Cross-layer Optimization For Wireless Resource Allocation In End-to-End Reconfiguration System

Nowadays, wireless communication has faced two major problems: the first one is scarce spectrum resource is not utilized efficiently enough; the second one is the convergence of heterogeneous networks would be a great tendency for the future. In order to flexibly utilize kinds of different access technology and wireless resource, especially spectrum resource, and obtain the maximized system performance gains, a unified end-to-end communication networks platform to hold all these heterogeneous systems is needed. In this situation, end-to-end reconfiguration system has been researched, which aims at optimization of system total performance, and dynamically allocate and use spectrum resource and support automatic reconfiguration of all the network nodes, according to the dynamic wireless communication environment and users'needs, to use the resources with high efficiency and provide seamless and high-quality service experience.In the process of using resource flexibly and accessing kinds of different system, the factors which need to be considered, and resource objects which need to be managed could be complex, always cross-layer and even cross-system. Therefore, cross-layer optimization method is introduced in this thesis to investigate the relationship between the factors and the objects and adjust the network nodes jointly to obtain the system total performance gains.Until now, there have been lots of research achievements about wireless resource management optimization in end-to-end reconfiguration system. They contain wireless resource allocation, admission control, load balance, joint session scheduling and mobility management. Here, in this thesis, cross-layer optimization based wireless resource allocation in end-to-end reconfiguration system is focused, and two typical scenarios are investigated.Firstly, a cross-layer optimization scheme for QoS guarantee in multi-user and multi-service OFDMA system is proposed. In this scheme, the compound objectives of QoS (requirements for data rate, delay, packet loss, etc.) are comprehensively considered. Further more, a model has been established to map these objectives into the lower layer parameters. Multi-user diversity is utilized by jointly adjusting the certain physical and link layer parameters along with allocating the OFDMA resources to improve the system throughput and the spectrum efficiency on the basis of QoS guarantee.Secondly, a information exchange and resource management mechanism supporting cross-layer optimization in relay-assisted cognitive radio system is designed. Compared to the existing schemes, this scheme can support the system to select more comprehensive information and make more optimized decisions about resource allocation, provide more satisfying service and improve the resource utilization.Furthermore, this thesis focuses on how to allocate resource appropriately to fulfill users'call-drop and datarate demands, and meanwhile increase the meaningful system throughput in the CR relay system. At first, a system model with Joint Relay selection, Spectrum allocation and Rate control (JRSR) is built and the problem is formulated. Then, a three-stage heuristic algorithm is proposed to address the JRSR problem and a suboptimal solution is found.In the end of this thesis, a summarization is presented and the potential work in this research area is pointed out.