Beamspace MIMO transceivers for low-complexity and near-optimal communication at mm-wave frequencies

Multiple-input multiple-output (MIMO) systems that exploit multi-antenna arrays and millimeter-wave systems operating in the 30-300GHz band offer synergistic opportunities for meeting the exploding data requirements of wireless networks. While combining these technologies offers the advantages of high-dimensional MIMO, it increases transceiver complexity dramatically in conventional MIMO approaches due to the large number of antennas required for optimal performance. On the other hand, the dimension of the communication subspace is typically much smaller than the system dimension in practice. By multiplexing data onto highly directional orthogonal beams, beamspace MIMO (B-MIMO) provides direct and near-optimum access to the low-dimensional communication subspace and dramatically lowers transceiver complexity when realized with analog beamforming. In this paper we present and analyze the capacity of several low-complexity B-MIMO transceivers for realizing multi-Gigabits/s speeds.