VoNR high-level architecture
There are three main components associated with the VoNR architecture. These are the 5G New Radio (NR) access network, 5G core network (5GC), and IP multimedia subsystem.
5G NR access and core networks
5G NR access and core networks transport call signaling and voice packets.
Call signaling is performed as a Session Initiation Protocol (SIP). SIP is the control signaling used between the device and the IMS to initiate, maintain, and terminate real-time applications such as voice, video, and messaging. From a Quality of Service (QoS) perspective, it is critical that signaling cannot be delayed or dropped. In VoNR, SIP is transported through the 5G system, and the 5G system is responsible for meeting the necessary QoS requirements.
Once the call is initiated, associated voice packets are carried by the 5G system in the form of a Real-time Transport Protocol (RTP). It is possible to drop some voice packets without degrading the call quality. However...