Research On Spectrum Sharing Technology Considering Fairness In Cognitive Radio

With the development of wireless communication technologies,the spectrum resource has become more and more crowded.However,the average using ration of licensed spectrum allocated by traditional way is low.In order to solve the proble,cognitive radio technology is developed to utilize the unused authorized spectrum and increase the efficiency of spectrum by dynamic spectrum access. Spectrum sharing technology is a very important research direction in cognitive radio,a lot of spectrum sharing methods simply improve the network throughput without considering the fairness of spectrum allocation,The results show that simply maximizing thoughput may result in a severe bias on spectrum allocation,It results that the transport needs of many cognitive users are not met,it is very important to research the fair spectrum sharing technology.In this paper, we study joint spectrum allocation and scheduling problems in cognitive radio wireless networks with the objectives of achieving fair spectrum sharing.this paper proposes two kinds of spectrum allocation algorithm,one is the spectrum allocation algorithm for the protocol model,and another one is the spectrum allocation algorithm for the physical model,these two algorithms take into account the fairness of spectrum allocation.The scheduling algorithms are used to schedule the transmission modes obtained by the spectrum allocation algorithms.Based on the two proposed algorithms respectively,three scheduling algorithms are compared in this paper through simulation:the MAximum throughput Spectrum allocation and Scheduling algorithm (MASS),the Max-min fair MAximum throughput Spectrum allocation and Scheduling(MMASS),the Proportional fAir Spectrum allocation and Scheduling(PASS).The results show that,in all simulation scenarios,the MASS algorithm performs best in terms of throughput but suffer from a severe unfariness on rate allocation among users,the traffic demands of some users are not satisfied at all.However,all the other users obtain very high demand satisfaction factor values.Compared to the MASS algorithm,the MMASS algorithm and PASS algorithm perform less throughput,the average throughput is about 96%of the maximum achievable throughput.A good tradeoff between throughput and fairness can be achieved by PASS algorithm.