Performance comparison of limited feedback codebook-based downlink beamforming schemes for Distributed Antenna Systems

In this paper, we consider limited feedback codebook-based downlink beamforming involving two remote antenna units with two antennas each transmitting to a single-antenna mobile terminal. A central unit to which the two remote antenna units are connected enables centralized joint beamforming. We consider different practical channel scenarios that may arise in distributed antenna systems and gauge the performance of the Grassmannian, Kerdock and Unitary-DFT codebooks. We then compare the performance when modified code books that exploit information such as transmit antenna correlation are used. We conclude the paper by listing the strengths and drawbacks of each of the three codebooks.