Exploiting Negative Feedback Information for One-Bit Feedback Beamforming Algorithm

In this paper a hybrid one-bit feedback algorithm is proposed to achieve carrier phase alignment at the receiver for distributed transmit beamforming. The proposed iterative algorithm employs two schemes to speed up the convergence process, which exploit negative feedback information in a single time slot (Scheme 1) and in successive time slots (Scheme 2) respectively, whereas previously proposed algorithms in the literature discard this information. We show that the proposed algorithm yields a significant improvement in the convergence speed compared to the original algorithm. Furthermore, we modify the proposed algorithm to be capable of tracking time-varying channels which have variable rates of phase drift. The modified hybrid algorithm has the ability to adjust perturbation sizes adaptively without the knowledge of channel state information and is suited for practical implementations.