Key Techniques Of Always Best Connected Services In Next Generation Mobile System

With the development of wireless communication technology, various radio access technology is put forward and deployed over the last decade. Meanwhile, the existing radio access networks is evolving. For example, 3G mobile systems are evolving into HSDPA and LTE. 4G mobile system is proposed to integrate all of these radio access technology into a common network called the open wireless architecture platform. As one of main features of 4G mobile system, Always Best Connected (ABC ) services enable users to choose the best available access networks in a way that best suits their needs. How to provide users ABC services meanwhile keeping efficient power consumption and efficient spectrum utilization is a challenge for 4G mobile systems and future personal communication systems. The aim of this dissertation is providing a practical framework for ABC networks. Moreover, it gives the detailed information about how to design the main components of ABC networks.The definition and reference model of ABC are introduced in the second chapter. Moreover, the seven components of ABC networks: Access Resource Discovery, Network selection, Mobility Management, A4C support, Profile handling and content adaption are introduced briefly.As the first step to realize ABC networks, Access Discovery is introduced in third chapter. Ongoing researches of Access Discovery are classified into two classes. One class is Location-based Access Discovery (LBAD). It is discovered that LBAD can be model as Orgin-Derivate Pattern Classification (ODPC) problem. After the general framework of ODPC is proposed, A multiple PNN based Access Discovery framework is introduced. The simulation of the frameworks demonstrates to be more accurate and reliable than general multiple pattern classification systems.The definition of Adaptive Access Resource Discovery (AARD) is introduced in fourth chapter. A Negotiation-based AARD system is proposed. The scheme realizes AARD while it does not bring change towards infrastructure and terminals. However, it has disadvantages such in power consumption and spectrum occupation.In order to improve power consumption and spectrum utilization, a Location-based AARD system (LBAARD)is proposed in fifth chapter. The proposed system is based on reconfigurable radio, Service Location Protocol and Location Based Services. The performance analysis and simulation show that the proposed scheme improves greatly in the power consumption of terminals as well as the spectrum efficiency of the whole system.As ongoing network selection cannot satisfy user's needs, a context-aware network selection scheme is put forward in sixth chapter. The scheme classifies related context to local context and remote context. Dynamic network selection model is generated by an Expert System based on local context. Remote context is collected and processed according to network selection model in order to select the "best" network under current context. A case of the context-aware network selection is introduced in detail to verify the feasibility of the proposed system.At last, considering the status of future mobile system, a practical ABC network solution is proposed based on mobile IPv6. It not only provide ABC services to users, but also saves power consumption and spectrum occupation. The performance analysis and simulation show that the solution improves when the probability of using LBAARD increases.