Blind adaptive wideband beamforming for circular arrays based on phase mode transformation

To recover the desired signals without the knowledge of its direction of arrival for a wideband array system is a difficult problem and a direct application of the convolutive blind source separation (BSS) algorithms will not work even for a small number of sensors. In this paper, a novel approach is proposed to solve this blind adaptive wideband beamforming problem based on a uniform circular array. The received array signals are first transformed into different phase modes and each phase mode output is then processed by a filter to achieve a frequency independent response. As a result, a set of instantaneous mixtures of the original source signals is obtained and the original wideband beamforming problem can be readily solved using the standard instantaneous BSS algorithms.