Mobile voice service continues to play an integral role in the world of mobile wireless communications. 5G Americas’ white paper The Future of Voice in Mobile Wireless Communications provides an update on radio access network evolution and cloud infrastructure evolution for voice services in the 5G ecosystem.
As voice calls have moved from circuit-switched 2G/3G networks to 4G packet-switched Voice-Over-LTE (VoLTE) networks, customers have benefited from new features such as Enhanced Voice Services (EVS) codec-based HD voice, Video calling, and Rich Communication Services (RCS). The emergence of 5G networks is now opening the door to 5G Voice-Over-New-Radio (VoNR), which offers compelling new opportunities to improve call quality, reduction of operational costs for network operators, and faster network technology migration.
The migration path to VoNR offers several challenges to ensure that voice calling is not disrupted for consumers. Most of the wireless industry has been taking a phased approach to introducing 5G into the existing networks, so as 5G networks transition from non-standalone to standalone, an Evolved Packet System Fallback (EPSFB) will be a temporary solution that will eventually lead to full VoNR.
Under non-standalone 5G networks, IP Multimedia Subsystem (IMS) services, including voice calling, will utilize the LTE network without impacting the control plane signaling. When 5G standalone (SA) becomes mature, NSA and SA will coexist in operator’s networks, so will need to interact to ensure existing voice services, including E911 over NR, function properly. Beyond the network architecture, network operators will also have to consider the overall device ecosystem – as well as their existing infrastructure and spectrum allocation – and specific regulatory requirements for their region.