High order noncircularity restoral diagonal loading robust adaptive beamforming: HNRDL

A robust adaptive beamformer utilizing noncircularity restoral of the signal-of-interest (SOI) is proposed. In contrast to the existing second-order noncircularity restoral schemes, this new robust beamformer, called HNRDL, is applicable to the case of higher than second-order noncircular SOI, such as QPSK signal and QAM signal. Unlike the popular uncertainty-set schemes, the diagonal loading level in HNRDL can be determined adaptively which involves no user-parameters. Simulation results are included to illustrate the robust filtering performance of the proposed HNRDL beamformer.