| dc.description.abstract | Cognitive Radio network provides an environment which is able to solve the problem of the inefficient utilization of the spectrum. It helps the unlicensed users to make use of the spectrum together, under the condition of having no influence to licensed users.
In Cognitive Radio network, the transmission quality will change due to the different location or space in the whole network, which is similar to the general network environment. Moreover, the idle spectrum would appear only in the case that the licensed user does not make use of it, which burdens the changeable network environment. Thus, how to make efficient use of the idle spectrum becomes an important issue in the dynamic environment. In many methods presently, it is assumed that there is Fusion center in the network, which is able to integrate the environment information, allocate idle spectrum to unlicensed users efficiently in the centralized decision-making method, and adjust it according to the dynamic environment. However, if there is no Fusion center to allocation the spectrum, then unlicensed users make their own decisions of the usage of channels independently. Under such condition, the spectrum utilization would be inefficient because of the contention.
In this paper, a channel decision-making method considering the dynamic channel condition and the distributed channel decision-making is proposed, which is able to make the unlicensed users coordinate the channel utilization and improve the spectrum efficiency. In the simulation, the result shows that the proposed method can improve the system performance by improving the spectrum utilization, and maintain certain fairness in the aspect of overhead resulting from the handover between unlicensed users. However, under the dynamic adjustment of parameters, the overhead would be decreased due to the fewer numbers of unnecessary handover while keeping the system performance.
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