The Study, Based On Cognitive Radio Channel Allocation Strategy

With the rapid development of wireless communication technology, the usage of unlicensed spectrum has become more and more crowded. So far, most spectrums employ fixed allocation mechanism, and licensed spectrums are rich but a large number of them are scarcely used. The contradiction obviously restricts the development of those wireless communication businesses. Cognitive Radio (CR) technology effectively alleviates this contradiction. With the support of intelligence, it senses the spectrum environment, automatically search and use idle spectrums, then on the basis of a certain algorithm, it adjusts its own working parameter, and finally realize the multiplexing of spectrums.In the thesis, we first introduce the background, research and application status of CR technology, and describe some channel allocation models. Then direct to the characteristic of distributed Cognitive radio network, we research on difficult points and key issues of CR MAC protocol design in depth. Based on a kind of low-cost node physical platform with three non-independent transceivers, we propose a new kind of CR MAC protocol--DCC-CR (Dynamic Control Channel based Cognitive Radio) MAC protocol. It avoid the bottleneck problem when using fixed control channel, and on that basis, we add power control mechanism to it, which improves channel-multiplexing of network At last, we design a CR-node simulation model on the platform of NS2, and the simulation results show that our protocol can effectively improve the throughput of CR network.After a deep study on CR network, we reach some achievement as follows: (1) Direct to the defect of nowadays MAC protocol of CR network, we propose a Dynamic Control Channel based CR MAC protocol. (2)Propose a new node synchronization mechanism, which decrease the nodes'dependence on specific system time, and improve the efficiency and flexibility of the CR network. (3)Direct to model of CR network and DCC-CR MAC protocol, we propose a new power control mechanism which increases spectrum-multiplexing. (4)Based on NS2, we successfully construct a simulation model which support multi-channel, multi-interface, power controlling and CR network, which verify the effectiveness of DCC-CR MAC protocol. Our research results provide a channel resource allocation resolution with utility value for distributed CR network, and a link level simulation platform with a certain generality for the research of multi-channel wireless network.