SRVCC Technology And The Optimizing Solution

With the launch of large-scale LTE network, network operators will face many challenges LTE and traditional 2G/3G networks. Supporting calls between LTE and existing networks is one of continuous core problem. SRVCC (Single Radio Voice Call Continuity) is mainly to solve the moves between LTE networks and traditional 2G/3G network, the smooth handover between LTE voice problems and CS domain voice, but the existence of the program end media surface Update NE too elapsed, and lead to the problem of dropped calls voice switching occurs. eSRVCC technology compared SRVCC technology, new media anchor point, reduce the switching process update time end user signaling and bearer channels, it is possible to improve the user in LTE coverage area unevenness handover success rate of the speech. IMS-based VOLTE is a voice technology that can guarantee a high quality of service and user experience, solve data interoperability and roaming, to become the ultimate voice TD-LTE system solutions. SCCAS belong to the IMS architecture system, the treatise include:(1) to study the network architecture, technical features and services about IMS architecture, in-depth study the eSRVCC and SRVCC 3GPP proposed program; (2) on the basis of the IMS architecture to achieve a SCCAS system, including system requirements analysis, design modules, system solutions about key technical points, the system key interface design and key module function; (3) laboratory test data based on China Mobile, the system functionality, performance and other aspects of more latitude for analysis, feasibility and robustness verification system.The main contribution of this treatise in the following areas:(1) To study how the SRVCC scheme is implemented under the IMS architecture, the useage of the existing SCCAS system architecture, as well as the actual deployment of possible compatibility issues. According to the scheme of srvcc, in IMS architecture to construct new sccas business systems network architecture and function model, according to the principle of multi tier architecture design, as the underlying interface system and DB subsystem, business subsystem, registered subsystem and a plurality of logical subsystems and transplantation as basis functions. Design of multiple functional models in the business subsystem, according to different call scenarios, design the corresponding business logic. Then according to the IMS architecture, sccas element is proposed to achieve the requirements of 3GPP srvcc call media anchoring, anchoring signaling, select a domain, domain switching and call routing and other key functions, in sccas system respectively design the DSF, CSAF, DTF logic module realized 3GPP defined business processes, for how users in sccas achieve the user’s registration, call, and user authentication data, basic attributes and service attributes etc. basis functions, is in accordance with on the basis of the existing system of atherosclerosis development, greatly reducing the workload of the basis functions for the development.(2) Research eSRVCC and SRVCC programme of difference, according to the 3 GPP proposed of standard, in IMS network in the added has ATCF/ATGW logic network entity, on added entity according to software engineering of process, for the system needs analysis, system design, detailed design, content; reference SCCAS system of schema, for module of design, business process of design; on SCCAS added ATCF of network, SCCAS also need for corresponding of business process optimization, performance for registered process, and call process, and switch process three most, in registered process in the need on ATCF up of registered Message in the with of XML parameter, for decoding and save; in call process in the, according to registered save of user information for judge whether need for letter makes level of anchor set processing, if not with ATCF of parameter, is implementation SRVCC of anchor set logic, or according to eSRVCC of business logic for not anchor set processing And in the process of switching, SCCAS accordance with ATCF the dialog id to call within the data associated with the Message, subsequent data switching, before release to the calling process.(3) SCCAS system test, for design of system testing, mainly includes the introduction of network testing, test environment, test equipment, According to China Mobile’s functional test data, indicating that eSRVCC system switching delay time is from the original 800ms decreased to about from 230ms,which already meet the 3GPP standard; Call performance in the main purpose is to verify the reliability of the system. Also based on China Mobile’s test data, it is proved that the system has met the requirements of the commercial operation in the eSRVCC performance, the service board load test, the business processing ability and the stability.