Research Of Wideband Spectrum Sensing Based On Orthogonal Dual Polarization Antenna

With the development of information and communication technology, the huge demand of wireless service makes the shortage of spectrum resources. And the traditional static spectrum allocation policy also leads to the low spectral efficiency. Cognitive radio technology adjusts the occupied spectrum resources dynamically through the real-time perception of the surrounding spectrum environment, so as to realize the effective use of spectrum resources and alleviate the shortage of spectrum resources. In order to seek more available spectrum resources,cognitive radio spectrum sensing is also extended from narrowband to wideband. For the research of wideband spectrum sensing, when using the traditional Nyquist sampling method, the high sampling rate and large sampling data will bring great challenge to the sampling devices. The Bayesian compressive sensing method can achieve low sampling rate directly applied to wideband spectrum sensing. In this paper, dual polarization antenna receiving system is used to realize wideband spectrum sensing, and how to process the compressed signal to reduce the computation and estimate the arrival angle to improve the wideband spectrum sensing performance is studied. This paper relies on the National Natural Science Foundation Project "polarization wideband spectrum sensing and control mechanism" (project number: 61372116),the specific research contents are as follows:(1) Summarizes the basic principles of cognitive radio and introduces its development status and challenges. The existing spectrum sensing algorithms and compressive sensing algorithms are analyzed, and the necessity and feasibility of wideband spectrum sensing are pointed out. And the polarization correlation theory is introduced. It is pointed out that the wideband spectrum sensing algorithm based on dual polarization antenna does not consider the signal combining problem and the incoming wave direction of angle.(2) For the problem that the single polarization antenna affects the sensing system stability in wideband spectrum sensing, a Bayesian compressive spectrum sensing algorithm based on orthogonal dual polarization antenna is proposed. In this algorithm, the Bayesian compressed sensing method is applied to wideband spectrum sensing.The orthogonal dual polarization reception system is used to directly combine the compressed sampling signal and then restore it. Theoretical analysis and simulation experiments show that Bayesian compressive spectrum sensing algorithm based on orthogonal dual polarized antenna compared to the traditional algorithm can effectively reduce the computational complexity and has a better detection performance.(3) In order to solve the problem that the received signal affects the performance of wideband spectrum sensing system, a Bayesian compressed spectrum sensing algorithm based on direction of angle estimation is proposed. Firstly, the Bayesian compressive spectrum sensing model considering the direction of angle is established, and then the estimation of direction of angle is studied. The algorithm achieves the purpose of improving the sensing performance by completing the estimation of the direction of angle and then bringing the results into the spectrum sensing model. Finally, the simulation results show that the proposed algorithm can effectively enhance the wideband spectrum sensing performance compared with the Bayesian compressive spectrum sensing algorithm without considering the incoming waves direction of angle.This study shows that the wideband spectrum sensing algorithm based on orthogonal dual polarization antenna can improve the stability of the sensing system, reduce the computational complexity and improve the performance of spectrum sensing.