Cited by 127Advanced Antenna and Metasurface TechnologiesDirection-of-Arrival Estimation TechniquesAdvanced Wireless Communication Technologies

Two-Dimensional Direction-of-Arrival Estimation Using Stacked Intelligent Metasurfaces

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An, Jiancheng, Yuen, Chau, Guan, Yong Liang, Renzo, Marco Di, Debbah, Mérouane, Poor, H. Vincent, Hanzo, Lajos·2024·IEEE Journal on Selected Areas in Communications

Abstract

Stacked intelligent metasurfaces (SIMs) are capable of emulating reconfigurable physical neural networks by utilizing electromagnetic (EM) waves as carriers. They can also perform various complex computational and signal processing tasks. An SIM is constructed by densely integrating multiple metasurface layers, each consisting of a large number of small meta-atoms that can control the EM waves passing through it. In this paper, we harness an SIM for two-dimensional (2D) direction-of-arrival (DOA) estimation. In contrast to conventional designs, an advanced SIM in front of a receiver array can be designed to automatically compute the 2D discrete Fourier transform (DFT) as the incident waves propagate through it. As a result, a receiver array can directly observe the angular spectrum of the incoming signal, and it can estimate the DOA by simply using probes to detect the energy distribution on the receiver array. This avoids the need for power inefficient radio frequency chains. To enable an SIM to perform the 2D DFT in the wave domain, we formulate an optimization problem that minimizes the mean square error (MSE) between the SIM’s EM response and the 2D DFT matrix. Then, a gradient descent algorithm is customized for iteratively updating the phase shift applied by each meta-atom of the SIM. To further improve the DOA estimation accuracy, we configure the phase shifts of the input layer of the SIM to generate a set of 2D DFT matrices associated with orthogonal spatial frequency bins. Additionally, we analytically evaluate the performance of the proposed SIM-based DOA estimator by deriving a tight upper bound for the MSE. Extensive numerical simulations verify the capability of an optimized SIM to perform DOA estimation and corroborate the theoretical analysis. Specifically, we show that an SIM is capable of performing DOA estimation with an MSE of the order of$10^{-4}$.

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Crossref · 10.1109/jsac.2024.3414613

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  • Recent prototypes have demonstrated SIMs with capabilities for MIMO beamforming, radar sensing, and image classification.

    “Recent prototypes have demonstrated SIMs with impressive capabilities for applications such as MIMO beamforming [25], radar sensing [26], and image classification [27].”

    From Emerging Technologies in Intelligent Metasurfaces: Shaping the Future of Wireless Communications (2026) · cites this paper as [26]

    The paper studies SIM-based direction-of-arrival estimation, which is relevant to radar sensing. Its radar discussion describes probing ground targets as a potential application, while the performance section reports simulations; it does not demonstrate a radar-sensing prototype. The separate MIMO and image-classification citations are not attributed to this source. (LLM, conf=0.87)

    Experimental — accuracy not yet measured
  • By properly configuring the transmission coefficients of the meta-atoms on each metasurface, a SIM can automatically accomplish various advanced computation and signal processing tasks as electromagnetic waves propagate through the layered structure at the speed of light.

    “By properly configuring the transmission coefficients of the meta-atoms on each metasurface, a SIM becomes capable of automatically accomplishing various advanced computation and signal processing tasks as EM waves propagate through the layered structure at the speed of light [25], [26].”
  • The field response impinging on each layer is the weighted sum of the diffracted fields from the meta-atoms on the previous layer, with the weight coefficient determined by the product of the complex-valued transmission coefficients and corresponding propagation coefficients.

    “The field response impinging on each layer is the weighted sum of the diffracted fields from the meta-atoms on the previous layer, with the weight coefficient determined by the product of the complex-valued transmission coefficients and corresponding propagation coefficients [25], [26].”
  • Numerical simulations have confirmed that an optimized SIM can perform DOA estimation with remarkable speed and accuracy, achieving an MSE of -40 dB.

    “Numerical simulations have confirmed that an optimized SIM can perform DOA estimation with remarkable speed and accuracy, achieving an MSE of -40 dB.”

