Array Rotation in Near-Field ISAC: Communication, Detection, and Estimation Under Low-Complexity Transmit Architectures
Abstract
This paper studies near-field integrated sensing and communication (ISAC) with a rotatable base-station array under an exact spherical-wave propagation model. For a general transmit covariance, we derive a Cramér--Rao bound (CRB) decomposition that separates target-side geometry from transmit-covariance-dependent terms. We then specialize the framework to two representative low-complexity architectures: a single-stream superposition architecture, and a dual-waveform split architecture design. We characterize the communication-, detection-, and estimation-optimal rotations for each architecture using the exact finite-array model. In addition, we show how a second-order approximation yields compact approximate expressions for the optimal rotation angles. We also study uncertainty in the target state used for beamforming design through a correlated Gaussian perturbation model, and derive approximations of the optimal robust rotation angles for target sensing and detection. The analysis shows that the two architectures behave differently under rotation: the single-stream design can align communication and detection tasks, whereas the dual-waveform design exhibits a direct communication--detection tradeoff and can incur a larger communication loss when sensing is prioritized. Numerical results show clear gains over a fixed array orientation, especially for range estimation, and close agreement between the approximate and exact rotation choices. Detection is less affected by target-state errors than estimation in the considered cases.
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BibTeX
@misc{soltani2026array,
title = {{Array Rotation in Near-Field ISAC: Communication, Detection, and Estimation Under Low-Complexity Transmit Architectures}},
author = {Marziyeh Soltani and Mark F. Flanagan},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.31136},
eprint = {2610.31136},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.31136},
}
RIS
TY - UNPB
TI - Array Rotation in Near-Field ISAC: Communication, Detection, and Estimation Under Low-Complexity Transmit Architectures
AU - Marziyeh Soltani
AU - Mark F. Flanagan
PY - 2026
DA - 2026/10/24
PB - arXiv
DO - 10.48550/arxiv.2610.31136
UR - https://arxiv.org/abs/2610.31136
AB - This paper studies near-field integrated sensing and communication (ISAC) with a rotatable base-station array under an exact spherical-wave propagation model. For a general transmit covariance, we derive a Cramér--Rao bound (CRB) decomposition that separates target-side geometry from transmit-covariance-dependent terms. We then specialize the framework to two representative low-complexity architectures: a single-stream superposition architecture, and a dual-waveform split architecture design. We characterize the communication-, detection-, and estimation-optimal rotations for each architecture using the exact finite-array model. In addition, we show how a second-order approximation yields compact approximate expressions for the optimal rotation angles. We also study uncertainty in the target state used for beamforming design through a correlated Gaussian perturbation model, and derive approximations of the optimal robust rotation angles for target sensing and detection. The analysis shows that the two architectures behave differently under rotation: the single-stream design can align communication and detection tasks, whereas the dual-waveform design exhibits a direct communication--detection tradeoff and can incur a larger communication loss when sensing is prioritized. Numerical results show clear gains over a fixed array orientation, especially for range estimation, and close agreement between the approximate and exact rotation choices. Detection is less affected by target-state errors than estimation in the considered cases.
ER -