Near-field Localization with a Reconfigurable Intelligent Surface Acting as Lens

Abu‐Shaban, Zohair; Keykhosravi, Kamran; Keskin, Musa Furkan; Alexandropoulos, George C.; Seco‐Granados, Gonzalo; Wymeersch, Henk

doi:10.1109/icc42927.2021.9500663

Cited by 104 publications

(99 citation statements)

References 25 publications

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“…For the receiver mode, an RIS can be configured with a nearly continuous phase profile, acting as a lens. Due to the large size of the RIS, wavefront curvature can be harnessed to localize MS and help with system synchronization [14]. For the transmitter mode, an RIS can act similarly to analog transmit beamformer and generate phase-shift keying (PSK) modulated symbols as pilots, hence the channel and position estimation can be performed.…”

Section: B Ris For Localizationmentioning

confidence: 99%

Beyond 5G RIS mmWave Systems: Where Communication and Localization Meet

He¹,

Fan²,

Keykhosravi³

et al. 2021

Preprint

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Upcoming beyond fifth generation (5G) communications systems aim at further enhancing key performance indicators and fully supporting brand new use cases by embracing emerging techniques, e.g., reconfigurable intelligent surface (RIS), integrated communication, localization, and sensing, and mmWave/THz communications. The wireless intelligence empowered by state-of-the-art artificial intelligence techniques has been widely considered at the transceivers, and now the paradigm is deemed to be shifted to the smart control of radio propagation environment by virtue of RISs. In this article, we argue that to harness the full potential of RISs, localization and communication must be tightly coupled. This is in sharp contrast to 5G and earlier generations, where localization was a minor additional service. To support this, we first introduce the fundamentals of RIS mmWave channel modeling, followed by RIS channel state information acquisition and link establishment. Then, we deal with the connection between localization and communications, from a separate and joint perspective.

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Section: B Ris For Localizationmentioning

confidence: 99%

Beyond 5G RIS mmWave Systems: Where Communication and Localization Meet

He¹,

Fan²,

Keykhosravi³

et al. 2021

Preprint

Self Cite

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“…The wireless environment is assumed to also include passive objects contributing to multipath signal reflection. [8], at the UE side [12], or as a separate reflector [13], [14]), wireless settings (multiple-input multiple-output (MIMO) [14], [15], multiple-input single-output (MISO) [10], and singleinput single-output (SISO) [9], [11]), etc. Furthermore, RISs can be used to assist the radar systems to improve the target detection capabilities [16], [17].…”

Section: Introductionmentioning

confidence: 99%

“…For the same scenario, the effects of limited RIS phase resolution was investigated in [18]. In [8], localization with an RIS acting as a lens has been considered and an estimation algorithm was proposed. Nearfield localization with one BS and an RIS has been studied in [6], [9], where it is shown that the wavefront curvature can be used to localize the UE, even if the direct path from the BS to UE is blocked.…”

Section: Introductionmentioning

confidence: 99%

RIS-Enabled Self-Localization: Leveraging Controllable Reflections With Zero Access Points

Keykhosravi¹,

Seco‐Granados²,

Alexandropoulos³

et al. 2022

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Reconfigurable intelligent surfaces (RISs) are one of the most promising technological enablers of the next (6th) generation of wireless systems. In this paper, we introduce a novel use-case of the RIS technology in radio localization, which is enabling the user to estimate its own position via transmitting orthogonal frequency-division multiplexing (OFDM) pilots and processing the signal reflected from the RIS. We demonstrate that user localization in this scenario is possible by deriving Cramér-Rao lower bounds on the positioning error and devising a lowcomplexity position estimation algorithm. We consider random and directional RIS phase profiles and apply a specific temporal coding to them, such that the reflected signal from the RIS can be separated from the uncontrolled multipath. Finally, we assess the performance of our position estimator for an example system, and show that the proposed algorithm can attain the derived bound at high signal-to-noise ratio values.

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“…They can support a wide variety of electromagnetic functionalities [8], ranging from perfect and controllable absorption, beam and wavefront shaping to polarization control, broadband pulse delay, radio-coverage extension, and harmonic generation. The RIS technology is envisioned to coat objects in the wireless environment [2] (e.g., building facades and room walls), and can operate either as a reconfigurable beyond Snell's law reflector [1], or as an analog receiver [9] or lens [10] when equipped with a single Radio-Frequency (RF) chain, or as a transceiver with multiple relevant RF chains [11].…”

Section: Introductionmentioning

confidence: 99%

Non-Coherent Modulation for RIS-Empowered Multi-Antenna OFDM Communications

Chen-Hu,

Alexandropoulos,

Armada

2021

Preprint

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The Reconfigurable Intelligent Surface (RIS) constitutes one of the prominent technologies for the next 6-th Generation (6G) of wireless communications. It is envisioned to enhance signal coverage in cases where obstacles block the direct communication from Base Stations (BSs), and when high carrier frequencies are used that are sensitive to attenuation losses. In the literature, the exploitation of RISs is exclusively based on traditional coherent demodulation, which necessitates the availability of Channel State Information (CSI). Given the CSI, a multi-antenna BS or a dedicated controller computes the pre/post spatial coders and the RIS configuration. The latter tasks require significant amount of time and resources, which may not be affordable when the channel is time-varying or the CSI is not accurate enough. In this paper, we consider the uplink between a single-antenna user and a multi-antenna BS and present a novel RIS-empowered Orthogonal Frequency Division Multiplexing (OFDM) communication system based on the differential phase shift keying, which is suitable for high noise and/or mobility scenarios. Considering both an idealistic and a realistic channel model, analytical expressions for the Signal-to-Interference and Noise Ratio (SINR) and the Symbol Error Probability (SEP) of the proposed non-coherent RIS-empowered system are presented. Our extensive computer simulation results verify the accuracy of the presented analysis and showcase the proposed system's performance and superiority over coherent demodulation in different mobility and spatial correlation scenarios.

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Near-field Localization with a Reconfigurable Intelligent Surface Acting as Lens

Cited by 104 publications

References 25 publications

Beyond 5G RIS mmWave Systems: Where Communication and Localization Meet

Beyond 5G RIS mmWave Systems: Where Communication and Localization Meet

RIS-Enabled Self-Localization: Leveraging Controllable Reflections With Zero Access Points

Non-Coherent Modulation for RIS-Empowered Multi-Antenna OFDM Communications

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