Research On Beamspace Robust Adaptive Beamforming Technology

Currently, in the communications industry, the rapid development of wireless communication technology of signal processing have gained the attention of an increasing number of the researchers, especially, array signal have been widely applied to use in wireless communications on a variety of electronic devices, such as radars, sonar, microphone array signal processing, medical imaging, wireless communication, the field of mineral exploration and so on. The purpose of using the array signal processing beam-former is distinguishing the useful signals from the interferences and noises. The vector control weight of The adaptive algorithm can change as much as possible in time according to the sample data, in order to keep interference noise ratio of the signal to maximize retention the output of the beam-former, this is the first study of the origin robust algorithm is robust in the beam-former the mismatch and interference colors of the output conditions can still maintain the output beam without distortion. We know the weight vector is consisted of two parts according to the expression, the one part is a sampled signal autocorrelation matrix which whether contains a desired signal into the case or not; the other part is the signal control vector, which also whether can get precisely. Autocorrelation matrix is generally sampled signal due to the restrictions of equipment and technology, we are taking the sample survey approach, while pointing vector cannot be precisely determined in practical applications, so there is a certain point error vector for the situation, This paper provide a simplified calculation when there is an error vector pointing, resulted in keeping the output steady beam-former beam algorithm, we call this algorithm is a robust Beam-space simplified eigenspace-based adaptive algorithm.when the presence of interfering signals exist in the situation, in the paper, we present a Beam-space deep null level adaptation algorithm.1Firstly, the article explains the basic knowledge and the three common use criterions of adaptive beam-former array signal processing design. Secondly, when the pointing error of the beam-space beam desired signal falls on the edge of the main lobe of the beam, the robustness of the beam is declining sharply. The paper proposes a rotation angle of orientation of each error, and then getting the average of pointing to the right of the average of the two orientated control vector. Meanwhile, in order to reduce the amount of calculation, we use reduced-rank transformation, which is we transform the array signal from the array-space to beam-space, we know that the beam the beam eigen-spacae can be divided into signal subspace (including interference signal) and the noise subspace signal, in order to reduce the calculation amount of feature space decomposing brings, the paper use spatial covariance matrix inverse of high order power to approach the signal subspace.It will not only be able to form a stable beam, but also can reduce the amount of the computation, the modified beam-space eigenspace-based algorithm, having a certain practical value of the project.2considering the propagation of signals in complex electromagnetic interference space, the interference signal cannot be avoided, therefore the useful signal receive faintly, how to distinguish the interference signal from interference in the beam is becoming a focus of study of scientific research aspact. On the beam-space field, according to the beam direction zero figure in the formation of interference exists a positive correlation between trap depth and intensity of the interference signal, this paper propose to strengthen the interference factor to automatically increase the power of the weak interference signal, enabling the beam direction can be formed deep nulls. The experiments’results about the power spectrum of the interfere signal power spectrum, forming beam, the output SINR interference signal changes with the number of samples, showed that how much is whether interference coefficient, the beam-space adaptive algorithm can accurate pointing directions of interference signals, the bigger the interference coefficient is, the deeper direction of interference null depth is.