Solution to Reduce Voice Interruption Time during Handover of VoLTE Call in Enhanced Single Radio Voice Call Continuity

LTE network is a packet switched based network, which does not support circuit switched network feature like voice call. Operators have been trying to deploy LTE network in phases and in parallel they are supporting legacy networks too. It is necessary to support voice call. There are many approaches for supporting voice call to serve customer. Circuit Switched Fall Back (CSFB), Simultaneous Voice & LTE (SV-LTE), Over The Top solution (OTT), Voice over LTE via Generic Access (VoLGA) and IMS based Voice over LTE (VoLTE). SRVCC is a voice call handover process for an LTE user, while it is in active IMS based voice session. In case of SRVCC, control is performed by the home network which causes voice interruption & call drops. To overcome these issues ATCF and ATGW entities have been introduced. This paper explains about the issues, causes and solution in SRVCC.