【Title】Frequency-invariant robust adaptive beamforming based on interference covariance matrix reconstruction (2014 No.4) 

【Author】FAN Zhan; LIANG Guolong 

【Abstract】Consider the problems of frequency-invariant beam pattern optimization and robustness in broadband beamforming. Firstly, a global optimization algorithm, which is based on phase compensation of the array manifolds, is used to construct the frequency-invariant beam pattern. Compared with some methods presented recently, the proposed algorithm is not only available to get the global optimal solution, but also simple for physical realization. Meanwhile, a robust adaptive broadband beamforming algorithm is also derived by reconstructing the covariance matrix.The essence of the proposed algorithm is to estimate the space-frequency spectrum using Capon estimator firstly, then integrate over a region separated from the desired signal direction to reconstruct the interference-plus-noise covariance matrix, and finally calculate the adaptive beamformer weights with the reconstructed matrix. The design of beamformer is formulated as a convex optimization problem to be solved. Simulation results show that the performance of the proposed algorithm is almost always close to the optimal value across a wide range of signal to noise ratios.