通信感知一体化的信息理论极限

Wireless sensing has become an important native capability in next-generation wireless networks (including 6G and Wi-Fi 7) and is widely recognized in the communications industry. Integrated sensing and communications (ISAC) is a promising technology that integrates communication and sensing functionalities into a single wireless system, thereby reducing wireless resource and infrastructure costs and improving communication and sensing subsystem performances. The performance tradeoff between communication and sensing (C&S) is one of the most important fundamental problems of ISAC. This paper argues that performance limits and achievable performance regions are essential techniques for studying C&S tradeoffs. Existing contributions are investigated from four aspects:capacity-distortion theory, C&S performance boundary theory based on mean square error, C&S performance boundary theory based on equivalent sensing rate, and target-detection-oriented C&S performance boundary theory. Moreover, this C&S tradeoff is twofold, comprising the deterministic-random and subspace tradeoffs. As a step further, we discuss the ISAC performance limits based on practical 5G NR frame structures. Finally, representative open problems associated with the information-theoretic limits of ISAC systems are summarized.