LTE network can not provide the traditional circuit-switched voice services, in order to ensure equal revenue while providing a convenient user experience, mobile operators need to operate LTE services while providing LTE voice services at this stage of the IMS-based voice solutions, including the VoLTE (Voice over LTE) and based on circuit switching of CSFB (Circuit Switched Fallback) technologies. While more new patterns in response to competition, mobile operators in order to standardize the GSMA Rich Communication Suite (RCS) solution based on an interoperable IMS specifications, integration services, provide a richer multimedia telephony services.
Voice over LTE (VoLTE) Circuit Switched Fallback (CSFB) Enhanced Single Radio Voice Call Continuity (eSRVCC) Rich Communication Suite (RCS) Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) Home Subscriber Server (HSS)