SI-based hybrid precoder for mmWave massive MU-MIMO systems

This paper proposes a hybrid precoder based on low-cost and high-energy-efficient analog components. The considered hardware architecture requires switches and inverters instead of phase shifters, which significantly reduces the freedom degrees for the analog signal processing in the compensation for reducing the manufacturing cost and power consumption. Since the hardware architecture is based on switches, the proposed analog beamformer performs an effective and low computational complexity switching algorithm, which aims to maximize the system's sum rate. On the other hand, the proposed baseband beamformer performs a twofold procedure that eliminates the inter-user interference and increases the signal-to-noise ratio, further increasing the systems' sum rate. Simulation results show that although the freedom degrees to generate the analog beamformer are low, the proposed method overcomes hybrid precoders with phase shifters of up to 3 bits resolution in terms of BER, sum-rate, and energy efficiency.