Near-Field Beamforming for Large Intelligent Surfaces
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A4 Artikkeli konferenssijulkaisussa
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en
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7
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2022 IEEE 33rd Annual International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2022, pp. 1367-1373, IEEE International Symposium on Personal, Indoor and Mobile Radio Communications ; Volume 2022-September
Abstract
In this paper, we propose a novel near-field beamforming (BF) design with a Large Intelligent Surface (LIS) that is implemented as a discretized 2D-array. We first investigate the definitions of the near-field and far-field regions, and determine the Fraunhofer distance of the LIS, which scales up linearly in the surface-area of the LIS. Hence, a user-equipment (UE) can enter the near-field of a LIS in practice. In addition to Fraunhofer distance, we further derive the Fresnel near-field region where both amplitude and angle variations are negligible, as long as the distance from the UE to the LIS is larger than a threshold, which only scales up linearly in the diameter of LIS. Therefore, in the majority region of near-field, only phase variations worsen the the quality of received signal and result in significant array-gain losses. Motivated by this observation, we further propose a two-step near-field BF design that can effectively recover the array-gain losses in Fresnel near-field, and is fully compatible with a conventional far-field BF.Description
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Hu, S, Ilter, M C & Wang, H 2022, Near-Field Beamforming for Large Intelligent Surfaces. in 2022 IEEE 33rd Annual International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2022. IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, vol. 2022-September, IEEE, pp. 1367-1373, IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, Virtual, Online, Japan, 12/09/2022. https://doi.org/10.1109/PIMRC54779.2022.9977582