Beyond Holographic Hybrid Precoding: New Role of Downlink Multiuser Interference

The reconfigurable holographic surface (RHS) designs precoding by controlling the amplitude of its radiation elements. The existing RHS-aided precoder treat multiuser interference as a harmful element. However, if the multiuser interference is constructively aligned to the desired signal, it becomes a beneficial element for improving signal’s receive-quality. In this work, we exploit the knowledge of the data to be transmitted and channel state information (CSI), for the purpose of interference utilization. A novel hybrid precoding is formulated for RHS multiuser systems, aiming for maximizing the lower bound of signal-to-interference-plus-noise ratio (SINR) of multiple users. To strike the balance between the complexity and system performance, the optimization problem is decoupled into two convex subproblems i.e., one for optimizing digital precoder and the other for optimizing holographic precoder. Finally, a novel constructive interference (CI) based holographic hybrid precoding algorithm is proposed, which iterates its digital and holographic precoders with a fast convergence rate. Simulation results demonstrate the superiority of the proposed algorithm for enhancing receiving performance against the benchmarks.