Research On Array Beampattern Control Theory And Algorithm

Array signal processing is an important branch of signal processing and has a wide range of applications in many fields such as,radar,wireless communications,and so on.This dissertation studies array response control theory and algorithm using mathematical theory.The mathematical theory discussed mainly include:linear space theory,orthog-onal projection theory,oblique projection theory,optimization theory,geometric method and so on.The algorithms and related applications include:flexible array response con-trol,robust sidelobe control and synthesis,phase-only array response adjustment,low-cost secure transmission using phased-array architecture,robust array parameter estima-tion.The main contributions and innovations of this dissertation are summarized as fol-lows:(1)A novel accurate array response control(A~2RC)algorithm is proposed.The A~2RC algorithm deals with the problem of how to accurately control the array response at a given direction.By applying the A~2RC algorithm,a new pattern synthesis approach for arbitrary arrays is developed.A multipoint accurate array response control(MA~2RC)algorithm is proposed and its application to beampattern synthesis is investigated.More-over,in order to avoid possible beam axis shift in pattern synthesis,a modified MA~2RC(M~2A~2RC)algorithm is proposed by imposing a derivative constraint on the direction of beam axis.The problem of how to optimally and precisely control array response levels is addressed and the optimal and precise array response control(OPARC)algorithm is pro-posed.The applications of the OPARC algorithm to array signal processing are studied.It is applied to realize array pattern synthesis,multi-constraint adaptive beamforming,and quiescent pattern control.(2)A new scheme based on weight vector orthogonal decomposition(WORD)is proposed to control the array response at a given direction and a novel WORD-based approach to pattern synthesis for arbitrary arrays is devised.A closed-form expression is achieved by introducing a new cost function that measures pattern variation.Two array response control algorithms for pattern synthesis are proposed by combining the WORD algorithm and the oblique projection operation.The proposed algorithms can control the array responses of multiple points starting from an arbitrarily given weight vector.(3)A flexible array response control algorithm via oblique projection(FARCOP)is proposed.The proposed FARCOP algorithm stems from the adaptive array theory,and it can flexibly,precisely and simultaneously adjust the array response levels at multiple angles based on an arbitrarily given weight vector.(4)A new array response control algorithm named complex-coefficient weight vec-tor orthogonal decomposition(C~2-WORD)is proposed and its application to robust side-lobe control and synthesis in the presence of steering vector mismatch is investigated.The proposed algorithm is able to precisely control the upper boundary response level of a sidelobe point as desired.(5)A new method to synthesize high-performance beampatterns is presented by using linear fractional semidefinite relaxation(LFSDR)technique and quasi-convex op-timization approach.The proposed method performs well and is not limited to the array configurations and/or noise environments.(6)A geometric approach to fast array response adjustment with phase-only con-straint is proposed.The devised algorithm can precisely and rapidly adjust the array response of a given point by only tuning the excitation phases of a pre-assigned weight vector.The proposed algorithm provides an analytical solution and guarantees a precise phase-only adjustment without pattern distortion.(7)Two secure transmission algorithms for millimeter-wave wireless communica-tion are proposed.The proposed algorithms are computationally attractive and have ana-lytical solutions.Different from the existing works that are only feasible for the case of single-path mmWave channels,the proposed algorithms are applicable to more general multi-path channels.(8)A new method is presented to effectively estimate the direction-of-arrival(DOA)of a source signal and the phase error of a uniform linear array.Assuming that one sensor(except the reference one)has been calibrated,the proposed method appropriately reconstructs the data matrix and establishes a series of linear equations with respect to the unknown parameters through eigenvalue decomposition.The proposed scheme is further extended to the case of partly calibrated arrays with arbitrary geometries.