Abstract
The reconfigurable intelligent surface (RIS) has been recognized as an essential enabling technology for sixth-generation (6G) mobile communication networks. An RIS comprises a large number of small and low-cost reflecting elements whose parameters can be dynamically adjusted with a programmable controller. Each of these elements can effectively reflect a phase-shifted version of the incident electromagnetic wave. By configuring the wave phases in real time, the propagation environment of the information-bearing signals can be dynamically manipulated to enhance communication reliability, boost transmission rate, expand cellular coverage, and strengthen communication security. In this study, we provide an overview on RIS-assisted wireless communications. Specifically, we elaborate on the state-of-the-art enabling techniques for the RIS technology as well as their corresponding substantial benefits from the perspectives of RIS reflection and RIS modulation. With these benefits, we envision the integration of RISs into emerging applications for 6G. In addition, communication security is of unprecedented importance in future 6G networks with ubiquitous wireless services in multifarious verticals and areas. We highlight potential contributions of RISs to physical-layer security, in terms of secrecy rate and secrecy outage probability, exemplified by a typical case study from both theoretical and numerical aspects. Finally, we discuss challenges and opportunities on the deployment of RISs in practice to motivate future research.
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Acknowledgements
This work was supported in part by Ministry of Education, Singapore, under its MOE Tier 2 (Grant No. MOE-T2EP50220-0019), EU H2020 RISE-6G project (Grant No. 10101701), National Key R&D Program of China (Grant No. 2021YFA1000500), National Natural Science Foundation of China (Grant No. 62101492), Zhejiang Provincial Natural Science Foundation of China (Grant No. LR22F010002), National Natural Science Fund for Excellent Young Scientists Fund Program (Overseas), Zhejiang University Education Foundation Qizhen Scholar Foundation, and Fundamental Research Funds for the Central Universities (Grant No. 2021FZZX001-21). The work of M. DI RENZO was supported in part by the European Commission through H2020 ARIADNE Project (Grant No. 871464) and through H2020 RISE-6G Project (Grant No. 101017011). Any opinions, findings and conclusion or recommendations expressed in this material are those of the authors and do not reflect the views of the Ministry of Education, Singapore.
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Xu, J., Yuen, C., Huang, C. et al. Reconfiguring wireless environments via intelligent surfaces for 6G: reflection, modulation, and security. Sci. China Inf. Sci. 66, 130304 (2023). https://doi.org/10.1007/s11432-022-3626-5
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DOI: https://doi.org/10.1007/s11432-022-3626-5