Research On Preprocessing And Variable Step Size Fast Adaptive Beamforming Algorithm

With the continuous development of wireless communication services,attention to adaptive antenna technology is increasing.As a core research direction in the field of adaptive antennas,adaptive beamforming technology has been playing an important role since the third generation of mobile communication systems.Its role has now been widely used in various fields of military and civilian use.Adaptive antennas mainly use various adaptive beamforming algorithms to perform spatial filtering on signals,so that the generated beams have directivity,so as to achieve the purpose of enhancing target signals and suppressing interference signals.In actual application scenarios,the direction of arrival of the desired signal is constantly changing.In order to ensure the adaptive antenna system's ability to track moving targets,The convergence rate should be taken as an important index to measure the performance of adaptive beamforming algorithm.The trade-off between the computational complexity and the algorithm convergence speed of various adaptive beamforming algorithms has always been a difficult problem.Algorithms with low computational complexity generally require a longer convergence speed,while algorithms with fast convergence have higher calculations.the complexity.Therefore,this paper focuses on improving the convergence speed of continuous adaptive beamforming algorithms with low computational complexity.The main work and innovations done include:1.In view of the relatively high initial error of the current continuous adaptive beamforming algorithm,which leads to the problem that the algorithm requires multiple iterations to achieve convergence,a preprocessing method is proposed,which is applied to the LMS and CMA algorithms,so that these two algorithms are at the beginning It has a relatively low error during iteration,which makes it converge with a small number of snapshots.Simulation experiments show that the preprocessing method proposed in this paper can effectively accelerate the speed of beamforming.2.Aiming at the problem that the performance of the traditional fixed-step adaptive beamforming algorithm is limited by the value of the step-length factor,a new variable-stepsize algorithm is proposed,which improves the convergence performance of the algorithm by dynamically adjusting the step-size factor.Compared with the variable step size algorithm in recent years,The algorithm reduces the complexity of calculating step size factor in each iteration,and has good convergence performance.3.In view of the situation that the mean square error of the variable-step adaptive beamforming algorithm at the initial stage of the iteration is still to be optimized,this paper combines the variable-step algorithm with the preprocessing method to comprehensively improve both before and during the execution of the adaptive beamforming algorithm.The speed of beamforming,simulation experiments show that the preprocessing method proposed in this paper can also effectively improve the convergence speed of the variable-step adaptive beamforming algorithm.