Blind adaptive polarization filtering based on oblique projection

Polarization filtering has attracted a great interests for it can be used to solve problems of signal separation and interference suppression those are difficult to process in the time, frequency and spatial domains. Polarization information of both target signal and interference are needed to design the polarization filter in the conventional method, while exact estimation of the polarization information is difficult and some estimation errors also render poor performance of polarization filtering. Based on the superior merits of oblique projection in signal processing applications, a novel blind adaptive oblique projection polarization filtering (OPPF) algorithm is proposed in this paper. The pseudo-inverse of the covariance matrix obtained from the received signal and the polarization state of target signal are used to construct the vector of polarization filtering, and the estimation of interference polarization is replaced by the power estimation of AWGN. Detailed analysis and deduction are made, and simulation and numerical results show the effectiveness of the proposed algorithm, which is in-line-with the theory of polarization filtering.