Implementation scheme of RIS-NOMA communication based on environment-aware codebook

To address the joint optimization of dynamic channel state information acquisition and resource allocation in reconfigurable intelligent surface (RIS)-assisted non-orthogonal multiple access (NOMA) communication systems, an implementation scheme of RIS-NOMA communication scheme based on environment-aware codebook was proposed. The proposed scheme adapted the existing environment-aware codebook scheme to the RIS-NOMA scenario. In the offline phase, a virtual channel set was generated based on statistical channel state information, and RIS phase shifts, beamforming, and power allocation were jointly designed using an alternating optimization algorithm to create an offline codebook. In the online phase, configurations were selected from the codebook to maximize the achievable rate, enabling low-complexity dynamic resource allocation. Additionally, the theoretical performance of the environment-aware codebook model was analyzed under channel estimation errors. Numerical simulation results demonstrated that the proposed scheme achieved a high sum rate while ensuring user fairness and effectively managing multi-user interference. Compared to environment-aware codebook-based RIS-assisted multiple-input single-output communication, the proposed scheme achieves a sum rate improvement of 20% to 40%, particularly highlighting the advantages of NOMA systems in multi-user multiplexing and power allocation. The study provides theoretical support and design references for the practical deployment of RIS-NOMA systems.