Research On The Spectrum Utilization Rate Of Cognitive Radio And Cooperative Relay Technology

The rapid development of the wireless mobile communication industry has made non-renewable spectrum resources in short supply.Cognitive radio technology emerges as the times require.The technology realizes the sharing of spectrum resources between secondary users and primary users.At present,the research of cognitive radio technology mainly starts from four directions:spectrum sensing,spectrum allocation,spectrum sharing and spectrum switching.The focus of this paper is to optimize spectrum allocation algorithms and schemes to improve spectrum utilization.Secondly,for cognitive users who need to reduce their own transmit power to reduce the interference to the primary network,leading to the problem of small throughput of cognitive radio network,the cooperative relay technology is introduced into cognitive radio system.This papermainly studies the cooperation among cognitive users to improve end-to-end throughput and communication quality of cognitive users.Firstly,it describes the significance and background,overseas and domestic research status,as well as the organizational structure and work arrangement of the paper.And it introduces the relevant theoretical knowledge of cognitive radio system and cooperative relay technology,and discusses three application scenarios of cooperative relay technology in cognitive radio.Secondly,based on the original Glowworm Swarm Optimization(GSO),an improved Frog-leaping Glowworm Swarm Optimization(FGSO)algorithm is proposed.The improved algorithm is used to optimize the spectrum allocation scheme and improve the spectrum utilization.The new algorithm introduces the idea of group division,so that the global optimal information is transmitted in the whole population.The fixed step size is changed to the adaptive variable step size.The step size is dynamically adjusted by the adaptive coordination factor to accelerate the convergence speed and the search precision.It was measured by four standard testing function and CRN model.The results show that FGSO has more advantages.Finally,the cooperative relay strategy between cognitive users is studied to improve the end-to-end throughput of cognitive users.Under the system model,the mode of channel allocation and the optimal design of power allocation are studied.An optimal single-relay selection scheme combining channel allocation is proposed,and the optimal mode of channel allocation is performed for the best single relay.The system can further improve the end-to-end throughput by means of direct transmission,double-hop transmission,and cooperative transmission.Compared with the multi-relay scheme,this scheme can significantly increase the throughput with low system overhead and complexity,and it has more practical application value.