Title :
Limitations and capabilities of frequency domain broadband constrained beamforming schemes
Author :
Godara, Lal C. ; Jahromi, M.R.S.
Author_Institution :
Sch. of Electr. Eng., New South Wales Univ., Kensington, NSW, Australia
fDate :
9/1/1999 12:00:00 AM
Abstract :
Time domain processing of broadband signals using an array of sensors is normally carried out by a transversal filter, and the filter coefficients are adjusted by solving a constrained beamforming problem that requires manipulation of matrices of dimension LJ×LJ with L denoting the number of sensors in the array and J denoting the filter length. This paper studies a frequency domain method to compute the coefficients of transversal filter, compares its performance, sensitivity to the look direction, and computational efficiency with that of the direct method, and shows how the computational saving increases using the frequency domain method as the number of elements and the filter length are increased. The paper presents a number of techniques that exploit the inherent structure present in the frequency domain method to reduce the computation load and shows that the real-time computational saving of the order of 12520 folds is possible for an array of 100 elements using a tap delay line filter of 100 taps. The paper demonstrates that a beamformer using this method is able to produce more output SNR with less computation time than the one using the normal time domain method
Keywords :
array signal processing; delay lines; filtering theory; frequency-domain analysis; matrix algebra; parallel processing; broadband signals; computation load reduction; computation time; computational efficiency; direct method; filter length; frequency domain broadband constrained beamforming; look direction sensitivity; matrix dimension; output SNR; parallel processing; real-time computational saving; sensor array; tap delay line filter; time domain processing; transversal filter coefficients; Array signal processing; Broadband antennas; Computational efficiency; Frequency domain analysis; Interference; Sensor arrays; Signal processing; Signal to noise ratio; Time division multiplexing; Transversal filters;
Journal_Title :
Signal Processing, IEEE Transactions on