Holographic Beamforming Design for RHS-Assisted MU-MISO Systems with One-Bit DACs

Reconfigurable holographic surfaces (RHSs) can generate the desired directional beam by controlling the radiation amplitude of reference wave, and thus is an effective alternative to conventional analogue beamforming architecture. In this paper, we investigate the RHS-aided downlink multiuser multiple-input-single-output system with one-bit digital-to-analogue converters. Specifically, we aim to minimize the mean-square error by alternately optimizing the one-bit precoding vector and the holographic beamforming matrix. The alternating direction method of multipliers algorithm is employed to optimize the one-bit nonlinear precoding vector, and the projected gradient decent method, the mathematical programming with equilibrium constraints-alternating direction method, and the Riemannian conjugate gradient method are utilized to design the holographic beamforming matrix with continuous amplitude, binary amplitude, and Lorentzian-constrained phase, respectively. Finally, the effectiveness of the proposed method is demonstrated by computer simulations.