Full Duplex Hybrid A/D Beamforming with Reduced Complexity Multi-Tap Analog Cancellation

Although the hardware complexity of the analog self-interference canceller in emerging full duplex Multiple Input Multiple Output (MIMO) designs does not scale with the number of transceiver antennas, exploiting the benefits of analog cancellation in massive MIMO systems with dozens of antennas is still quite impractical. Hybrid Analog and Digital (A/D) beamforming architectures have been lately considered as a candidate technology for realizing massive MIMO transceivers with very large number of antenna elements, but with much fewer numbers of Radio Frequency (RF) chains. In this paper, we present a novel architecture for full duplex hybrid A/D transceivers including multi-tap analog cancellation with reduced number of taps and simple multiplexers for efficient signal routing among the transceiver RF chains. Capitalizing on the proposed transceiver architecture, we present a joint design of analog cancellation and A/D beamforming with the objective to maximize the full duplex rate performance. Representative computer simulation results on a millimeter wave channel model demonstrate the effectiveness of the proposed architecture and algorithmic framework for enabling simultaneous uplink and downlink communications with reduced complexity analog cancellation.