. Summary In this chapter, we have seen the various procedures in 5G and how they come together to service a subscriber. We have gone over how a PDU session is established in 5G, and we have gone over how to connect a 4G radio to work with a 5G interworking function. We have seen how to establish a voice call over New Radio and finally, we have seen how Wi-Fi access integrates with a 5G system. By the end of this chapter, we now understand the 5G call flows in detail and have developed a near-practical understanding of the messages exchanged between the various network functions to bring about a data or a voice call in 5G. In the upcoming chapters, we will delve further into 5G-NSA and 5G-SA system architectures that leverage these procedures. The next chapter introduces exclusive VoNR concepts. Voice over New Radio (VoNR) The combination of Voice over Long-Term Evolution (VoLTE) and Voice over NR (VoNR) will be the long-term voice infrastructure for mobile service providers. In this chapter, we will discuss the main concepts behind future VoNR networks. Furthermore, VoNR will be analyzed from end to end with a focus on the architecture requirements, initial procedures, call establishment, and interworking. VoNR has got some very close similarities to VoLTE. For example, both technologies require an IP Multimedia Subsystem (IMS) for call signaling, and both technologies employ their Radio Access Network (RAN), transport, and core networks to carry voice media in the form of IP packets. We'll go through the following topics in this chapter: VoNR concepts and drivers VoNR high-level architecture VoNR initial procedures VoNR call procedures Interworking and voice call continuity VoNR concepts and drivers In this section, the concepts and drivers associated with VoNR are analyzed in three main areas: IMS network deployment growth, 5G system service requirements, and ultra-high-definition audio. IMS network deployments growth The number of subscribers associated with packet voice services over telephony such as VoLTE 