Study On Improved Collaborative Spectrum Sensing Algorithms In Cognitive Radio Networks

In recent years,the rapid development of wireless communication service causes a sharp shortage of spectrum resources and a sharp increase in the demand of users.To alleviate the resource shortage,cognitive radio becomes an effective solution to the current problems.On the one hand,limited and non-renewable spectrum resources limit the spectrum resources can't be as inexhaustible as renewable energy;Second,the past spectrum allocation of resources to take the most ridiculous and unreasonable way,making valuable Resources can not be effectively used;Finally,with the continuous advances in wireless communication technology in recent years,especially the accelerated development of smart phones,the size of the user base has become larger and larger.Aiming at the above problems that have been existed for a long time,this thesis starts from the cognitive radio cognitive theory,and gradually introduces multi-user cooperative spectrum sensing technology,particle swarm optimization and full-duplex relay cooperative sensing technology to improve the probability and throughput of the cognitive users' detection.The main work of this thesis is :(1)The primary user signals are tested using the energy detection strategy.In view of the multi-user collaborative spectrum sensing;two data fusion model is introduced,and the key is deduced in this thesis,the need to optimize the objective function of the soft decision fusion algorithm.In this thesis,the standard particle swarm optimization algorithm to improve the speed of location update equations,the objective function into the food guide of accelerating particle swarm optimization algorithm for performance analysis and simulation verification.(2)The qualitative analysis of the impact of noise uncertainty on the performance of the algorithm is carried out.The results show that the improved algorithm proposed in the third chapter can still obtain higher detection performance under the worst case of noise,which shows that the improvement made in this thesis is effective and reliable.(3)The relay involving collaborative spectrum sensing system with eavesdroppers is studied,cognitive node configuration for spectrum sensing antenna and send more information,to solve the transmission link antenna selection and power allocation problem.The simulation results show that the proposed method can significantly improve the average throughput of the whole system,and the ideas presented in this thesis are successful and effective.