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Research works printed but not linked: 6

  1. J. An, C. Yuen, M. Di Renzo, M. Debbah, H. V. Poor, and L. Hanzo, "Stacked intelligent metasurface performs a 2D DFT in the wave domain for DOA estimation," arXiv preprint arXiv:2310.09861, 2023. · arXiv
  2. J. An, C. Xu, L. Wang, Y. Liu, L. Gan, and L. Hanzo, "Joint training of the superimposed direct and reflected links in reconfigurable intelligent surface assisted multiuser communications," IEEE Trans. Green Commun. Netw., vol. 6, no. 2, pp. 739-754, Jun. 2022.
  3. C. Xu et al., "Channel estimation for reconfigurable intelligent surface assisted high-mobility wireless systems," IEEE Trans. Veh. Technol., vol. 72, no. 1, pp. 718-734, Jan. 2023.
  4. W. Xu et al., "Algorithm-unrolling-based distributed optimization for ris-assisted cell-free networks," IEEE Int. Things J., vol. 11, no. 1, pp. 944-957, Jan. 2024.
  5. C. Xu et al., "Antenna selection for reconfigurable intelligent surfaces: A transceiver-agnostic passive beamforming configuration," IEEE Trans. Wireless Commun., vol. 22, no. 11, pp. 7756-7774, Nov. 2023.
  6. Q.-U.-A. Nadeem et al., "Hybrid digital-wave domain channel estimator for stacked intelligent metasurface enabled multi- user miso systems," arXiv preprint arXiv:2309.16204, 2023. · arXiv

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Authors
An, J., Yuen, C., Guan, Y. L., Renzo, M. D., Debbah, M., Poor, H. V., & Hanzo, L.
Affiliations
  • Nanyang Technological University (SG)
  • Centre National de la Recherche Scientifique (FR)
  • Center for 6G Technology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
  • Princeton University (US)
  • University of Southampton (GB)
Venue
IEEE Journal on Selected Areas in Communications
Published
2024-10
Volume
42
Issue
10
Pages
2786-2802
ISSN
  • 0733-8716 (ISSN-L)
  • 1558-0008
OpenAlex
W4399666068
Cited by
125
References
39
Citations by year
2026: 37 · 2025: 65 · 2024: 23
FWCI
21.57
Type
journal article
Language
en
Open access
Locations
  • IEEE Journal on Selected Areas in Communications (publishedVersion)
  • arXiv (Cornell University) (submittedVersion)
  • HAL (submittedVersion, other-oa)
  • ePrints Soton (University of Southampton) (submittedVersion)
  • DR-NTU (Nanyang Technological University) (submittedVersion)
  • arXiv (Cornell University)
Funders
  • Ministry of Education, Singapore, under its MOE Tier 2 (MOE-T2EP50220-0019)
  • National Research Foundation Singapore
  • Infocomm Media Development Authority under its Future Communications Research and Development Program
  • European Commission through the Horizon Europe projects titled COVER (101086228)
  • Università degli Studi di Teramo (101129618)
  • INSTINCT (101139161)
  • Agence Nationale de la Recherche (ANR) through the France 2030 Project titled ANR-PEPR Networks of the Future (NF-YACARI 22-PEFT-0005)
  • CHIST-ERA Project titled PASSIONATE (CHIST-ERA-22-WAI-04, ANR-23-CHR4-0003-01)
  • National Science Foundation (CNS-2128448)
  • Engineering and Physical Sciences Research Council (EP/W016605/1, EP/X01228X/1, EP/Y026721/1, EP/W032635/1)
  • European Research Council’s Advanced Fellow Grant QuantCom (789028)
Topics
  • Physical Sciences › Engineering › Aerospace Engineering › Advanced Antenna and Metasurface Technologies
  • Physical Sciences › Computer Science › Signal Processing › Direction-of-Arrival Estimation Techniques
  • Physical Sciences › Engineering › Electrical and Electronic Engineering › Advanced Wireless Communication Technologies
Keywords
stacked intelligent metasurfaces, direction of arrival estimation, two-dimensional DOA estimation, two-dimensional discrete Fourier transform, receiver array, angular spectrum, reconfigurable neural networks, meta-atoms

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