Fundamental Limits of Integrated Sensing and Communication Over Interference Channels

This paper focuses on integrated sensing and communication (ISAC) over interference channels. An information-theoretic modeling, where two interfering ISAC base stations (BSs) seek to communicate with their users while performing sensing estimation through received echo signals, is proposed. For the model considered, we establish both inner and outer bounds for the capacity-distortion region, with capacity and sensing distortion as the key performance metrics for communication and sensing, respectively. As for the inner bound, an achievable scheme utilizing superposition coding and joint compression of past transmitted codewords and echo signals is developed, and the corresponding achievable rate-distortion region is derived. The proposed outer bound is based on the ideas of cut-set bound on communication rate and rate-limited constraints on sensing distortion. Several numerical examples are constructed to illustrate the advantages of our proposed scheme. Our results highlight that interference links, in conjunction with echo signals, can be strategically leveraged to achieve unified cooperative sensing and communication between the two BS-user pairs.