Research On Voice Call Continuity Technologies Of Volte

LTE is an important fourth-generation mobile communication technology, whose unique advantage is:high bandwidth, and large capacity etc. When LTE-scale deploys with2/3G coverage as a supplement, LTE will co-exist with the traditional circuit and IMS in some periods, and provides users with voice services silmutaneouly. Voice service is the necessary infrastructure of mobile telecommunications services, and hence some mechanism needs to be escalated to ensure the continuity of multi-mode terminal for voice calls.This paper analyzes the pros and cons of VoLTE technology based on the VoLTE specification of VoLTE voice solutions. Then it conducts further research on VoLTE as to solve the current problem of its session continuity, summarizes all the scenarios in which the interruption of session continuity may happen, and finally concludes the emphasis of Voice Performance Optimization is the corresponding technology of session continuity, which are DSF and SRVCC optimization.Afterwards, the paper analyzes the current solution of DSF and SRVCC solution’s network architecture and signaling interaction process, and conducts empirical analysis on the factors that may affects their performance through laboratory testing and formula derivation. Then this thesis proposes two new solutions for DSF, analyzes their alternative route in various scenarios, and conducts quantitative analysis on the capacity demand of each network elements.This provides references for MSC’s SSP processing ability and the ability to clear traffic of GMSC. On the basis of it, the paper further proposes some enhancements on the solution and creates a new optimized solution and analyzes its possible improvements on the performance. Also this thesis executes the practical outdoor experiment to verify the performance of switching function of eSRVCC improvement solution, and evaluates the enhancement effects of the solution on the interruption of LTE voice session continuity. Finally, the paper summarizes the requirements to various aspects of network of the optimization solution "DSF" and eSRVCC, concludes the possible problems in terms of practical deployment, proposes some new improvement solutions, including:introducing eMSC to implement "bridge" between circuit domain "switching target MSC" and IMS SBC anchor; proposing to establish many eMSC in various provinces as a network organization solution of Sv interface; implementing the audio proprietary deactivation process in eSRVCC with PCC archetechture to avoid user session interruption. All of these provide references for mobile operators to deploy VolTE and EPC networks.