Channel Allocation Strategy Study For Cognitive Radio Network

The shortage of the radio resources restricts the continuous progress of thewireless mobile communication. Cognitive radio as a spectrum sharing techniquehas become a focus in the field of wireless telecommunication. Spectrum sensing isan important way to realize the efficient utilization of the spectrum. Through thespectrum environment intelligence sense, cognitive users can get the spectrumholes which are assigned to authorized users but unoccupied. This paper will payattention to the channel allocation algorithm with different optimization goalsusing the idle channel in the spectrum sensing. By the improvement andoptimization of the channel allocation algorithms, channel allocation results meetthe given optimization goals. And we obtain different network topologies based ondifferent optimization objectives.In this paper, we presents a time-frequency mixing network model. In thisnetwork model, we use frequency division multiplexing and time divisionmultiplexing to multiplex channels depending on the relationship between thenodes. Finally, we obtain the tree network results and chain network results whichare satisfied with the goal of maximization bottleneck link rate or maximizationspecified link rate.For the channel allocation algorithm with the goal of maximization bottlenecklink rate, this paper separately researches the tree network and the chain network.In the tree network part, we use the dimensionality reduction algorithm reduce theinitial channel information, and then put the two-dimensional channel informationinto kernel tree routing algorithm. By this method, we can obtain the bottlenecklink topology, and then we use the optimized KM algorithm to assign the channels.At last, we need to assign channels to the nodes outside of the bottleneck link. Inthe chain network part, first, we choose the chain link generation algorithm togenerate the chain link topology, then we use the optimized KM algorithm to assignthe channels to maximize the backbone link rate.For the channel allocation algorithm with the goal of maximization specifiedlink rate, we separately research the tree network and the chain network. In the treenetwork part, we use the improved Floyd algorithm to assign the channels. Thisalgorithm can make as many as remaining nodes access the specified link. At last,we need to assign channels to the nodes outside of the specified link. In the chainnetwork part, we use chain link generation algorithm to generate the chain linktopology. After that, we use the optimized KM algorithm to assign the channels tothe nodes in the specified link and out of the specified link respectively. In this paper, we purpose the improved Floyd algorithm and the optimized KMalgorithm. Through simulation analysis, we can find that the achievement ratio andthe execution time of above two algorithms have obvious advantages. According tothe network and channel allocation strategy, we obtain the tree network and chainnetwork results based on each optimization goal. This paper presents the feasiblechannel allocation strategies based on the engineering practice, and they have goodapplication prospects.