Sharing the Surface: RIS-aided Distributed Mechanism Design for Hybrid Beamforming in Multi-cell Multi-user Networks

Reconfigurable intelligent surface (RIS) as a new antenna technology has triggered a revolution in multi-antenna multi-user networks due to its capability of intelligently reconstructing the propagation environments passively without extra hardware or power consumption. In this paper, we propose the RIS-aided multi-cell multi-user networks where neighbouring BSs are allowed to share the same RIS to mitigate inter-cell interference via RIS-based hybrid beamforming. For sum-rate maximization, a near-optimal distributed algorithm is designed where the BSs negotiate with each other to reach a consensus on the RIS-based beamforming without revealing any information of their serving users. Simulation results show that the proposed scheme achieves a close performance compared to the centralized scheme, and much better than the traditional no-RIS scheme.