AI 中文总结
研究双基地 OFDM 测距系统在失配滤波下的性能，推导 BPSK 等星座的期望旁瓣电平和平均主瓣电平闭式表达式，定量表征信噪比驱动的符号决策误差对延迟域旁瓣行为的影响，仿真验证理论推导。
AI 中文摘要
本文研究了采用正交频分复用（OFDM）的双基地综合感知与通信（ISAC）系统的测距性能。在该系统中，ISAC 发射机发射携带随机数据符号的通信波形，单独的接收机通过将接收信号与本地解调符号序列相关来进行测距。由于不可避免的解调误差，测距处理器在失配滤波而非理想匹配滤波下运行，导致延迟域相关响应的旁瓣结构明确依赖于信噪比（SNR）。针对频率平坦衰落信道，我们推导了 BPSK、QPSK 和一般方形 QAM 星座的所得失配测距响应的期望旁瓣电平（ESL）和平均主瓣电平的闭式表达式。该分析定量表征了 SNR 驱动的符号决策误差如何重塑延迟域旁瓣行为，从而为基于双基地 OFDM 的 ISAC 系统中测距性能的 SNR 相关缩放行为提供分析见解。仿真结果验证了理论推导并证实了所提分析的准确性。
英文摘要
This paper investigates the ranging performance of a bistatic integrated sensing and communications (ISAC) system employing orthogonal frequency-division multiplexing (OFDM), in which an ISAC transmitter emits a communication waveform carrying random data symbols, and a separate receiver performs ranging by correlating the received signal with a locally demodulated symbol sequence. Owing to inevitable demodulation errors, the ranging processor operates under mismatched filtering rather than ideal matched filtering, resulting in a delay-domain correlation response whose sidelobe structure explicitly depends on the signal-to-noise ratio (SNR). Focusing on frequency-flat fading channels, we derive closed-form expressions for the expected sidelobe level (ESL) and the average mainlobe level of the resulting mismatched ranging response for BPSK, QPSK, and general square QAM constellations. The analysis quantitatively characterizes how SNR-driven symbol decision errors reshape the delay-domain sidelobe behavior, thereby providing analytical insight into the SNR-dependent scaling behavior of ranging performance in bistatic OFDM-based ISAC systems. Simulation results validate the theoretical derivations and confirm the accuracy of the proposed analysis.
Comments5 pages, 2 figures, has been accepted by SPAWC 2026
