同步SRVCC方案的设计与性能仿真

Design and Performance Simulation of Synchronous SRVCC Scheme

将基于IP多媒体子系统(IMS)的单一无线语音呼叫连续性(SRVCC)技术应用于长期演进(LTE)部署的初中期阶段,以实现LTE和2G/3G CS域的语音切换连续性,被业界一致认为是网络共存期间LTE语音业务的经典提供方案。然而,3GPP制定的关于SRVCC相关方案不能满足语音业务实时性的要求,IMS核心网侧媒体更新时间过长。为此,提出一种基于归属域控制的远端媒体优化的同步SRVCC方案。分析SRVCC技术特点和存在问题,通过会话集中和持续性应用服务器的媒体选择功能减少远端媒体的更新时间,并在MSC Server中设定计时器,同步UE的切换时间和远端媒体更新时间,以达到减少中断时延的目的。仿真结果表明,在不增加网络实体的情况下,该方案能满足3GPP中断时延小于300ms的要求。

Single Radio Voice Call Continuity（SRVCC）based on IP Multimedia Subsystem（IMS）is implemented to realize the voice continuity between Long Term Evolution（LTE）and 2G/3G in CS domain during the middle stage of LTE deployments. It is voted by the industry as the target solution to provide LTE voice service during network convergence. But related programs about SRVCC developed by 3 GPP can not meet the requirements of real-time voice service. The main problem is the media update time for too long at IMS core network side. On the basis of the analysis of the characteristics and problems of SRVCC,it proposes the remote media optimization and synchronous scheme of SRVCC under the domain control. The scheme reduces the update time of remote end by Service Centralization and Continuity Application Server（SCC AS）media selection function,and sets the timer in the MSC Server to synchronous UE switching time and remotes media update time in order to achieve the purpose of reducing interrupt delay. Simulation results show that,this scheme can meet the requirements of 3 GPP to interrupt delay in the case without increasing the network entity.