Research On High Efficiency Broadband Spectrum Sensing Strategy And Transmission Scheme In Cognitive Radio Networks

With the rapid development of wireless communication network, wireless spectrum resources are assigned to different communication systems according to different spectrum bands.This fixed frequency assignment leads to the deficiency of the resources of some frequency bands while other bands are not efficiently utilized. As a kind of intelligent spectrum sharing technology, cognitive radio can detect the idle spectrum resources dynamically and reutilize them, improving the dynamic management of the radio spectrum resource and increasing the spectrum efficiency.However, as the Green Communication is rigorously advocated, the cognitive radio technology of the public-oriented mobile communication system should not only promote the spectrum efficiency, but also be designed with optimized energy saving methods in the cognition process in order to guarantee better user experience and to facilitate energy conservation and emission reduction at the same time. Aiming at these problems, this paper focuses on broadband cooperative and spectrum sensing technology in the public mobile communication networks, and explores how to improve the spectrum utilization rate during spectrum sensing and how to reduce the energy consumption of the system during perceptual information transmission.The research work of this paper mainly includes the following aspects:1. The research status of the current spectrum sensing is presented, the algorithm of spectrum sensing based on the transmitting terminal of the authorized users is studied in detail, and especially the implementation method of the spectrum sensing in cognitive radio is analyzed.2. Aiming at the problem of low utilization rate of traditional spectrum sensing, the adaptive spectrum sensing strategy is proposed. This method adaptively selects the current CR user's behavior choice to determine whether the behavior of the next CR users is sensing the channel, transmitting data or channel switching according to the best decision algorithm, which reduces the cost of sensing, and improves the utilization of spectrum.3. On account of the high energy consumption during the transmission of the perceptual information in cooperative spectrum sensing, the strategy of transmitting perceptual information base on the fountain code is proposed, which optimizes the degree distribution of fountain code and compares it with the performance of conventional degree-distributed fountain code. Based on the channel coding of the modified fountain code, the energy consumption of the transmission of perceptual information is decreased.4. For the data redundancy and the high energy consumption of the sensor nodes in cooperative spectrum sensing, the clustering structure to organize the sensor nodes is proposed. Based on the framework of centralized the cooperative spectrum sensing, and according to the transmission of multi-user clustering, this method transfers the perceptual information of secondary users to cluster head to judge, and then the judgment will be transferred to the perceptual information fusion judgment center, where a verdict of whether the main user exists will be made. As a result, the detection probability of the system is raised and the energy consumption of transmission is reduced.