AI 中文总结
针对双基地ISAC中数据载荷不确定性导致的旁瓣退化，推导RF和MF的PSLR闭式表达式，并提出DPU感知的MMSE接收机，仿真验证其检测性能优于RF和MF。
AI 中文摘要
我们研究了双基地集成感知与通信（ISAC）系统中数据载荷不确定性（DPU）的问题，该问题指感知接收端对发射数据符号的不完全了解。DPU可能源于基站（BS）到BS双基地感知中前传容量有限，或BS到用户设备（UE）双基地感知中的数据解调错误，并可通过延迟-多普勒域中升高的旁瓣电平损害目标检测。为表征此效应，我们推导了在DPU下两种常见OFDM接收机，即互易滤波（RF）和匹配滤波（MF），的峰值旁瓣电平比（PSLR）的闭式表达式。分析表明，RF的DPU引起的旁瓣退化取决于逆二阶、四阶和六阶星座矩，而MF的退化仅取决于直接四阶矩，使得RF对DPU明显更脆弱。为缓解由此产生的旁瓣，我们进一步提出了一种新颖的、感知DPU的最小均方误差（MMSE）接收机。仿真结果验证了PSLR分析，并展示了MMSE相对于RF和MF的优越检测性能，同时揭示了相对于具有完美数据载荷知识的genie辅助接收机，MMSE能在多大程度上恢复DPU引起的性能损失。
英文摘要
We investigate the problem of data payload uncertainty (DPU) in bistatic integrated sensing and communication (ISAC) systems, which refers to imperfect knowledge of transmit data symbols at the sensing receiver. DPU may result from limited fronthaul capacity in base station (BS)-to-BS bistatic sensing or data demodulation errors in BS-to-user equipment (UE) bistatic sensing, and can impair target detection through elevated sidelobe levels in the delay-Doppler domain. To characterize this effect, we derive closed-form expressions for the peak-to-sidelobe level ratio (PSLR) of two common OFDM receivers, namely reciprocal filtering (RF) and matched filtering (MF), under DPU. The analysis shows that the DPU-induced sidelobe degradation of RF depends on the inverse second-, fourth-, and sixth-order constellation moments, whereas that of MF depends only on the direct fourth-order moment, making RF considerably more vulnerable to DPU. To mitigate the resulting sidelobes, we further propose a novel, DPU-aware minimum mean-squared-error (MMSE) receiver. Simulation results validate the PSLR analysis and demonstrate superior detection performance of MMSE over RF and MF while revealing the extent to which it can recover DPU-induced performance loss relative to a genie-aided receiver with perfect knowledge of data payload.
