Integrated Sensing and Communication with Reconfigurable Intelligent Surfaces: Opportunities, Applications, and Future Directions

Liu, Rang; Li, Ming; Luo, Honghao; Liu, Qian; Swindlehurst, A. Lee

doi:10.1109/mwc.002.2200206

Cited by 54 publications

(11 citation statements)

References 14 publications

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“…Note that the expression for ĝ1 in (10) is the same as in (5). This shows that when B H 1 B 2 = 0, the MML in (5) coincides with the ML estimator; that is, the misspecified model is sufficient when the configuration sequences are designed to alleviate pilot interference because the missing terms anyway vanish in the receiver processing.…”

Section: B Case 2: the Riss Adopt Different Configuration Sequencesmentioning

confidence: 87%

“…On the other hand, the addition of RISs to existing systems introduces new design and operational challenges [10]. For example, the length of the pilot signal required by a single UE is proportional to the number of RIS elements (e.g., tens or hundreds), because the RIS must change its configuration to explore all channel dimensions [11], [12].…”

Section: Introductionmentioning

confidence: 99%

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Impact of Pilot Contamination Between Operators With Interfering Reconfigurable Intelligent Surfaces

Gürgünoğlu,

Björnson,

Fodor

2023

2023 IEEE International Black Sea Conference on Communications and Networking (BlackSeaCom)

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In this paper, we study a new kind of pilot contamination appearing in multi-operator reconfigurable intelligent surfaces (RIS) assisted networks, where multiple operators provide services to their respective served users. The operators use dedicated frequency bands, but each RIS inadvertently reflects the transmitted uplink signals of the user equipment devices in multiple bands. Consequently, the concurrent reflection of pilot signals during the channel estimation phase introduces a new inter-operator pilot contamination effect. We investigate the implications of this effect in systems with either deterministic or correlated Rayleigh fading channels, specifically focusing on its impact on channel estimation quality, signal equalization, and channel capacity. The numerical results demonstrate the substantial degradation in system performance caused by this phenomenon and highlight the pressing need to address interoperator pilot contamination in multi-operator RIS deployments. To combat the negative effect of this new type of pilot contamination, we propose to use orthogonal RIS configurations during uplink pilot transmission, which can mitigate or eliminate the negative effect of inter-operator pilot contamination at the expense of some inter-operator information exchange and orchestration.

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Section: B Case 2: the Riss Adopt Different Configuration Sequencesmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Impact of Pilot Contamination Between Operators With Interfering Reconfigurable Intelligent Surfaces

Gürgünoğlu,

Björnson,

Fodor

2023

2023 IEEE International Black Sea Conference on Communications and Networking (BlackSeaCom)

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“…Numerous studies have demonstrated that combining RIS with other emerging technologies can improve the signal propagation environment [10], [11]. There were also many studies on the integration of RIS and ISAC [12], [13]. For the RIS-aided ISAC system, two main scenarios have been typically considered [14].…”

Section: Index Termsmentioning

confidence: 99%

Active RIS Aided Integrated Sensing and Communication Systems

Yu¹,

Gui²,

Hong³

et al. 2023

Preprint

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This paper considers an active reconfigurable intelligent surface (RIS)-aided integrated sensing and communication (ISAC) system. We aim to maximize Radar signal-to-interference-plus-noise-ratio (SINR) by jointly optimizing the beamforming matrix at the dual-function Radar-communication (DFRC) base station (BS) and the reflecting coefficient matrix at the active RIS subject to the quality of service (QoS) constraint of communication users (UE) and the transmit power constraints of active RIS and DFRC BS. In the proposed scenario, we mainly focus on the four-hop BS-RIS-target-RIS-BS sensing link, and the direct BS-target-BS link is assumed to be blocked. Due to the coupling of the beamforming matrix and the reflecting coefficient matrix, we use the alternating optimization (AO) method to solve the problem. Given reflecting coefficients, we apply majorization-minimization (MM) and semidefinite programming (SDP) methods to deal with the nonconvex QoS constraints and Radar SINR objective functions. An initialization method is proposed to obtain a high-quality converged solution, and a sufficient condition of the feasibility of the original problem is provided. Since the signal for sensing is reflected twice at the same active RIS panel, the Radar SINR and active RIS transmit power are quartic functions of RIS coefficients after using the MM algorithm. We then transform the problem into a sum of square (SOS) form, and a semidefinite relaxation (SDR)-based algorithm is developed to solve the problem. Finally, simulation results validate the potential of active RIS in enhancing the performance of the ISAC system compared to the passive RIS, and indicate that the transmit power and physical location of the active RIS should be carefully chosen.

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“…Wireless sensing aims to precisely and effectively detect, estimate, and derive valuable physical data or characteristics from specific targets through the utilization of radio wave propagation, reflection, diffraction, and scattering [32]. In [33], the authors discussed integrated sensing and communications with RIS. The authors also discussed future directions and applications for ISAC.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Unit Cells of a Reconfigurable Intelligence Surface Integrated with Sensing Capability at the mmWave Frequency Band

Rana,

Cho,

Hong

2024

Electronics

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Integrated sensing and communication (ISAC) is emerging as a main feature for 5G/6G communications. To enhance spectral and energy efficiencies in wireless environments, reconfigurable intelligent surfaces (RISs) will play a significant role in beyond-5G/6G communications. Multi-functional RISs, capable of not only reflecting or transmitting the beam in desired directions but also sensing the signal, wirelessly transferring power to nearby devices, harvesting energy, etc., will be highly beneficial for beyond-5G/6G applications. In this paper, we propose a nearly 2-bit unit cell of RISs integrated with sensing capabilities in the millimeter wave (mmWave) frequency band. To collect a very small fraction of the impinging signals through vias, we employed substrate integrated waveguide (SIW) technology at the bottom of the unit cell and a via. This enabled the sensing of incoming signals, requiring only a small amount of the impinging signal to be collected through SIW. Initially, we utilized Floquet ports and boundary conditions to obtain various parameters of the unit cells. Subsequently, we examined 1 × 3-unit cells, placing them on the waveguide model to obtain the required parameters of the unit cell. By using the waveguide and 1 × 3-unit cell arrays, the sensing amount was also determined.

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Integrated Sensing and Communication with Reconfigurable Intelligent Surfaces: Opportunities, Applications, and Future Directions

Cited by 54 publications

References 14 publications

Impact of Pilot Contamination Between Operators With Interfering Reconfigurable Intelligent Surfaces

Impact of Pilot Contamination Between Operators With Interfering Reconfigurable Intelligent Surfaces

Active RIS Aided Integrated Sensing and Communication Systems

Characterization of Unit Cells of a Reconfigurable Intelligence Surface Integrated with Sensing Capability at the mmWave Frequency Band

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