Cross-Layer Design And Cooperation Mechanism Research In Cognitive Radio Networks

Compared with cable communication, wireless communication suffers from varying channels, especially the mobile communication. On one hand, fading and shadowing make the wireless channel time-varying, on the other hand, with the development of radio access technologies, the spectrums to bear kinds of radio access technology become scare. Meanwhile, users need various service types in different network with strict QoS requirements. This requires the usage of the spectrum and QoS of service be taken into account comprehensively for the resources scheduling, and optimizing the configuration according to the variant wireless environment, so that the utilization of spectrum and service perception can be improved.In the wireless communication system, many concepts and technology can be explained using the cooperation principle. For example, in cognitive radio network, primary users and secondary users take advantage of the spectrum through spectrum leasing. The aim of cross-layer design is to enhance the system performance by coordination between different layers of the protocol stack, through adjusting the key parameters of PHY layer and MAC layer, and user diversity gain can be also achieved. With the relay technology introduced, there will be more spectrum access opportunities for nodes.So, this dissertation mainly focuses on the cooperating scheme in the cognitive radio network. According to different cooperating unities, the cooperation can be categorized into nodes level and network level. Relay is a key technology in node level cooperation. In the cognitive context, it can significantly increase the opportunities of spectrum access. The resource scheduling scheme in the cognitive relay network is investigated in this dissertation, and a unique scheduling method for complex cooperative network is proposed to realize the multi dimensional scheduling, including the time dimension, space dimension and spectrum dimension.Considering the channel usability, channel quality, power allocation, the dissertation mainly analyses the resource scheduling in complex network. Based on the different QoS requirement of user services, the scheduling solves the problem with nodes cooperation and network co-existence. A progressive resource scheduling is also presented in the dissertation, it can improve the system performance, make a trade-off between the user fairness problem and total cost of the whole system.Finally, focused on the research of radio resource management, load balancing, jointly scheduling are become thorough, this dissertation investigates the key problem in the multi-network coordination -traffic prediction and proposes the implementation algorithm, design the platform used for network planning and optimization,the simulation results prove the algorithm has a better performance.The conclusion is given in the end of this dissertation, and the future research direction is also listed.