Reconfigurable Intelligent Surface-Based Wireless Communications: Antenna Design, Prototyping, and Experimental Results

One of the key enablers of future wireless communications is constituted by massive multiple-input multiple-output (MIMO) systems, which can improve the spectral efficiency by orders of magnitude. In existing massive MIMO systems, however, conventional phased arrays are used for beamforming. This method results in excessive power consumption and high hardware costs. Recently, reconfigurable intelligent surface (RIS) has been considered as one of the revolutionary technologies to enable energy-efficient and smart wireless communications, which is a two-dimensional structure with a large number of passive elements. In this paper, we develop a new type of high-gain yet low-cost RIS that bears 256 elements. The proposed RIS combines the functions of phase shift and radiation together on an electromagnetic surface, where positive intrinsic-negative (PIN) diodes are used to realize 2-bit phase shifting for beamforming. This radical design forms the basis for the world’s first wireless communication prototype using RIS having 256 two-bit elements. The prototype consists of modular hardware and flexible software that encompass the following: the hosts for parameter setting and data exchange, the universal software radio peripherals (USRPs) for baseband and radio frequency (RF) signal processing, as well as the RIS for signal transmission and reception. Our performance evaluation confirms the feasibility and efficiency of RISs in wireless communications. We show that, at 2.3 GHz, the proposed RIS can achieve a 21.7 dBi antenna gain. At the millimeter wave (mmWave) frequency, that is, 28.5 GHz, it attains a 19.1 dBi antenna gain. Furthermore, it has been shown that the RIS-based wireless communication prototype developed is capable of significantly reducing the power consumption.

*Promotional prize winner of the 2020 IEEE Access Best Multimedia Award (Part 1)

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Winners of the 2019 IEEE Access Best Multimedia Award (Part 2)

IEEE Access would like to congratulate the winners of the 2019 IEEE Access Best Multimedia Award (Part 2) and recipients of a $500 USD Amazon gift card for their fine contributions to IEEE Access. The full article entitled, “kNN-STUFF: kNN STreaming Unit for Fpgas” can be found by clicking here.

 

Winners of the 2019 IEEE Access Best Multimedia Award (Part 1)

IEEE Access would like to congratulate the winners of the 2019 IEEE Access Best Multimedia Award (Part 1) and recipients of a $500 USD Amazon gift card for their fine contributions to IEEE Access. The full article entitled, “Hidden Outlier Noise and its Mitigation” can be found by clicking here.

 

2018 IEEE Access Best Multimedia Award Part 2 Winners

IEEE Access would like to congratulate the winners of the 2018 IEEE Access Best Multimedia Award Part 2 and recipients of a $500 USD Amazon gift card for their fine contributions to IEEE Access. The full article entitled, “FPGA Acceleration for Computationally Efficient Symbol-Level Precoding in Multi-User Multi-Antenna Communication Systems” can be found by clicking here.

 

Most Cited Article of 2017: Index Modulation Techniques for Next-Generation Wireless Networks

What is index modulation (IM)? This is an interesting question that we have started to hear more and more frequently over the past few years. The aim of this paper is to answer this question in a comprehensive manner by covering not only the basic principles and emerging variants of IM, but also reviewing the most recent as well as promising advances in this field toward the application scenarios foreseen in next-generation wireless networks. More specifically, we investigate three forms of IM: spatial modulation, channel modulation and orthogonal frequency division multiplexing (OFDM) with IM, which consider the transmit antennas of a multiple-input multiple-output system, the radio frequency mirrors (parasitic elements) mounted at a transmit antenna and the subcarriers of an OFDM system for IM techniques, respectively. We present the up-to-date advances in these three promising frontiers and discuss possible future research directions for IM-based schemes toward low-complexity, spectrum- and energy-efficient next-generation wireless networks.

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