SRVCC Enhancement Solution Research And Improvement

LTE, with the advantages of high spectrum efficiency, high bandwidth, and large capacity etc, is an important wireless technology of the next-generation mobile communication systems. With large-scale expansion of LTE network in the future, network operators will be confronted with the long-term coexistence of LTE and multiple networks like GERAN/UTRAN and so on. Pertinent interoperability technologies and strategies can realize the complementary and win-win situation of these multiple networks, and significantly improve the operator's investment efficiency, and through reasonable allocation of multiple services between different networks, user experience can be enhanced and service quality can be improved.Voice service is the core of mobile communication. While deploying the LTE system, mobile operators need to support the continuity of voice service between LTE and currently existent GERAN/UTRAN system. The problem of voice service continuity, which specifically means how to maintain the continuity of the voice service when UE moves between network with support of VoIP service and network without support of VoIP service, must be addressed when the telecommunication network evolves into all-IP network. Currently, for the interoperability of LTE voice service, solution based on IMS network and SRVCC is voted by the industry as the target solution to provide LTE voice service.3GPP has established a special work group and has released R8/9 SRVCC solution (TS 23.216) one after the other. But this solution cannot meet the real-time demand of voice service, mainly due to the long and unstable delay at the IMS core network side caused by the media plan update of the remote terminal. Therefore the standardization organization has set up a work item to enhance SRVCC, and for the disadvantages of SRVCC, three main enhancement ideas and solutions are proposed to research the optimization and enhancement of SRVCC handover performance. Based on the current optimization and enhancement ideas and solutions and through the analysis of each enhancement solution process, the paper makes clear the key factors for the enhancement of SRVCC handover performance and the present deficiencies of each solution, and proposes a novel SRVCC enhancement idea and solution; and in addition, the paper also gives a solution for the call drop problem after the UE handover in the SRVCC scenario.