Cooperative Sensing Scheduling And Network Selections Of The Cognitive Radio Network With Multiple Licensed Networks

Cognitive radio technology is an effective way to solve the contradiction between the rapid development of wireless applications and inefficient spectrum allocation.However,the preemptive priority of the primary users(PUs)and the space time variation characteristics of the idle channel lead to the unstable performance of the cognitive radio network(CRN).With the development of network convergence technology and the popularity of het erogeneous networks,the cognitive radio network with multiple licensed networks(CRNMLNS)is becoming possible.CRNMLNS provides more spectrum resources and network selections.In view of the low sensing accuracy of existing sensing technology in CRNMLNS,the cooperative sensing scheduling of secondary users(SUs)was studied.In the case of false sensing,the network selection problem was studied based on the perceived accuracy of cooperative sensing scheduling.A continuous time Markov chain model was us ed to analyze the spectrum characteristics of CRNMLNS.Based on the analysis of user’s behavior to the spectrum,the infinitesimal generator matrix was established,and the steady state probability and the conditional steady state probability of known SUs distribution were calculated.In order to increase the accuracy of spectrum sensing for CRNMLNS,a cooperative sensing scheduling scheme based on discrete particle swarm optimization(DPSO)algorithm was proposed.The different sensing ability of SUs,the statistical characteristics of spectrum,the anti-interference ability of PUs and other factors were considered.Two integer programming problems on cooperative sensing scheduling scheme were established from two aspects: PUs and SUs respectively.The DPSO algorithm was used to solve two functions.The simulation results show that the spectrum sensing accuracy of the cooperative sensing scheduling scheme based on DPSO algorithm is superior to the random scheduling scheme and the greedy scheduling scheme bas ed on SNR.Based on the above obtained spectrum sensing accuracy,the network selection problem was studied,and a sub optimal network selection scheme was proposed.An analysis of SU’s access behavior was carried out in the case of imperfect sensing.The steady state probability of the network,the blocking probability and dropping rate of the SUs were calculated.To maximize the throughput of CRN,a mathematical model of the network selection problem was established.The optimal network selection algorith m was used to solve the objective function by reducing the dimension of the optimization method.The simulation results show that compared with the random network selection scheme and greedy network selection scheme based on the number of idle channels,the sub optimal network selection scheme obtains a higher throughput.