Does UE having no VoLTE capability can send "IMS preferred" during network attach procedure?

Dear collegues, just a short question:
Does UE having no VoLTE capability can anyhow send “IMS preffered” in voice domain preference IE during network attach procedure?
My inderstanding is that it must be ready for VoLTE from SW perspective also not just from HW perspective.

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You can check parallely FGI bit 3 and 7 that need to be 1 supported.
If not UE can’t support VoLTE.

Any idea how to check VoNR capability of device?

Mobile device? Or BS?

For mobile device in the UE capabilities we have a parameter.

voiceOverMCGBearer
Indicates whether the UE supports IMS voice over NR PDCP for MCG bearer in NR. It is mandated to the IMS voice capable UE in NR otherwise optional.

:+1: thanks will check that.

Please tell is it for VoLTE support in NSA for LTE leg?
VoNR for SA option 2 where only 1 cell group capability to be different.
Please correct me if wrong.

Thank you.
My Understanding is if UE has these 2 FGIs set to 1 that means chipset is VoLTE ready but it does not mean UE can handle VoLTE by default.
To be able to handle VoLTE device vendor needs to provide also Firmware with operator specific IMS APN and unlock volte on SW level.
I want to count UEs in my network by using Anritsu eoLive tracing systen and idea is to count not UEs having HW Readyness but also SW readiness.
I am interested to link SW readiness and signaling message.
My thought is that I can do so via using voice domain prefference bits in EMM attach message.
But I am not sure is that correct way.

Yes correct.
Binary required for VoLTE over device once device is new in market for testing.
Once device commercialized and VoLTE network live then its by default in device from factory.

Yes that’s correct.
If you have SA mode option 2 than there is an entire set of parameters for VoNR.

voiceOverEUTRA-5GC:
Indicates whether the UE supports IMS voice over E-UTRA via 5GC. It is mandated to the UE if the UE is capable of IMS voice over E-UTRA via 5GC. Otherwise, the UE does not include this field. If this field is included and the UE is capable of E-UTRA with EPC, the UE shall support IMS voice over E-UTRA via EPC.

voiceOverNR:
Indicates whether the UE supports IMS voice over NR. It is mandated to the UE if the UE is capable of IMS voice over NR. Otherwise, the UE does not include this field. If this field is included and the UE is capable of E-UTRA with EPC, the UE shall support IMS voice over E-UTRA via EPC.

voiceOverSCG-BearerEUTRA-5GC:
Indicates whether the UE supports IMS voice over SCG bearer of NE-DC.

Other than that a UE needs to support RoHC profile 0,1 and 2 as well.

Yes, I believe that its the firmware that unlocks the UE’s hardware to make it VoLTE capable.
I have seen that practically when I bought a new phone that the vendor said it supported Volte but that was not showing Volte.
After some SW release, it started showing Volte.

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