基于导频的双基地集成感知与通信采样频偏估计
Pilot-Based SFO Estimation for Bistatic Integrated Sensing and Communication
AI总结：
本文针对双基地ISAC中采样频偏估计精度不足的问题，提出基于导频的TITO算法，利用参考路径时延偏移自适应估计SFO，并通过RIS构建非视距场景下的参考路径，仿真与实测验证了其优越性。
摘要：
在面向未来第六代移动网络的双基地雷达感知与集成感知与通信（ISAC）融合背景下，实现严格的同步精度至关重要，而通过空中同步达成这一目标尤其困难。现有算法能够较好地处理时间偏移和频率偏移，但对采样频偏（SFO）的估计精度不足，导致所获得的雷达图像质量下降，表现为信噪比损失以及距离和多普勒频移的偏移。本文提出一种名为时间偏移倾斜推断（TITO）的SFO估计算法，适用于基于正交频分复用（OFDM）的ISAC系统。TITO利用可用的导频子载波获取信道冲激响应估计，并提取由SFO引起的时延偏移信息，该时延偏移作用于发射与接收ISAC节点之间具有恒定距离、多普勒频移和角度的主导参考路径。随后，TITO自适应地选择仅受SFO引起的符号间干扰影响可忽略不计的时延估计值，最终利用这些估计值来估计SFO。针对上述发射与接收ISAC节点之间不存在直接视距（LoS）的场景，本文提出了一种利用中继可重构智能表面（RIS）来构建上述参考路径的系统方案。除了对精度界限进行数学推导外，本文还给出了在26.2 GHz频率下的仿真与实测结果，以证明TITO在SFO估计精度和鲁棒性方面优于现有方法。
英文摘要：
Enabling bistatic radar sensing within the context of integrated sensing and communication (ISAC) for future sixth generation mobile networks demands strict synchronization accuracy, which is particularly challenging to be achieved with over-the-air synchronization. Existing algorithms handle time and frequency offsets adequately, but provide insufficiently accurate sampling frequency offset (SFO) estimates that result in degradation of obtained radar images in the form of signal-to-noise ratio loss and migration of range and Doppler shift. This article introduces an SFO estimation algorithm named tilt inference of time offset (TITO) for orthogonal frequency-division multiplexing (OFDM)-based ISAC. Using available pilot subcarriers, TITO obtains channel impulse response estimates and extracts information on the SFO-induced delay migration to a dominant reference path with constant range, Doppler shift, and angle between transmit and receive ISAC nodes. TITO then adaptively selects the delay estimates that are only negligibly impaired by SFO-induced intersymbol interference, ultimately employing them to estimate the SFO. Assuming a scenario without a direct line-of-sight (LoS) between the aforementioned transmitting and receiving ISAC nodes, a system concept with a relay reflective intelligent surface (RIS) is used to create the aforementioned reference path is proposed. Besides a mathematical derivation of accuracy bounds, simulation and measurements at 26.2 GHz are presented to demonstrate TITO's superiority over existing methods in terms of SFO estimation accuracy and robustness.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
