Research On Cooperative Detection Algorithm Of Cognitive Radio Based On The Energy Detection

Cognitive radio technology is an important milestone in the history of radio.It can solve conflict about the use of spectrum resources between non-authorized users (cognitive user) who have a steady demand for the spectrum and authorized users (primary user) who have the low utilization of spectrum.It can improve the spectrum efficiency and utilize the scarce spectrum resources more effectively.Among the key cognitive radio technologies, spectrum sensing technology is the core technology of cognitive radio system, only the correct basis of perception, cognitive radio systems can carry out spectrum analysis, management, sharing and decision-making.However, how to sense spectrum efficiently and accurately, that is a hot issue of cognitive radio research.In this paper, we first analyzed the current development status of cognitive radio at home and abroad,and cognitive radio's key technologies, and make spectrum sensing as a research direction.We contrast and analyse three methods of spectral detection theory: matched filter method, the energy detection method and detection of static cycle characteristics.Analysis derived that energy detection method is a simple, a broad application and more mature technology of non-coherent detection.The most important thing is the premise of the unknown signal, energy detection is the optimal algorithm.Secondly,We mainly analyze the detection principle and performance of energy detection method and research its spectrum detection performance under different conditions.We analysis Some cooperative detection algorithms.We make performance simulation about "and" algorithm and "or" algorithm with the changes of cooperative users number and SNR.We validated that the detection probability of "or" algorithm is better than the detection probability of "and" algorithm,but the false alarm probability is not dominant.Finally, We establish a system model in this paper,In practice, each cognitive user's location is different and channel conditions is different, so that the received signal to noise ratio is not the same,According to the weighted method, signal to noise ratio is different, the contribution of decision-making is different.In order to optimize cooperation algorithm,We decide to choose preferred cognitive user who has larger signal to noise ratio.Through the simulation and analysis, We know,in practical cooperation,not all cognitive users to collaborate to get the best detection performance, but a certain number of cognitive users can participate in collaboration with the optimal detection performance,This greatly reduces the complexity of coordination algorithms, while detection performance has been optimized.