Parafac methods for blind beamforming: multilinear ALS performance and CRB

Low-rank trilinear and quadrilinear decomposition is shown to underlie the basic model for deterministic blind beamforming (DBB) in the presence of incoherent multipath with small delay spread. Quadrilinear regression is proposed for simultaneously estimating all model parameters and compared to the column span method of van der Veen (1998). A derivation and discussion of pertinent Cramer-Rao bounds for the trilinear model, and comparison of trilinear regression performance to the CRB are also included. These are of interest beyond the application scope of this paper