Identifiability results for blind beamforming in incoherent multipath with small delay spread

Several explicit identifiability results are derived for deterministic blind beamforming in incoherent multipath with small delay spread. For example, it is shown that if the sum of spatial and fractional sampling diversities exceeds two times the total number of paths, then identifiability can be guaranteed even for one symbol snapshot. The tools come from the theory of low-rank three-way array decomposition (commonly referred to as parallel factor analysis (PARAFAC) and data smoothing in one and two dimensions. New results regarding the Kruskal-rank of certain structured matrices are also included, and they are of interest in their own right.