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arXiv · 2508.16218

Hybrid Precoding Revisited: Low-Dimensional Subspace Perspective for MU-MIMO Systems

Mintaek Oh·Jinseok Choi
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Abstract

This letter presents a low-complexity hybrid precoding framework for multiuser multiple-input multiple-output (MIMO) systems by leveraging a low-dimensional subspace property. Under the low-dimensional subspace perspective, we first identify an unconstrained optimal radio-frequency (RF) precoder. We then optimize a hybrid precoder via a reduced-complexity precoding method. We further extend the proposed framework to (i) a dynamic-subarray antenna partitioning algorithm that adaptively allocates subsets of antennas associated with RF chains, and (ii) a channel covariance-based approach to exploit statistical channel state information at a transmitter (CSIT), ensuring robustness with partial CSIT. Simulations validate that our proposed algorithms achieve superior performance while significantly reducing complexity compared to existing methods.

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Mintaek Oh, Jinseok Choi. 2025-08-22. Hybrid Precoding Revisited: Low-Dimensional Subspace Perspective for MU-MIMO Systems. https://arxiv.org/abs/2508.16218

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