Seamless voice over LTE

Long Term Evolution (LTE) as an evolution of fourth generation (4G) technology offers high data rate of upto 100 Mbps for data applications. But it lacks native support for Circuit Switched (CS) voice service which has been the main revenue generator for operators. This introduces the problem of how to provide voice call when a user is in LTE and how to ensure voice call continuity when it moves out of LTE coverage. There are possible technical solutions e.g CS fallback, Single Radio Voice Call Continuity (SRVCC), Voice over LTE via Generic Access (VoLGA), third party services like skype for providing voice call and voice call continuity over LTE. The paper compares various aspects of these solutions and suggests possible roadmap that operators can adopt to provide seamless voice over LTE.