Trellis Exploration Algorithm Aided Unitary Precoder Design for Maximizing MIMO Capacity With Limited Feedback

In this letter, we present a novel approach to determine limited feedback-based unitary precoder for maximizing single user (SU)-MIMO capacity. Specifically, a polyphase unitary precoding matrix is custom designed via the trellis exploration algorithm employing system capacity as the metric to maximize. Since the trellis exploration algorithm operates on a finite set of phases, information regarding the optimal precoder is fed back to the transmitter using a limited number of bits.