飞行员何时对OFDM感知重要？面向ISAC的导频-数据资源设计

中文摘要 AI 辅助

基于OFDM的集成感知与通信（ISAC）实际信号包含确定性导频和随机数据载荷，然而这两类资源如何共同影响匹配滤波感知性能仍未得到充分理解。本文建立了导频-数据（P-D）OFDM感知的分析与优化框架。我们首先推导了闭式均方周期自相关函数（MS P-ACF），该函数刻画了平均子载波功率谱和数据符号随机性对感知旁瓣的各自贡献。基于此结果，我们揭示：在均匀功率分配下，导频放置对归一化旁瓣无影响，对归一化全局期望积分旁瓣电平（EISL）也无影响；而在非均匀功率分配下，导频放置成为重塑旁瓣的有效设计自由度。我们进一步推导了全局EISL最小化的全局最优两级导频-数据功率分配，并刻画了用于峰值旁瓣抑制的导频放置。针对感兴趣区域（ROI）感知，我们联合优化导频放置和子载波功率分配以最小化归一化ROI-EISL。在特定条件下，严格均匀导频放置被证明是全局最优的，同时针对一般资源配置开发了二分-分支定界算法。数值结果验证了理论分析，并表明与优化均匀导频OFDM相比，所提设计将ROI旁瓣电平降低最多2.19 dB，同时在信噪比为-10 dB时将测距精度提高84.3%。这些结果揭示了何时以及如何利用导频放置来调控随机OFDM通信信号的感知行为，为基于OFDM的ISAC提供了实用的资源设计原则。

英文摘要

Practical OFDM-based integrated sensing and communication (ISAC) signals contain deterministic pilots and random data payloads, yet how these two types of resources jointly affect matched-filter sensing performance remains insufficiently understood. This paper establishes an analytical and optimization framework for pilot-data (P-D) OFDM sensing. We first derive a closed-form mean-square periodic autocorrelation function (MS P-ACF), which characterizes the respective contributions of the average subcarrier power spectrum and data-symbol randomness to sensing sidelobes. Based on this result, we reveal that pilot placement has no impact on normalized sidelobes under uniform power allocation or on the normalized global expected integrated sidelobe level (EISL), whereas it becomes an effective design degree of freedom for reshaping sidelobes under nonuniform power allocation. We further derive the globally optimal two-level pilot-data power allocation for global EISL minimization and characterize pilot placement for peak sidelobe suppression. For region-of-interest (ROI) sensing, we jointly optimize pilot placement and subcarrier power allocation to minimize the normalized ROI-EISL. A strictly uniform pilot placement is proved globally optimal under specified conditions, while a bisection-and-branch-and-bound algorithm is developed for general resource configurations. Numerical results validate the theoretical analysis and demonstrate that the proposed design reduces the ROI sidelobe level by up to 2.19 dB compared with optimized uniform-pilot OFDM, while improving ranging accuracy at an SNR of -10 dB by 84.3$\%$. These results reveal when and how pilot placement can be exploited to regulate the sensing behavior of random OFDM communication signals, providing practical resource-design principles for OFDM-based ISAC.

发表机构

• State Key Laboratory of Novel Software Technology, Nanjing University（南京大学软件新技术国家重点实验室）
• School of Intelligent Software and Engineering, Nanjing University (Suzhou Campus)（南京大学智能软件与工程学院（苏州校区））
• Yangtze Delta Region Institute (Quzhou), University of Electronic Science and Technology of China（电子科技大学长三角研究院（衢州））

机构由 AI 辅助整理，请以论文原文为准。