Performance analysis of metasurface-based spatial multimode transmission for 6G wireless communications
Ju Yong Lee, Seung-Won Keum, Sang Min Oh, Dang-Oh Kim, Dong-Ho Cho
TL;DR
This work analyzes how metasurface-based spatial multimode transmission can harness near-field (Fresnel) space in 6G by establishing Fourier-transform-like relations between spatial signals on metasurfaces. It derives power conservation and modal limits under aligned and misaligned configurations, and proposes a low-complexity three-metasurface system to realize two consecutive Fourier transforms for signal recovery. The study provides explicit phase designs, power relations, and maximum spatial multimode expressions for both rectangular and Gaussian inputs, with numerical validation at 30 GHz. The results demonstrate the potential to encode multiple spatial streams with metasurface apertures while quantifying degradation due to misalignment and the benefits of RIS-assisted three-surface architectures for practical high-capacity links.
Abstract
In 6th generation wireless communication technology, it is important to utilize space resources efficiently. Recently, holographic multiple-input multiple-output (HMIMO) and meta-surface technology have attracted attention as technologies that maximize space utilization for 6G mobile communications. However, studies on HMIMO communications are still in an initial stage and its fundamental limits are yet to be unveiled. It is well known that the Fourier transform relationship can be obtained using a lens in the optical field, but research to apply it to the mobile communication field is in the early stages. In this paper, we show that the Fourier transform relationship between signals can be obtained when two metasurfaces are aligned or unaligned, and analyze the transmission and reception power, and the maximum number of spatial multimodes that can be transmitted. In addition, to reduce transmission complexity, we propose a spatial multimode transmission system using three metasurfaces and analyze signal characteristics on the meta-surfaces. In numerical results, we provide the performance of spatial multimode transmission in case of using rectangular and Gaussian signals.