Beamforming Optimization for Reconfigurable Intelligent Surface With Power Splitting Aided Broadcasting Networks

Reconfigurable intelligent surface (RIS) has emerged as a promising technology for the 6G networks. In this article, we study a RIS with power splitting aided broadcasting network where one access point (AP) transmits identical messages to multiple users. The RIS is capable of reflecting a part of the incident signals to assist the AP and harvesting energy from the other part to achieve power self-sustainability by controlling reflect amplitude coefficients. We aim at minimizing the AP transmit power while ensuring the quality of service at users and the self-sustainability of the RIS by optimizing the AP transmit beamforming vector and the RIS reflect beamforming matrix which involves the reflect amplitude and phase shift coefficients. To tackle the beamforming optimization problem which is non-convex, an algorithm is proposed by employing the block coordinate descent, convex approximation and alternating direction method of multipliers techniques. Simulation results demonstrate the effectiveness of the proposed algorithm.