AI 中文总结
研究 OFDM-ISAC 中 IQ 不平衡问题，提出直接利用 IQI 受损观测结构的方法，通过椭圆原子组表示和椭圆组正交匹配追踪检测器，经两次加权二维 FFT 及局部组投影计算相关性，提升了精确支持恢复和弱目标检测性能。
AI 中文摘要
接收机同相/正交不平衡（IQI）会将每个 OFDM 子载波与其镜像对应子载波耦合，在正交频分复用（OFDM）集成感知与通信（ISAC）中产生虚假目标并降低距离-多普勒恢复性能。本文不先补偿 IQI 再进行传统处理，而是直接利用 IQI 受损观测的结构。表明每个物理目标会诱导通过目标系数及其共轭相连的耦合直接和镜像分量，这促使为每个候选延迟-多普勒单元采用椭圆原子组表示。基于此模型，提出椭圆组正交匹配追踪检测器，通过两次加权二维快速傅里叶变换（FFT）及局部组投影高效计算所需相关性。数值结果表明，该方法相比相应基准在精确支持恢复和弱目标检测方面有改进，尤其在中等和强接收机 IQI 情况下。
英文摘要
Receiver in-phase/quadrature imbalance (IQI) couples each OFDM subcarrier with its mirror counterpart, creating ghost targets and degrading range-Doppler recovery in orthogonal frequency division multiplexing (OFDM) integrated sensing and communication (ISAC). Instead of first compensating for IQI and then applying conventional processing, this letter exploits the structure of the IQI-impaired observation directly. We show that each physical target induces coupled direct and mirror components linked through the target coefficient and its conjugate, which motivates an elliptic atom group representation for each candidate delay-Doppler cell. Based on this model, we propose an elliptic group orthogonal matching pursuit detector that performs sparse recovery directly on the received OFDM grid. The required correlations are computed efficiently through two weighted two-dimensional fast Fourier transforms (FFTs) followed by local group projections. Numerical results show that the proposed method improves exact support recovery and weak-target detection compared to corresponding benchmarks, especially under moderate and strong receiver IQI.
CommentsSubmitted to IEEE Wireless Communications Letters
