Reconfigurable Intelligent Surface

Reconfigurable intelligent surfaces (RISs) are arrays of passive elements that can dynamically control the reflection of electromagnetic waves, improving wireless communication performance. Current research focuses on optimizing RIS configurations for various applications, employing deep reinforcement learning (DRL) algorithms like DDPG and SAC, and meta-learning approaches to address complex optimization problems in multi-user and multi-hop scenarios. This technology holds significant promise for enhancing spectral and energy efficiency in 5G and beyond, particularly in challenging environments like dense urban areas and indoor settings, by improving signal strength and coverage. The development of efficient channel estimation techniques and robust designs that account for hardware impairments are also key research areas.