VoNR Standards

3GPP specification baseline

Specification	Title	VoNR relevance
TS 23.501	System Architecture for 5G System (5GS)	Core 5G SA architecture – AMF, SMF, UPF, PCF, UDM, AUSF and their interfaces. The 5G equivalent of TS 23.401 for LTE.
TS 23.502	Procedures for 5G System	5G SA call procedures including PDU session establishment, QoS flow setup for VoNR, EPS fallback procedures.
TS 23.228	IP Multimedia Subsystem (IMS) stage 2	Core IMS architecture – identical to VoLTE. P-CSCF, S-CSCF, TAS, HSS. Applies to both VoLTE and VoNR.
TS 24.229	IP multimedia call control based on SIP and SDP	SIP/SDP procedures for VoNR call setup. VoNR-specific additions in Release 15 and later.
TS 26.441	Codec for Enhanced Voice Services (EVS); General overview	EVS codec specification. Defines narrowband, wideband, super-wideband, and fullband modes and bit rates.
TS 26.445	EVS codec detailed algorithmic description	Full EVS encoder and decoder specification.
TS 38.331	NR Radio Resource Control (RRC)	5G NR RRC procedures including bearer/flow setup for VoNR.
TS 23.167	IP Multimedia Subsystem (IMS) emergency sessions	Emergency call handling for VoNR – 112 over 5G SA IMS.

GSMA profiles for 5G voice

The GSMA produces interoperability profiles for IMS voice equivalent to IR.92 (which governs VoLTE). The 5G voice equivalent ensures that VoNR implementations from different operators and device manufacturers interwork correctly. GSMA engagement with 5G SA voice interoperability has accelerated as operator deployments increase.

3GPP Release timeline for VoNR

Release	Date	Key VoNR additions
Release 15	June 2018	VoNR baseline – 5G SA architecture, basic IMS over 5G SA, EPS fallback, QoS flows with 5QI
Release 16	July 2020	Enhanced VoNR – network slicing improvements, IMS data channel, enhanced EPS fallback
Release 17	June 2022	Multimedia Telephony (MMTEL) enhancements, 5G SA emergency services improvements
Release 18 (5G-Advanced)	2024	AI/ML for voice quality, further URLLC-voice integration, enhanced EVS over 5G