Integrated sensing and communication (ISAC) has attracted growing interests for sixth-generation (6G) and beyond wireless networks. The primary challenges faced by highly efficient ISAC include limited sensing and communication (S&C) coverage, constrained integration gain between S&C under weak channel correlations, and unknown performance boundary. Intelligent reflecting/refracting surfaces (IRSs) can effectively expand S&C coverage and control the degree of freedom of channels between the transmitters and receivers, thereby realizing increasing integration gains. In this work, we first delve into the fundamental characteristics of IRS-empowered ISAC and innovative IRS-assisted sensing architectures. Then, we discuss various objectives for IRS channel control and deployment optimization in ISAC systems. Furthermore, the interplay between S&C in different deployment strategies is investigated and some promising directions for IRS enhanced ISAC are outlined.

翻译：一体化感知与通信（ISAC）正引起第六代（6G）及未来无线网络的广泛关注。高效ISAC面临的主要挑战包括受限的感知与通信（S&C）覆盖范围、弱信道相关性下S&C之间受限的集成增益以及未知的性能边界。智能反射/折射面（IRS）能够有效扩展S&C覆盖范围并控制收发器间信道的自由度，从而实现更高的集成增益。本文首先深入探讨IRS赋能ISAC的基本特性以及创新的IRS辅助感知架构。随后，我们讨论了ISAC系统中IRS信道控制与部署优化的多种目标。此外，还研究了不同部署策略下S&C之间的相互作用，并概述了IRS增强型ISAC的一些有前景的研究方向。