Abstract: This research investigates the digital-to-analog converter (DAC) free architecture for the digital reconfigurable intelligent surface (RIS) system, where the transmission lines are implemented for reflection coefficient (RC) control to reduce power consumption. In the proposed architecture, the radio frequency (RF) switch based phase shifter is considered. By using a single-pole four-throw (SP4T) switch to simultaneously control the RCs of a group of elements, a 2-bit phase shifter is realized for passive beam steering. A novel modulation scheme is developed to explore the cost effectiveness, which approaches the performance of traditional quadrature amplitude modulation (QAM). Specifically, to overcome the limitation of the phase shift bits, joint frequency-shift and phase-rotation operations are applied to the constellation points. The simulation and experimental results demonstrate that the proposed architecture is capable of providing an ideal transmission performance. Moreover, 64- and 256-QAM modulation schemes could be implemented by expanding the elements and phase bits.

免数模转换的数字可重构智能超表面架构

[1]Basar E, 2019. Transmission through large intelligent surfaces: a new frontier in wireless communications. European Conf on Networks and Communications, p.112-117.

[2]Chen DX, Yang WC, Che WQ, et al., 2022. Miniaturized wideband metasurface antennas using cross-layer capacitive loading. IEEE Antenn Wirel Propag Lett, 21(1):19-23.

[3]Chen J, Liang YC, Cheng HV, et al., 2023. Channel estimation for reconfigurable intelligent surface aided multi-user MIMO systems. IEEE Trans Wirel Commun, 22(10):6853-6869.

[4]Chen MZ, Tang WK, Dai JY, et al., 2022. Accurate and broadband manipulations of harmonic amplitudes and phases to reach 256 QAM millimeter-wave wireless communications by time-domain digital coding metasurface. Nat Sci Rev, 9(1):nwab134.

[5]Cui TJ, Liu S, Zhang L, 2017. Information metamaterials and metasurfaces. J Mater Chem C, 5(15):3644-3668.

[6]Dai JY, Tang WK, Zhao J, et al., 2019. Wireless communications through a simplified architecture based on time-domain digital coding metasurface. Adv Mater Technol, 4(7):1900044.

[7]Dai JY, Tang WK, Chen MZ, et al., 2021. Wireless communication based on information metasurfaces. IEEE Trans Microw Theory Tech, 69(3):1493-1510.

[8]Di BY, Zhang HL, Song LY, et al., 2020. Hybrid beamforming for reconfigurable intelligent surface based multi-user communications: achievable rates with limited discrete phase shifts. IEEE J Sel Areas Commun, 38(8):1809-1822.

[9]Du GH, Wang DD, Sun XF, et al., 2021. Design of a reflective metasurface for near-field focusing. IEEE Int Symp on Antennas and Propagation and USNC-URSI Radio Science Meeting, p.323-324.

[10]ElMossallamy MA, Zhang HL, Song LY, et al., 2020. Reconfigurable intelligent surfaces for wireless communications: principles, challenges, and opportunities. IEEE Trans Cogn Commun Netw, 6(3):990-1002.

[11]Gao X, Yang WL, Ma HF, et al., 2018. A reconfigurable broadband polarization converter based on an active metasurface. IEEE Trans Antenn Propag, 66(11):6086-6095.

[12]Hu S, Rusek F, Edfors O, 2018. Beyond massive MIMO: the potential of data transmission with large intelligent surfaces. IEEE Trans Signal Process, 66(10):2746-2758.

[13]Kundu NK, Mckay MR, 2021. Large intelligent surfaces with channel estimation overhead: achievable rate and optimal configuration. IEEE Wire Commun Lett, 10(5):986-990.

[14]Liu F, Guo JY, Zhao LY, et al., 2020. Dual-band metasurface-based decoupling method for two closely packed dual-band antennas. IEEE Trans Antenn Propag, 68(1):552-557.

[15]Liu YW, Liu X, Mu XD, et al., 2021. Reconfigurable intelligent surfaces: principles and opportunities. IEEE Commun Surv Tut, 23(3):1546-1577.

[16]Lou Q, Chen ZN, 2021. Sidelobe suppression of metalens antenna by amplitude and phase controllable metasurfaces. IEEE Trans Antenn Propag, 69(10):6977-6981.

[17]Luo JS, Wang FG, Wang SL, et al., 2021. Reconfigurable intelligent surface: reflection design against passive eaves-dropping. IEEE Trans Wirel Commun, 20(5):3350-3364.

[18]Minatti G, Faenzi M, Martini E, et al., 2015. Modulated metasurface antennas for space: synthesis, analysis and realizations. IEEE Trans Antenn Propag, 63(4):1288-1300.

[19]Nguyen NT, Vu QD, Lee K, et al., 2021. Spectral efficiency optimization for hybrid relay-reflecting intelligent surface. IEEE Int Conf on Communications Workshops, p.1-6.

[20]Rajabalipanah H, Abdolali A, Iqbal S, et al., 2021. Analog signal processing through space-time digital metasurfaces. Nanophotonics, 10(6):1753-1764.

[21]Sanchez JR, Rusek F, Edfors O, et al., 2019. An iterative interference cancellation algorithm for large intelligent surfaces. http://export.arxiv.org/abs/1911.10804

[22]Sanusi OM, Wang Y, Roy L, 2022. Reconfigurable polarization converter using liquid metal based metasurface. IEEE Trans Antenn Propag, 70(4):2801-2810.

[23]Taha A, Alrabeiah M, Alkhateeb A, 2021. Enabling large intelligent surfaces with compressive sensing and deep learning. IEEE Access, 9:44304-44321.

[24]Tang WK, Dai JY, Chen MZ, et al., 2019. Programmable metasurface-based RF chain-free 8PSK wireless transmitter. Electron Lett, 55(7):417-420.

[25]Varamini G, Keshtkar A, Naser-Moghadasi M, 2018. Miniaturization of microstrip loop antenna for wireless applications based on metamaterial metasurface. AEU Int J Electron Commun, 83:32-39.

[26]Wan ZW, Gao Z, Gao FF, et al., 2021. Terahertz massive MIMO with holographic reconfigurable intelligent surfaces. IEEE Trans Commun, 69(7):4732-4750.

[27]Ying KK, Gao Z, Lyu S, et al., 2020. GMD-based hybrid beamforming for large reconfigurable intelligent surface assisted millimeter-wave massive MIMO. IEEE Access, 8:19530-19539.

[28]Yuan XJ, Zhang YJA, Shi YM, et al., 2021. Reconfigurable-intelligent-surface empowered wireless communications: challenges and opportunities. IEEE Wirel Commun, 28(2):136-143.

[29]Zeng SH, Zhang HL, Di BY, et al., 2021. Reconfigurable intelligent surface (RIS) assisted wireless coverage extension: RIS orientation and location optimization. IEEE Commun Lett, 25(1):269-273.

[30]Zhang L, Chen XQ, Liu S, et al., 2018. Space-time-coding digital metasurfaces. Nat Commun, 9(1):4334.

[31]Zhang XG, Sun YL, Zhu BC, et al., 2022. A metasurface-based light-to-microwave transmitter for hybrid wireless communications. Light Sci Appl, 11(1):126.

[32]Zheng Q, Guo CJ, Ding J, 2018. Wideband metasurface-based reflective polarization converter for linear-to-linear and linear-to-circular polarization conversion. IEEE Antenn Wirel Propag Lett, 17(8):1459-1463.