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arXiv · 2511.06383

Performance Bounds for Near-Field Velocity Estimation With Modular Linear Array

Khalid A. Alshumayri·Mudassir Masood·Ali. A. Nasir
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Abstract

Velocity estimation is a cornerstone of the recently introduced near-field predictive beamforming. This paper derives the Cramer-Rao bounds (CRBs) for joint radial and transverse velocity estimation within a predictive beamforming framework employing a modular linear array (MLA). We obtain closed-form expressions that characterize the interplay between array geometry and estimation accuracy, showing that increasing the inter-module separation enlarges the effective aperture and reduces the transverse-velocity CRB, while the radial-velocity CRB remains largely insensitive to this separation. Furthermore, we show that an MLA can achieve the same accuracy as a collocated ULA with fewer antennas and quantify the relation between inter-module spacing and antenna savings. The derived expressions are validated through simulations by comparing them with the mean-squared error (MSE) of the maximum likelihood estimator (MLE) reported in the literature.

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Khalid A. Alshumayri, Mudassir Masood, Ali. A. Nasir. 2025-11-09. Performance Bounds for Near-Field Velocity Estimation With Modular Linear Array. https://arxiv.org/abs/2511.06383

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