An Active Reconfigurable Intelligent Surface Utilizing Phase-Reconfigurable Reflection Amplifiers

Rao, Junhui; Zhang, Yujie; Tang, Shiwen; Li, Zan; Chiu, Chi-Yuk; Murch, R.D.

doi:10.1109/tmtt.2023.3237029

Cited by 32 publications

(7 citation statements)

References 37 publications

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“…To confirm the analysis conducted in Section II, especially (11), a relative path loss budget for the CA-RIS at 4 GHz is summarized in Table III. The measured gain of the amplifier is 20.1 dB.…”

Section: Discussionmentioning

confidence: 78%

Active Reconfigurable Intelligent Surface: Fully-Connected or Sub-Connected?

et al. 2022

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Reconfigurable intelligent surfaces (RISs) are promising candidate for the 6G communication. Recently, active RIS has been proposed to compensate the multiplicative fading effect inherent in passive RISs. However, conventional distributed active RISs, with at least one amplifier per element, are costly, complex, and power-intensive. To address these challenges, this paper proposes a novel architecture of active RIS: the centralized active RIS (CA-RIS), which amplifies the energy using a centralized amplifying reflector to reduce the number of amplifiers. Under this architecture, only as low as one amplifier is needed for power amplification of the entire array, which can eliminate the mutual-coupling effect among amplifiers, and significantly reduce the cost, noise level, and power consumption. We evaluate the performance of CA-RIS, specifically its path loss, and compare it with conventional passive RISs, revealing a moderate amplification gain. Furthermore, the proposed CA-RIS and the path loss model are experimentally verified, achieving a 9.6 dB net gain over passive RIS at 4 GHz. The CA-RIS offers a substantial simplification of active RIS architecture while preserving performance, striking an optimal balance between system complexity and the performance, which is competitive in various scenarios.

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Section: Discussionmentioning

confidence: 78%

Active Reconfigurable Intelligent Surface: Fully-Connected or Sub-Connected?

et al. 2022

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“…The unit-modulus reflection coefficient can be realized through a purely reactive RIS load [2], [8], [13], [22], [29]. • Re(Z RIS ) < 0: This yields an amplitude gain |Θ| > 1 which is known as the active RIS [30]. Several technologies can realize a negative resistance.…”

Section: A Functional Principle Of Rismentioning

confidence: 99%

Localization Coverage Analysis of THz Communication Systems with a 3D Array

Zheng

Ballal

Chen

et al. 2022

GLOBECOM 2022 - 2022 IEEE Global Communications Conference

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This paper considers the problem of estimating the position and orientation of a user equipped with a threedimensional (3D) array receiving downlink far-field THz signals from multiple base stations with known positions and orientations. We derive the Cramér-Rao Bound for the localization problem and define the coverage of the considered system. We compare the error lower bound distributions of the conventional planar array and the 3D array configurations at different user equipment (UE) positions and orientations. Our numerical results obtained for array configurations with an equal number of elements show very limited coverage of the planar-array configuration, especially across the UE orientation range. Conversely, a 3D array configuration offers an overall higher coverage with minor performance loss in certain UE positions and orientations.

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“…RIS enabled wireless communication systems contribute to overall system performance improvement by mitigating the effects of fading [7]. In [8], an active RIS has been implemented using phase reconfigurable reflection amplifiers. The results have been investigated through a physical experiment setup.…”

Section: Introductionmentioning

confidence: 99%

Phase Shift Optimization for RIS Enabled PNC System With Multiple Antennas

İlgüy,

Özbek,

Musavian

et al. 2024

IEEE Access

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Reconfigurable intelligent surfaces (RISs) have been developed to exploit the stochastic characteristics of the propagation environment. On the other hand, the integration of wireless physical network coding (PNC) and multiple antennas yields notable enhancements in system performance. This paper presents a multi-user system, employing RIS enabled PNC alongside multiple antennas to minimize both latency and error probability. Our aim is to establish reliable communication between the user pairs, which communicate through a base station (BS) via RIS. Therefore, the reflecting coefficients including both phases and amplitudes of the RISs are optimized by using the alternating direction method of multipliers (ADMM) algorithm for both single and multiple RIS cases. Extensive results are presented to compare the proposed algorithm with random phase shift, network coding (NC) and the search algorithm to illustrate the superiority of the proposed method.

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An Active Reconfigurable Intelligent Surface Utilizing Phase-Reconfigurable Reflection Amplifiers

Cited by 32 publications

References 37 publications

Active Reconfigurable Intelligent Surface: Fully-Connected or Sub-Connected?

Active Reconfigurable Intelligent Surface: Fully-Connected or Sub-Connected?

Localization Coverage Analysis of THz Communication Systems with a 3D Array

Phase Shift Optimization for RIS Enabled PNC System With Multiple Antennas

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