Robust Antenna Array Beamforming under Cycle Frequency Mismatch

Many algorithms exploiting the signal cyclostationarity have been shown to be effective in performing antenna array beamforming. However, these algorithms can not provide a unique weight vector for simultaneously extracting multiple signals of interest (SOIs) with distinct cycle frequencies (DCFs). They also suffer from severe performance degradation in the presence of a cycle frequency error (CFE). To simultaneously accommodate multiple SOIs with DCFs and alleviate the effects of cycle leakage due to finite data samples, we propose a cyclic sample matrix inversion (C-SMI) beamformer. To make the C-SMI beamformer robust against CFE, we present a novel objective function which is optimized by using a steepest-descent based algorithm to find the appropriate estimates of the true DCFs. The simulation results show the effectiveness of the robust C-SMI beamformer.