Sustainable Multi-User Communication with Reconfigurable Intelligent Surfaces in 5G Wireless Networks and Beyond

Reconfigurable intelligent surfaces show huge potential to provide significant performance improvement for wireless communications. Low cost and power consumption, lightweight, and flexible deployment make them perfect for integration within the 5G mobile network infrastructure. However, the problems of multipath fading interference and radiation losses are prominent at mmWave frequencies. To enable massive connectivity and low-latency communications, one should tackle and eventually exploit the randomness of the real-life wireless propagation channels. In order to enable multi-User Equipment communication broadcasting, achieving simultaneous beamforming on multiple beams is of paramount importance. This paper provides a strategy to control the propagation channel via reconfigurable intelligent surfaces and generate multiple pencil beams for concurrent user access at mmWave frequencies. Compared to simultaneous amplitude and phase surface reconfiguration, this technique requires only phase coding to engineer multi-beamforming dynamically. The proposed technique creates an arbitrary number of beams that are stable among a wide frequency band.