In this paper, we investigate integrated sensing and communication (ISAC) in high-mobility systems with the aid of an intelligent reflecting surface (IRS). To exploit the benefits of Delay-Doppler (DD) spread caused by high mobility, orthogonal time frequency space (OTFS)-based frame structure and transmission framework are proposed. {In such a framework,} we first design a low-complexity ratio-based sensing algorithm for estimating the velocity of mobile user. Then, we analyze the performance of sensing and communication in terms of achievable mean square error (MSE) and achievable rate, respectively, and reveal the impact of key parameters. Next, with the derived performance expressions, we jointly optimize the phase shift matrix of IRS and the receive combining vector at the base station (BS) to improve the overall performance of integrated sensing and communication. Finally, extensive simulation results confirm the effectiveness of the proposed algorithms in high-mobility systems.

翻译：本文研究了在智能反射面辅助下的高移动性系统中的集成感知与通信。为了利用高移动性引起的时延-多普勒扩展带来的优势，提出了基于正交时频空间的帧结构与传输框架。在此框架下，我们首先设计了一种基于比值的低复杂度感知算法，用于估计移动用户的速度。随后，我们分别从可达均方误差和可达速率的角度分析了感知与通信的性能，并揭示了关键参数的影响。接着，基于推导出的性能表达式，我们联合优化了智能反射面的相移矩阵与基站的接收合并向量，以提升集成感知与通信的整体性能。最后，大量的仿真结果验证了所提算法在高移动性系统中的有效性。