Research On The Technology Of Multi-Terminal Coordinated Network Control In Heterogeneous Networks

Currently, wireless access networks and terminals are experiencing the heterogeneity. User’s terminals are usually equipped with more than two radio access technologies (RAT), including wireless wide area network (WWAN, e.g.2G,3G, and4G) and wireless personal area network (WPAN, e.g. Bluetooth). With the increasing demand on high throughput from mobile users and the serving capacity of single RAT, there is a growing concern on the cooperation between multi-network even the multi-terminal to support increasing requirement. In this context, multi-terminal coordinated communication comes out to fully utilize terminal hetero-access-capacity around the user. Multi-terminal coordinated communication can overcome the disadvantage of traditional single RAT by improving real-time network throughput and service experience. To realize the multi-terminal coordinated communication as building block in future network, there still exist some challenges that need to be resolved.Under this circumstance, the scenario of multi-terminal coordinated communication is analyzed in this thesis, as well as the system requirements. Based on the IMS session control architecture in telecom operator networks, the session oriented coordination control mechanisms including terminal registration, terminal discovery, triggering of session request, context management are designed. The handover mechanism for coordinated terminals is designed to assure the continuity of service regarding the high disturbing of terminals. Moreover, the address binding mechanism between terminal and user identity is also researched. The cache design is introduced even to the terminal side to offload in-network flow so that the network effective capacity is improved.Concurrent Multi-path Transmission (CMT) for multi-terminal and multi-interface plays key role in multi-terminal coordinated communication system. Regarding the quality of the diverse wireless links, CMT splits service date to different wireless access network to achieve QoS goal. Current models of network cooperation assume the service rate of WPAN is constant which might be impractical. Based on the queuing models for the target coordination scenario, the impact of WLAN capacity limitation on the traffic allocation is researched by acquiring the close form expression of the service rate of WLAN system. An optimal terminal selection algorithm is proposed which can select several partners out of candidate terminals to minimize the whole delay of the system. Simulation results show the feasibility and performance of the algorithm.