Providing voice service continuity in evolved packet systems

The evolved packet system is being standardized and developed to provide IP-based mobile data services as well as traditional voice service. As voice service is still deemed one of the key EPS services, mobile operators have to make sure subscribers enjoy the same quality of user experience for voice service while new IP-based data services become available. In this article we review the three solutions, single radio voice call continuity, circuit switched fallback, and voice over Long Term Evolution via generic access, for providing voice service continuity in EPS. The impacts of these solutions on the user experience are analyzed and compared in terms of call interruption, call setup delay, impact on data services, and device battery consumption.