Research Of Collaborative Spectrum Sensing Technology Based On Cognitive Radio

Nowadays, the contradiction between increasing demand for spectrum and scarce spectrum resources is a major bottleneck in the development of wireless communications. However, according to the survey, the utilization of spectrum resources in the licensed spectrum band is very low. Cognitive Radio technology has been proposed to solve this puzzle. Cognitive Radio is able to search free spectrum resource among licensed spectrum band, can utilize spectrum resource dynamically under the premise of having no interference to licensed users, and could became a fundamental solution to the problem of unreasonable spectrum scheme caused by the fixed allocation policy of spectrum resources. Spectrum sensing technology is the key integrant in Cognitive Radio, is the basis and precondition for implementation of Cognitive Radio. This paper carries comprehensive study on how to improve the detection performance of spectrum sensing technology.This paper recounted the history, current study and related concepts about Cognitive Radio and spectrum sensing technology, analysis and studies the spectrum sensing technique based on the local spectrum detecting scheme, chose energy detection algorithm as a research focus as a result of Cognitive Radio technology must having ability to detect various primary user signal on the basis of comparing the different detection algorithm, mainly analyzes the principle of energy detection algorithm, studies the performance in AWGN channel and Rayleigh fading channel, and simulate the performance of energy detection algorithm under the different channel respectively.Due to multi-path fading and shadowing, detection performance has a serious decline under the fading channel in local spectrum detecting scheme. Consequently, the paper carries further study on collaborative spectrum sensing to overcome the disadvantages in single node detection. According to the analysis of structure in collaborative spectrum sensing system, the paper studies centralized and distributed collaborative pattern and compare the performance of them. On this basis, the paper studies data fusion rule based on centralized collaborative spectrum detection, and researched the Chair-Varshney algorithm. According to relationship of decision algorithm, the paper deduced the expression of global false alarm probability and detection probability in Chair-Varshney rule, and analyzed the performance of spectrum detection combined simulation experiments.The paper apply the clustering method into collaborative spectrum sensing, researched a spectrum detection program based on cluster collaboration, designed system structure and detection procedures and carries further studies on data fusion rule in clustering collaborative detection. Simulation results show that, the scheme based on clustering collaborative detection is able to improve the performance of spectrum sensing.