Research On Spectrum Switching And Spectrum Allocation In Cognitive Radio Networks

With the rapid development of wireless communications technology, spectrum resources are increasingly scarce. Cognitive radio (CR) technology is promising to solve the situation and has become the focus of attention and research in its field.This thesis briefly introduces the background, concepts, capabilities, key technologies and research status of cognitive radio technologies. Then, on this basis, respectively analyzed the spectrum handoff and spectrum allocation. In the third chapter, use information entropy-based TOPSIS algorithm to calculate the weights to eliminate errors caused by human factors so that make objective scientific conclusion. After sample application, the feasibility of the new algorithm has been proved. Through the last simulation, compare the new algorithm and the traditional algorithm, new algorithm has a distinct advantage of total number of switches and system latency.Fuzzy logic system is used in the fourth chapter to complete spectrum allocation. Selecting three factors:spectrum utilization, channel quality, and the distance of network and control center as input, via Fuzzy inference and rules to determine the probability of network access spectrum. Then calculated the net income by the formula. In the simulation, the new algorithm on network revenue to be significantly better than the old algorithm and the complexity of the program is much lower than the old one,which all reflects the superiority of the new algorithm.