A Novel Hybrid Beamformer Design for Massive MIMO Systems in 5G

Abstract

Modern communication systems use multiple antennas at the transmitter and receiver for increasing the user data rate and connection reliability. This comes at the cost of increased hardware and signal processing complexity. Hybrid beamformers, which are combinations of the analog and digital beamformers, offer a good trade-off between the hardware, signal processing complexity and performance. The analog beamformers operate on the radio frequency signals while the digital beamformers operate on the base-band signals. Unlike the fully digital or fully analog beamformers, the weights computation for the hybrid beamformers is more complicated and it requires a solution to a multi-parameter, non-convex optimization problem. This paper proposes a novel, simple-to-implement procedure, which addresses the drawbacks in the existing literature. The proposed beamformer design is addressed in three simple steps namely, transmit-only, receive-only and combined transmit and receive hybrid beamformers. The utility of the design procedures is illustrated in the context of the 5G massive MIMO beamformer, where the hardware complexity for a fully digital beamformer is not economically feasible. Numerical results are provided to support the theory.