Coordinated Multi-Point Enabled ISAC Under Asynchronous Errors: Performance Analysis and Waveform-Beamforming Optimization

Abstract

The coordinated multi-point approach presents promising opportunities for integrated sensing and communication, offering enhanced coverage and accuracy. However, inevitable timing inconsistencies across participating transceivers lead to signal asynchrony, diminishing the effectiveness of this paradigm. This paper presents a novel coordinated sensing and communication scheme designed to mitigate asynchronous challenges. Specifically, asynchronous errors are jointly estimated alongside target locations, then enabling synchronization corrections for improved coordinated communication. To quantify performance bounds, closed-form expressions of the Cramer-Rao bound and asymptotic communication capacity under given asynchronous levels are derived. On this basis, a two-stage optimization framework is developed to explicitly optimize the coordinated sensing waveform and communication beamforming, further enhancing the resistance to asynchrony. The framework leverages the Schur complement-based semi-definite relaxation to address the non-linear and non-convex challenges in the sensing design. For the communication stage, a conjugate gradient method with penalty terms is proposed to address the high complexity of the multi-variable non-convex problem. These efforts enhance coordinated sensing and communication in asynchronous scenarios, with simulation results provided to verify their effectiveness.