Rate control for VoLTE

Hi Experts,
Question: why MNOs are against rate control for VoLTE?
This would improve a lot the quality of voice calls (MOS score).

Maybe don’t want to purchase high codec like EVS which include semi wide band and full band.
Costly as this will give crystal clear voice.

EVS is up to 128 Kbpsec.
Crystal clear concert quality.
But I am speaking even about AMR-WB.
Why they don’t enable rate control?

Are you talking about VoLTE rate control feature in AMR-WB?

There are 9 codecs for Voice.

It should be enable.
MOS will improve may be utilisation goes a bit high.

Just check in your network and you will see it is not enabled.
Most operators go plainly with 12.2 Kbpsec.

Most of have not enabled but it should be because this will help MOS.
Voice quality.

Here is a table with MOS score per rate:


Mos will improve if we use codec like wideband and so on.
Like wise they should have this supported at their hardware and license end both.
Mostly operators have.
And as per Huawei if VoLTE users are greater than 5 percent of users and Dl and UL packet loss is more than 1 percent then they enable it if both hardware and license available; I don’t know why this thumbrule given.
With cce criteria too.

I see some VoLTE log files with many codec rate, not only 12.2.

It depends on operator but most operators have it disabled.
In the countrie I checked almost all MNOs have enabled EVS that is 128 Kbpsec.
That requires a lot of capacity, but provides top-notch quality.
But now they have 5G to offload so there’s no more capacity concern as it used to be.

EVS is having many issues with ECO system then core and SIP encryption setting.
We did many testing with handset vendors and decide to enable EVS but without rate control.
It’s taking high capacity on radio but no major risk of call drop which involve with rate control.
So its static EVS codec and no further modification once assigned.

Updated tables for AMR and EVS voice coding rates:

Heelo Experts.

Can anyone share experience on this (VoLTE Rate Control)?