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arXiv · 2506.15470

Analyzing URA Geometry for Enhanced Spatial Multiplexing and Extended Near-Field Coverage

Ahmed Hussain·Asmaa Abdallah·Abdulkadir Celik·Ahmed M. Eltawil
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Abstract

With the deployment of large antenna arrays at high frequency bands, future wireless communication systems are likely to operate in the radiative near-field. Unlike far-field beam steering, near-field beams can be focused within a spatial region of finite depth, enabling spatial multiplexing in both the angular and range dimensions. This paper derives the beamdepth for a generalized uniform rectangular array (URA) and investigates how array geometry influences the near-field beamdepth and the limits where near-field beamfocusing is achievable. To characterize the near-field boundary in terms of beamfocusing and spatial multiplexing gains, we define the effective beamfocusing Rayleigh distance (EBRD) for a generalized URA. Our analysis reveals that while a square URA achieves the narrowest beamdepth, the EBRD is maximized for a wide or tall URA. However, despite its narrow beamdepth, a square URA may experience a reduction in multiuser sum rate due to its severely constrained EBRD. Simulation results confirm that a wide or tall URA achieves a sum rate of 3.5 X more than that of a square URA, benefiting from the extended EBRD and improved spatial multiplexing capabilities.

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Ahmed Hussain, Asmaa Abdallah, Abdulkadir Celik, Ahmed M. Eltawil. 2025-06-18. Analyzing URA Geometry for Enhanced Spatial Multiplexing and Extended Near-Field Coverage. https://arxiv.org/abs/2506.15470

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