done MOS test and analysis.

Answer me we had complete analysis about that and we found the issues

[gogotchiya83]

Tkx beniy for your answer,

We have BTS 3900, we used NEMO for the DT with mobile supporting AMR...
We did many test and we seen an improvement of the MOS after disabling the AMR FR (test done with NEMO, PROBE)...
So no we decided to deactivate this feature in the whole network...

Any help PLZ

[beniy]

We had exact problem please send me your email to send you something.
And please send me MOS TEST before and after deactivating FR AMR.
And tell me you have Just BTS3900? BTS Type is very important.
that's long story There are diffrent problems and I need some statistic to tell you exact problem in your network..
Check your PM

[airian]

We had exact problem please send me your email to send you something.
And please send me MOS TEST before and after deactivating FR AMR.
And tell me you have Just BTS3900? BTS Type is very important.
that's long story There are diffrent problems and I need some statistic to tell you exact problem in your network..
Check your PM

Dear Beniy do share with us too about your analysis plz. will increase our knowledge too.

Dear Gogotchiya we also have an A over IP network of Huawei with BTS3900 and we had done Benchmark with NSN and E******* non A over IP with nemo. the results were great with Huawei AMR. You should involve your vendor in this scenario.

Also plz share your settings for MOS calculation i.e. audio sample size. You can also verify your MOS equipment as MOS values can be very low even with weak battery backup of MOS equipment, wrong loudness settings on MS etc.

[gogotchiya83]

Tkx for your intersting answer,
As i told you we deactivate the AMR FR in one BSC and the MOS become better
For the rest of KPI no major change ...
But we see an improvement in Rxqual 0...5 after this action ....
Any explanation of that phenomena ?

28762

[usama0795]

very interesting case....can u share the traffic distribution after AMR FR was disabled.....i mean HR and FR.....maybe calls got shifted from Lower AMR FR codec to EFR after u disbaled AMR FR just guessing....

[gogotchiya83]

Of course EFR replace the AMR FR with a litte decrease of the HR use !!!
Any help PLZ !!!
28793

[usama0795]

i think the threshold u set for trigerring AMR FR for 12.2kb/s and that for intra-cell-Ho from AMR FR to AMR HR werenot accurate enough thats why improvement in quality; check codec rates dsitribution ....as i did this study since in our network MOS was also quite degraded and based on data accumultaed in Drive Test it showed my operator had underutilized AMR codec 12.2 compared to other operators reason for such a low MOS.......

p.s....MOS that low is not possible with AMR FR 12.2 there is some fault with equipment u tested.....did u use Qvoice??

2880428805

[beniy]

Tkx for your intersting answer,
As i told you we deactivate the AMR FR in one BSC and the MOS become better
For the rest of KPI no major change ...
But we see an improvement in Rxqual 0...5 after this action ....
Any explanation of that phenomena ?

28762
My Friend,
As I told you that's quite normal and every one knows which EFR is better than AMRF in average.
But the case is in very bad quality cases which AMR is better and because of that Operator want to keep AMRF,
Possibly for Inbuilding users with low quality.
28890
If you have good Quality in your BSC keep EFR and if you have dense Urban you can keep AMRF.

2888828889

[gogotchiya83]

I agree with you, the same was seen in our network (see bellow a comparison between : befor and after the deactivation of the AMR FR) :
We have to focus now on the tuning of the AMR ...
Any help PLZ

28931

[nandi_saikat1]

Hi Benie, I am junior member. Seeking help from seniors. Want to improve UL Quality in ZTE 2G system. In India, we don't have MOS KPI. Can we get quality improvement by disabling AMR FR?

[beniy]

Yes,you will get good improvement , But take care about low level area.

[beniy]

gogotchiya83 , what exactly you want to know about AMR setting.?