Near-Field Sparse MIMO Bistatic OFDM-ISAC for Low-Altitude UAV Swarm

作者：Hongqi Min, Tao Liu, Yong Zeng · 年份：2025 · DOI：10.1109/globecom59602.2025.11432370 · 被引用次数：2 · 研究领域：Radar Systems and Signal Processing、UAV Applications and Optimization、Direction-of-Arrival Estimation Techniques

Integrated sensing and communications (ISAC) is a pivotal technology for low-altitude unmanned aerial vehicle (UAV) swarm. As the sensing targets for UAV swarm systems are usually densely located, the conventional compact multi-input multi-output (MIMO) with half-wavelength antenna spacing usually leads to prohibitive hardware, energy and signal processing costs when large array aperture is needed to achieve fine spatial resolution. By relaxing the traditional half-wavelength spacing constraint, sparse MIMO may achieve a larger array aperture without having to increase the number of antenna elements or radio frequency (RF) chains, which improves spatial resolution for both communication and sensing. Besides, sparse MIMO may also result in a larger near-field region. Therefore, in this paper, we study the near-field sparse MIMO bistatic orthogonal frequency division multiplexing (OFDM)-ISAC for low-altitude UAV swarm systems and propose the framework that utilizes physical array for communication while virtual array for sensing. The proposed method forms virtual arrays at the ISAC transmitter and sensing receiver simultaneously, while eliminating the angle and range coupling effect. As a result, high-resolution angle estimation based on virtual array is achieved. Simulation results demonstrate that sparse MIMO simultaneously improves communication sum rates and sensing resolution compared to the conventional compact MIMO.