Research Of Cognitive Radio Spectrum Sensing Technogy Combined With Users’ Difference

Along with the continuous development of wireless communication technology, more and more communication applications are used in people’s daily life. These applications require a large amount of radio spectrum resources, which is limited. The development of cognitive radio is to deal with this challenge. In the cognitive radio network, the user who is not allocated spectral resources is called second user, and the user who is allocated spectral resources is called the first user. The cognitive radio technology hope that the second user could use the first user’s spectral resources, so as to improve the utilization of spectrum resources. Among the technologies of cognitive radio, spectrum sensing is the most basic and most important one. The spectrum sensing technology is directly related to the second user to find and access the idle spectrum resources of the primary user.The current research on spectrum sensing technology focus on the multi-user cooperative sensing technology. In the centralized multi-user cooperative sensing, the second users which participate in the cooperation have different sensing performance because they have different environment qualities. In the traditional fusion method, the second users have the same influence on the final judgment. In that case, the final result may cause some error because of several second users’poor performance. To address this problem, this article propose two method. They use the differences between users from two aspects. The first one is to make the local sensing performance different from the users based on the SNR. The other is to adjust the credibility in the fusion center directly. They reflect the differences between users on the final decision process in direct and indirect way. The main content can be described as follow:To solve the problem mentioned above, the dynamic dual-threshold cooperative sensing method adjust the perception of the second users’results to the final judgment by making the local sensing performances different. The method make the users’ energy threshold different according to the users’SNR. In this way, the second users have different local sensing performances. The method adjust the second users’ weights in the final judgment indirectly. The users who have better sensing performances have a greater impact on the final judgment. The method can improve the detection probability of the system, and reduce the probability of false alarm. In the cluster sensing method, there is a difference between the number of users in each cluster and users’sensing performance. Consequently, the different clusters have different sensing performances. In the traditional fusion methods, the sensing results of each cluster have the same influence on the final judgment. In this way, the accuracy of the final judgment maybe affected because of several clusters’poor performances. To solve this problem, this article propose the cluster sensing method base on the credibility. This method could allocate the different clusters’results with different credibility according to the clusters’sensing performances in the fusion center. The better performance users have a greater impact on the final judgment. The program reduces the impact of the individual clusters with poor performance on the final result. Compared with the traditional method, the proposed method has higher detection probability and lower false alarm probability.We carry out a series of simulation experiments based on the methods proposed above. The experimental results show that the two methods have varying degrees of performance improvement compared with the traditional fusion methods in different experimental environments.