Key Technology Research Of The Dynamic Spectrumallocation Based On Cognitive Radio

With the development of radio communication technology, spectrum resource has been more widely used. The scarceness of wireless spectrum hampers the development of wireless communication services. Cognitive Radio (CR) technology is a revolutionary technology of wireless mobile communication, which is considered as a novel method to solve the problem of the shortage of wireless spectrum. Cognitive radio technology, which is considered as a confined concept in coined stage, has become one of ten hotspot communication technologies in the future. Its researches involve network architecture and key technologies from PHY layer to network layer. This thesis mainly researches spectrum allocation algorithm, which is one of cognitive radio key technologies. Spectrum allocation,one important part of the cognitive radio technology,which uses network resources effectively and increases the system capacity, plays a vital role in cognitive radio system performance.At the beginning of this thesis, the three models of the dynamic spectrum allocation algorithm are introduced. Secondly, it mainly studies the existing spectrum allocation algorithms, which based on graph coloring theory. Aiming at the disadvantage of not based on demands of users in existing methods, an improved spectrum allocation algorithm is given, named"A Dynamic Spectrum Allocation Algorithm Combined with Demands of Users". Simulation shows that the proposed algorithm can meet users'demands better and it reduces the time of spectrum allocating. Finally, another improved algorithm is given, named"A Local Optimizing Spectrum Allocation Algorithm Combined with Demands of Users", which is the improvement of the local bargaining algorithm. Simulation shows that the result of the improved algorithm is not as good as global optimizing algorithm, but it reduces the computation time and increases the speed. It adapts the fast change environment better.