Editorial

Linglong Dai, Chan-Byoung Chae, Shi Jin, Marco Di Renzo, Rui Zhang
2022 Intelligent and Converged Networks  
RIS), also known as intelligent reflecting surface or large intelligent surface, is an emerging new physical-layer technology in the field of wireless communications. The basic idea of RIS is to deploy a reconfigurable passive array in the environment to manipulate the propagation of electron-magnetic waves. RIS promises a new design paradigm for wireless communications, where the wireless propagation environment can be dynamically controlled, which is substantially different from the
more » ... al design that focuses only on the transmitter and receiver. For RIS-aided wireless communications, some of the current methodologies in conventional communication systems need to be revised, and some novel solutions are required to realize the potential benefits of the RIS. Although the number of publications about RIS has recently sharply increased, there are still many challenging issues to be extensively investigated, such as the RIS channel modeling, fundamental performance limits, the system design, joint optimization of the RIS and the transceivers, channel state information acquisition, and interdisciplinary applications. The goal of this Special Issue on "Reconfigurable Intelligent Surface Aided Wireless Communications" of Intelligent and Converged Networks (ICN) is to attract high-quality papers of original research on RIS-aided wireless communications. The response from the community to the call has been overwhelming. Many of the submissions are from the most well known research groups in the field. After a strict review process, we decided to accept 8 papers, which were selected based on the technical relevance and merits. This issue contains 8 papers, covering a wide selection of topics as follows. Motivated by the recent increasing interests in the field of RISs and the consequent pioneering concept of the RIS-enabled smart wireless environments, the first paper, entitled "Reconfigurable intelligent surfaces for wireless communications: Overview of hardware designs, channel models, and estimation techniques", is an RIS tutorial, which overviews the latest advances in RIS hardware architectures as well as the most recent developments in the modeling of RIS unit elements and RIS-empowered wireless signal propagation. The authors also present a thorough overview of the channel estimation approaches for RIS-empowered communications systems, which constitute a prerequisite step for the optimized incorporation of RISs in future wireless networks. Finally, this paper discusses the relevance of the RIS technology in the latest wireless standards, and highlights the current and future standardization activities for the RIS technology and the consequent RIS-empowered wireless networking approaches. The second paper, entitled "Reconfigurable intelligent surface-aided wireless communications: An overview", is also a tutorial. Specifically, different from the conventional active phased antenna array, there is no dedicated radio-frequency chain installed at the RIS to perform complex signal processing operations. Taking advantage of its working principle, RIS can be deployed in an indoor/outdoor environment to dynamically manipulate the propagation environment. This paper first reviews the latest advances in RIS, including the application scenarios,
doi:10.23919/icn.2022.0008 fatcat:ws2me52pivcnff3lq7vbuvw2hu