The Reasearch And Implementation Of Spatial Adaptive Anti-jamming Algorithm

In order to meet the increasing demand of users' mobile data traffic,the fifth generation mobile communication technology has been formally commercial and gradually popularized.Compared with 4G communication system,5G communication system uses large-scale antenna array on the base station side to replace the previous multi antenna structure,which can greatly improve the user capacity and spectrum efficiency of the system,and reduce the power consumption ratio of the system.However,with the rapid growth of the users' number,the interference between users in the hotspot area will greatly affect the communication quality,reduce the stability and reliability of the system,and thus affect the user experience and the overall performance of the system.Therefore,the adaptive anti-jamming algorithm based on array antenna is one of the ways to solve the above problems.Adaptive anti-jamming technology has always been a hot research topic in communication systems,and this technology is widely used in radar,sonar,remote control,mobile communications and other fields.According to the characteristics of the hardware structure of antenna array used in the base station side of 5G communication system,this thesis aims to apply the adaptive anti-jamming algorithm to the communication system to improve the anti-interference ability of the system,the mainly studies and work are summarized as follows:1)Firstly,the thesis analyzed the basic theory of the array antenna in detail,and briefly introduced the system structure of the adaptive array antenna,then deduced several common adaptive beamforming criteria,analyzed and compared the application environment and preconditions of these criteria;2)Then,in this thesis,the theoretical research and simulation analysis of the Minimum Variance Distortionless Response(MVDR)algorithm in adaptive beamforming technology and the Multiple Signal Classification(MUSIC)algorithm in spatial spectrum estimation are carried out.Considering the application of this two algorithms,the thesis proposes to use the MUSIC algorithm implements the real-time accurate detection of signal orientation to ensure that the MVDR algorithm can receives distortion-free reception of the expected signal and effectively suppresses the interference signal.In addition,combined with practical engineering applications,considering the high complexity of the matrix inversion and matrix eigenvalue decomposition in the above algorithm,this thesis proposes to use LU decomposition and Cholesky decomposition to implement matrix inversion,and to use the second-order main subdivision real number diagonalization to implement the matrix eigenvalue decomposition which can reduces the complexity of the algorithm and resource consumption during hardware implementation,and accelerates the speed of the algorithms;3)By using FPGA development software System Generator and Vivado HLS,the thesis accomplished the engineering implementation and simulation verification of MVDR algorithm and MUSIC algorithm.And after a comparative analysis of the two development software,this thesis proposed to use Vivado HLS to accomplished the part of the algorithms with high complexity and flexible configuration parameters,and the digital signal processing part of the algorithms can be developed by using System Generator.This method fully combines the advantages of the two development software,will simplifies the FPGA development process of the array signal processing algorithm,and greatly shortens the development cycle of the overall engineering implementation;4)Finally,based on the software radio hardware platform USRP,anti-jamming radio frequency components with integrated FPGA chip and uniform one-dimensional ultra-wideband antenna array,a set of communication adaptive anti-jamming system is built,which fully considers the respective advantages of the MUSIC algorithm and the MVDR algorithm.However,the MUSIC algorithm is used to accurately determine the position of the signal source.After obtaining the accurate position information of the signal,it is delivered to the MVDR algorithm to achieve the distortion-free reception of the target signal position and at the same time effectively suppress the interference signal.Experimental tests show that the suppression capability of the entire communication system to interference signals reaches more than 20 d B,so the entire system has good adaptive anti-interference performance.