Experimental and theoretical comparison of some algorithms for beamforming in single receiver adaptive arrays
1991 (English)In: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 0096-1973, Vol. 39, no 1, 21-28 p.Article in journal (Refereed) Published
Adaptive null steering in single receiver adaptive arrays is discussed. The single receiver structure allows only output power for a given set of weights to be measured. The problem, then, is to adaptively adjust the weights of the antenna array, based on output power measurements only, so as to reject interference signals while maintaining a fixed response in a given look direction. Current least-mean-square (LMS)-based iterative techniques use perturbations of the beamformer weights to obtain an estimate of the gradient of a given cost (power) function in order to update an initial guess. The key idea of this work is to determine the optimal beamformer weights in a single step, by estimating the covariance matrix of the array sensor outputs using a weight perturbation technique. Based on this covariance matrix estimate, three different approaches for finding the beamformer weights are studied. The first corresponds to a sample matrix inversion (SMI) scheme, with the sample covariance matrix replaced by the one obtained from the perturbation estimation method, while in the second approach the weights are determined using an eigenvalue decomposition of the covariance matrix estimate. In the third approach the directions-of-arrival (DOAs) of the incoming wavefronts are first estimated, and then, in a second step, the beamformer weights are calculated from the DOA estimates. The advantage of the third approach is that this method is not affected by correlation between the different sources. In comparison to iterative techniques, the approach offers much faster beamforming, albeit at the expense of increased susceptibility to unmodeled characteristics.
Place, publisher, year, edition, pages
1991. Vol. 39, no 1, 21-28 p.
Direction Finding Systems, Mathematical Techniques--Algorithms, Systems Science and Cybernetics--Adaptive Systems, Beam Forming, Covariance Matrix Based Methods, Least Mean Square Iteration, Null Steering, Single Receiver Adaptive Arrays, Antennas
IdentifiersURN: urn:nbn:se:kth:diva-55441DOI: 10.1109/8.64430ISI: A1991EQ58100004OAI: oai:DiVA.org:kth-55441DiVA: diva2:471581
QC 201201042012-01-022012-01-022013-09-05Bibliographically approved