Beamforming in the presence of correlated arrivals using structured correlation matrix

Expressions are derived for the SNR (signal-to-noise-ratio) at the output of two antenna array processors in the presence of correlated arrivals, and the effect on the output SNR of the magnitude and the phase of the correlation, the number of elements in the array, the direction of the level of the interference source, and the level of the uncorrelated noise is investigated. The two processes considered are the optimal element space processor (ESP) and the optimal postbeamformer interference canceller (PIC). The PIC processes the signal by forming two beams and adjusting the weights of one beam, in contrast to the ESP where the signals from all the elements are weighted and all the weights are adjusted. A method is proposed for decorrelating the correlated sources, and an analytical expression is derived to show the decorrelation effect of the proposed technique for a line array of equispaced elements. Numerical examples are included