N. Rajatheva et al., "White paper on broadband connectivity in 6G, " 6G Res. Vis., Uni. Oulu, no. 10, pp. 1-46, June 2020.
M. Jian et al., "Reconfigurable intelligent surfaces for wireless communications: Overview of hardware designs, channel models, and estimation techniques, " Intell. Converged Netw., vol. 3, no. 1, pp. 1-32, Mar. 2022.
C. Huang et al., "Reconfigurable intelligent surfaces for energy efficiency in wireless communication, " IEEE Trans. Wireless Commun., vol. 18, no. 8, pp. 4157-4170, Aug. 2019.
E. Björnson et al., "Intelligent reflecting surface versus decode-Andforward: How large surfaces are needed to beat relaying?" IEEE Wireless Commun. Lett., vol. 9, no. 2, pp. 244-248, Feb. 2020.
Z. Abdullah et al., "A hybrid relay and intelligent reflecting surface network and its ergodic performance analysis, " IEEE Wireless Commun. Lett., vol. 9, no. 10, pp. 1653-1657, Oct. 2020.
M. Obeed and A. Chaaban, "Joint beamforming design for multiuser MISO downlink aided by a reconfigurable intelliegent surface and a relay, " IEEE Trans. Wireless Commun., to appear (early access), DOI: 10.1109/TWC.2022.3164903.
I. Yildirim et al., "Hybrid RIS-empowered reflection and decode-Andforward relaying for coverage extension, " IEEE Commun. Lett., vol. 25, no. 5, pp. 1692-1696, 2021.
Z. Kang et al., "IRS-Aided wireless relaying: Deployment strategy and capacity scaling, " IEEE Wireless Commun. Lett., vol. 11, no. 2, pp. 215-219, Feb. 2022.
Z. Abdullah et al., "Double-RIS communication with DF relaying for coverage extension: Is one relay enough?" in IEEE Int. Conf. Commun. (ICC), May 2022, pp. 2639-2644.
E. Björnson and L. Sanguinetti, "Rayleigh fading modeling and channel hardening for reconfigurable intelligent surfaces, " IEEE Wireless Commun. Lett., vol. 10, no. 4, pp. 830-834, Apr. 2020.
A. Taha et al., "Enabling large intelligent surfaces with compressive sensing and deep learning, " IEEE Access, vol. 9, pp. 44 304-44 321, Mar. 2021.
O. T. Demir and E. Björnson, "Is channel estimation necessary to select phase-shifts for RIS-Assisted massive MIMO?" IEEE Trans. Wireless Commun., to appear (early access), DOI:10.1109/TWC.2022.3177700.
"Report on the comparison between ideal HyperSurface (HSF)s and the manufactured prototypes, " VISORSURF Project, Tech. Rep., Dec. 2020. [Online]. Available: https://ec.europa.eu/research/participants/documen ts/downloadPublic?documentIds=080166e5d7993c7d&appId=PPGMS
Z. Abdullah et al., "Impact of phase-noise and spatial correlation on double-RIS-Assisted multiuser MISO networks, " IEEE Wireless Commun. Lett., vol. 11, no. 7, pp. 1473-1477, July 2022.
