Trends, Challenges, and Key Technologies of Beam-Space Multiplexing Based on Metasurfaces

Beam-space multiplexing, recognized as a pivotal technology within the Third Generation Partnership Project (3GPP) standard, has been already adopted to simultaneously obtain the array gain and the multiplexing gain in fourth generation (4G) and fifth generation (5G) systems. This technique is expected to play a significant role in the forth-coming sixth generation (6G) networks. This article proposes beam-space multiplexing based on metasurfaces for 6G, aimed at enhancing multilayer data transmission on the transmitter side. Specifically, we delve into the foundational theoretical analysis of beam-space multiplexing and beam-space multiplexing based on metasurface. This article covers the signal model, hardware structure, working principle, possible deployment architecture and so on. Comprehensive application scenarios are introduced from different perspectives. The design methodologies and the actual performance metrics from our developed prototype platform equipped with metasurface are provided. Finally, future research directions and trends for beam-space multiplexing based on metasurface are highlighted.