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arXiv · 2602.16459

Continuous Fluid Antenna Sampling for Channel Estimation in Cell-Free Massive MIMO

Masoud Kaveh·Farshad Rostami Ghadi·Francisco Hernando-Gallego·Diego Martin·Riku Jantti·Kai-Kit Wong
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Abstract

In this letter, we develop a continuous fluid antenna (FA) framework for uplink channel estimation in cell-free massive multiple-input and multiple-output (CF-mMIMO) systems. By modeling the wireless channel as a spatially correlated Gaussian random field, channel estimation is formulated as a Gaussian process (GP) regression problem with motion-constrained spatial sampling. Closed-form expressions for the linear minimum mean squared error (LMMSE) estimator and the corresponding estimation error are derived. A fundamental comparison with discrete port-based architectures is established under identical position constraints, showing that continuous FA sampling achieves equal or lower estimation error for any finite pilot budget, with strict improvement for non-degenerate spatial correlation models. Numerical results validate the analysis and show the performance gains of continuous FA sampling over discrete baselines.

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Masoud Kaveh, Farshad Rostami Ghadi, Francisco Hernando-Gallego, Diego Martin, Riku Jantti, Kai-Kit Wong. 2026-02-18. Continuous Fluid Antenna Sampling for Channel Estimation in Cell-Free Massive MIMO. https://arxiv.org/abs/2602.16459

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