| As the fast development of wireless communication technologies, many new kinds of access technologies and diverse requirements of new wireless applications have appeared. This results in more and more requirement and shortage of the spectrum resource. At the same time, the conflict between the network data transmission rate and quality of service, and the reliability and connectivity of wireless network becomes increasingly prominent. The Ad Hoc networks based on the technologies of cognitive radio, improve the spectrum efficiency by using the underutilized bands of authorized users; and the Ad Hoc networks based on cooperative communications, supply space diversity gain and improve rate and quality of transmission by disposing and relaying the data from source node. As the terminal network and constituent part of future mobile communication system, cognitive and cooperative wireless Ad Hoc network is considered as important direction of development of mobile communications and attracts more and more attention.In cognitive and cooperative wireless Ad Hoc networks, one of the most important challenges is how to realize the resource management, such as throughput optimization, spectrum sharing, relay selection, power allocation, and so on. Currently, quite a lot research institutions and researchers have done much work on cognitive radio networks and they have achieved a lot, however, various problems remains to be solved. In this paper, the problem of distributed power allocation in cognitive radio Ad Hoc networks, relay selection and power allocation in multi-hop wireless networks, and relay selection and power allocation in OFDM networks are studied, and the novelty schemes are proposed. We also verify the performance of the proposed schemes by theoretical analysis and simulation methods. The main contributions of this thesis are listed as follows: 1) We propose a distributed power allocation mechanism based on evolutionary game theory in cognitive radio Ad Hoc networks. On the base of analysis of throughput and transmission strategy of secondary users, the best response dynamics theory is leaded into modeling of distributed power allocation among secondary users. Further, we propose distributed algorithm for secondary users, according to the transmission strategies of itself and its neighbors, to carry on the power adjustment adaptively with the power constraints of secondary users and whole network, in order to improve the data transmission rate and energy consumption.2) We propose a relay selection and power allocation mechanism for multi-hop link in cooperative Ad Hoc networks, based on the segment mode and game theory. According to the affection of the process of upstream nodes’relay selection to the other nodes in the same route and the performance of end-to-end multi-hop " link, we define a new cooperation mode:segment cooperation. We analyze the channel capacity and outage probability of this mode, and propose the method of power allocation based on dynamic game theory and principle-agent model in segment cooperation, to allocate power among the nodes joined cooperation and improve their throughput adaptively. We also propose a heuristic algorithm to enhance the channel capacity and decrease the outage probability of the multi-relay multi-hop route; reduce the energy consumption of nodes.3) We propose a joint algorithm in subcarrier pairing, relay selection and power allocation based on energy efficiency of nodes in cooperative Ad Hoc networks, we analyze the energy efficiency of OFDM multi-relay system in amplify and forward mode, design the relay selection criteria based on the energy efficiency and residual energy; propose the asynchronous power iteration method based on energy efficiency, and prove the convergence and the existence of Nash equilibrium in the method. We further propose a joint subcarrier pairing, relay selection and power allocation algorithm, and apply genetic algorithm to optimize the performance of the proposed algorithm. The algorithm can improve the energy efficiency and the survival time of network nodes. |
