Signal Detection And Spectrum Sensing Technology Based On FBMC Structure

The integration of satellite navigation system and satellite communication system can achieve higher spectrum efficiency,fewer satellite load and emergency communication,and the key to achieve the integration system is the fusion of multicarrier structure.FBMC(Filterbank Multicarrier) has many advantages such as higher spectrum utilization ratio,lower outband leakage,which make a broad application of it in intergration system.Good signal dectection and spectrum sensing technique can improve the performance of the integration system.Because of the characteristic difference between multicarrier signals,the signal dectection and spectrum sensing technique must to match the multicarrier structure.Therefore,this paper is propose to research the signal dectection and spectrum sensing technique based on FBMC in integration system.The detail works are as follows:First,the specific scheme of the satellite navigation integrated system is explained,and the importance of the multi-carrier structure FBMC in the integrated system is pointed out.Then,the basic principles of the FBMC transmitter and receiver are introduced in detail,including the role of IFFT / FFT,the analysis of the characteristics of the prototype filter and the aliasing principle of OQAM(Offset Quadrature Amplitude Modulation).Secondly,the intrinsic imaginary interference of FBMC under complex channel conditions is analyzed,and the basic principles of the FFT-FBMC structure and dual-polarization FBMC(DP-FBMC)are introduced in detail.Suitability of both in satellite channel environment is simulated.Then,the signal detection methods under the structure of FFT-FBMC and DP-FBMC are studied deeply.Aiming at the problem that the traditional energy detection method has a large number of samples,a double-threshold sequence detection method is proposed on the basis of proving that the transmission signals of the FFT-FBMC and DP-FBMC follow a Gaussian distribution.Simulations show that this method overcomes the problem of too many samples in the energy detection method,and has a higher detection success rate than the energy detection method under the condition of SNR>-5d B.Then,the spectrum sensing technology based on FBMC structure is discussed.According to the orthogonal characteristics of the FBMC prototype filter,the perceptual deviation of the matched filter perception under the FBMC structure is analyzed in depth,and the impact of the perceptual deviation is reduced by increasing the number of perceptual times.In addition,based on the cyclic spectrum characteristics of the FBMC signal,a cyclic stationary sensing method based on the FBMC structure is proposed.This method can sense a specific subcarrier frequency band under low signal-to-noise ratio conditions.Simulations show that the combination of cyclic stationary sensing and matched filtering sensing can meet the requirements of integrated systems.Finally,an integrated simulation platform for satellite navigation and communication was set up,constructing an integrated satellite navigation and communication system with FBMC structure as the core.The platform can simulate the whole process of satellite navigation and communication integrated system,and intuitively demonstrate the advantages of the algorithm proposed in this paper.