Joint Target Localization and Data Detection in Bistatic ISAC Networks

Existing integrated sensing and communication technology designed for monostatic settings segregates sensing and communication (S&C) at distinct terminals, impeding their adaptability to network paradigms. In this paper, we propose a general framework for joint target-localization and data-detection (JTD) in bistatic settings by using a combination of the deterministic known (DK) and random unknown (RU) symbols, e.g., pilot and data symbols. We first derive the performance limits for target localization-related parameters with combined symbols. We demonstrate that the Fisher information matrix (FIM) for target localization using the DK part can be expressed in a closed form through orthogonal projection, while that using the RU part aligns with the modified FIM in monostatic settings at an exponential rate with respect to the signal-to-noise ratio. Then, we propose a JTD scheme to exploit the reciprocal advantages for S&C, i.e., the detected data symbols are harnessed to enhance target localization in an alternating way. Finally, simulation results validate our theoretical analysis and the effectiveness of the proposed JTD scheme.