2021/04/01 by Shu Sun, Sun, Shu, Hangsong Yan +1 · 3 citations
Engineering · Materials Science · #Advanced Antenna and Metasurface Technologies #Advanced Wireless Communication Technologies #Emerging Technologies (cs.ET) #FOS: Computer and information sciences #FOS: Electrical engineering #Metamaterials and Metasurfaces Applications #Networking and Internet Architecture (cs.NI) #Signal Processing (eess.SP) #electronic engineering #information engineering
paper · pdf · doi:10.48550/arxiv.2105.15096
openalex publication_date 2021/04/01 · openalex created_date 2021/09/27 · openalex updated_date 2026/07/28
The reconfigurable intelligent surface (RIS) is an emerging promising candidate technology for future wireless networks, where the element spacing is usually of sub-wavelength. Only limited knowledge, however, has been gained about the spatial-temporal correlation behavior among the elements in an RIS. In this paper, we investigate the spatial-temporal correlation for an RIS-enabled wireless communication system. Specifically, a joint small-scale spatial-temporal correlation model is derived under isotropic scattering, which can be represented by a four-dimensional sinc function. Furthermore, based upon the spatial-only correlation at a certain time instant, an essential RIS property -- the spatial degrees of freedom (DoF) -- is revisited, and an analytical expression is propounded to characterize the spatial DoF for RISs with realistic hence non-infinitesimal element spacing and finite aperture sizes. The results are vital to the accurate evaluation of various system performance metrics.