Exploiting RIS’s Role for Energy Efficiency and Security in Cell-Free Massive MIMO Networks

Reconfigurable intelligent surface (RIS) has shown significant advantages in improving energy efficiency (EE) and ensuring secure communications in cell-free massive multiple-input multiple-output (CF mMIMO) networks. In this letter, in order to enable RIS to fully play its role and explore the inherent advantages of RIS, we design a joint phase adjustment and power control scheme to optimize the EE of network, while coping with pilot attacks. An Improved DDPG-PER algorithm, which integrates batch normalization (BN), prioritized experience replay (PER) and deep deterministic policy gradient (DDPG), is devised to efficiently address the optimization problem while enhancing learning capability. The simulation results show that our proposed scheme enhances both energy efficiency and security.