Research And Design Of Spectrum Sensing Algorithm Based On Cyclostationary

With the rapid update of wireless communication system and the rapid growth of its user group,the demand for wireless spectrum has also increased dramatically,and wireless spectrum resources have become the most important resource in the information society.Cognitive radio technology has the ability to perceive idle spectrum,which can enable unauthorized users to access licensed frequency bands and improve spectrum utilization.Therefore,it has become one of the more popular research directions in the field of wireless communication.Real-time perception of licensed spectrum usage is the foundation of cognitive radio technology.The current commonly used spectrum sensing methods include energy detection,filter detection and cyclostationary feature detection.The matched filter detection method needs to know the priori information of the primary user signal completely,and the cognitive system needs to equip each type of authorized user with a dedicated receiver,which is costly and not applicable.Energy detection does not require known priori information,but the determination of its threshold is greatly affected by noise,and its performance is poor in the case of harsh channel conditions.Through comparative analysis,this paper chooses to use the cyclostationary feature as the detection feature of the primary user's spectrum perception.This is because this feature can explore the cyclic stationary property of non-stationary random signals,and:has strong anti-interference ability.In addition,the corresponding detection algorithm is a blind detection algorithm,and does not need to know the a priori information of the signal to be detected,making the algorithm suitable for most application scenarios.At present,almost all modulated signals used in wireless communication systems have cyclic stationary characteristics,so this detection method can be applied to the detection of almost all signals,and has wide applicability in spectrum sensing.In this paper,on the basis of in-depth research on the theory of cyclostationary feature extraction and detection,in order to solve the accuracy problem of spectrum detection of the primary user in the multipath fading channel on the sea,a cognitive radio spectrum sensing algorithm based on multi-antenna cyclostationary feature detection is proposed.This algorithm makes full use of the characteristics of multi-antennas with better anti-channel fading performance.Aiming at the current multi-antenna merging algorithm that does not take into account the effects of related fading,a maximum ratio combining algorithm based on the optimal weight correlation value is proposed to make it is more suitable for the environment of marine wireless transmission channels.After combining multiple antenna signals,a cyclostationary detection algorithm performs the perception of the licensed spectrum.Through simulation comparison and verification,the scheme proposed in this paper can achieve more accurate perception of the primary users with weaker energy in multi-path fading channels.On the basis of theoretical research,this subject has also been verified by practice.The FPGA platform has been used to complete the engineering design of the theory algorithm described above,and the timing of the function has been verified by the simulation waveform diagram.Thus completing the transformation from theoretical research to engineering practice.