发表机构
Istanbul Medipol University（伊斯坦布尔医科大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出FM-OFDM作为恒包络感知波形，分析其优于CP-OFDM的感知特性，并开发低复杂度加权相位增量多普勒估计器，实现约20 dB动态范围增益。
AI 中文摘要
循环前缀正交频分复用（CP-OFDM）被广泛用作集成感知与通信（ISAC）的参考波形。然而，其高峰均功率比（PAPR）需要功率放大器回退，从而减少了可用的感知链路预算。调频OFDM（FM-OFDM）提供了一种具有0 dB PAPR的恒包络信号，并已在高移动性场景中展现出可靠的通信性能，但其感知特性在很大程度上仍未得到探索。本文基于带宽、模糊函数、旁瓣行为和多普勒估计能力，将FM-OFDM表征为一种感知波形。分析表明，其数据依赖的旁瓣基底是不相干的，并通过跨帧积分而降低，而相应的CP-OFDM基底保持不变。因此，在相等的占用带宽和发射功率下，帧级积分逆转了单符号性能排序，并为FM-OFDM提供了约20 dB的额外动态范围，用于弱目标检测。此外，FM-OFDM模糊函数的零延迟切片被证明是确定性的，且独立于传输的数据实现，这与线性调制波形形成对比，同时推导了远离零延迟切片的旁瓣基底的闭式表达式。由于数据符号与时域样本之间的非线性映射阻止了传统CP-OFDM距离-多普勒处理链的直接应用，因此开发了一种加权相位增量多普勒估计器。所提出的估计器能够以最小计算复杂度对感知基底及其交叉点进行闭式预测。
英文摘要
Cyclic-prefix orthogonal frequency-division multiplexing (CP-OFDM) is widely adopted as a reference waveform for integrated sensing and communication (ISAC). However, its high peak-to-average power ratio (PAPR) requires power amplifier back-off, thereby reducing the available sensing link budget. Frequency-modulated OFDM (FM-OFDM) provides a constant-envelope signal with 0 dB PAPR and has demonstrated reliable communication performance in high-mobility scenarios, but its sensing characteristics remain largely unexplored. This paper characterizes FM-OFDM as a sensing waveform based on its bandwidth, ambiguity function, sidelobe behavior, and Doppler estimation capability. The analysis shows that its data dependent sidelobe floor is incoherent and decreases through across frame integration, whereas the corresponding CP-OFDM floor remains unchanged. Consequently, under equal occupied bandwidth and transmit power, frame-level integration reverses the single-symbol performance ordering and provides FM-OFDM with approximately 20 dB of additional dynamic range for weak-target detection. Moreover, the zero-delay cut of the FMOFDM ambiguity function is shown to be deterministic and independent of the transmitted data realization, in contrast to linearly modulated waveforms, while a closed-form expression is derived for the sidelobe floor away from the zero-delay cut. Since the nonlinear mapping between the data symbols and time-domain samples prevents the direct application of the conventional CP-OFDM range-Doppler processing chain, a weighted phase-increment Doppler estimator is developed. The proposed estimator enables closed-form prediction of the sensing floor and its crossover point with a minimum computational complexity.
