Near-Field ISAC: Performance Analysis and Rate Region Characterization

A near-field integrated sensing and communications (ISAC) framework is proposed with an accurate channel model, where the effective aperture loss is considered. Based on the proposed framework, sensing and communication performance are analyzed in terms of three different beamforming designs: a communications-centric design, a sensing-centric design, and a Pareto optimal design. Within each design, the closed-form expressions of sensing rates (SRs) and communication rates (CRs) are derived. Moreover, the attainable SR-CR regions of the near-field ISAC are characterized. Numerical results reveal that the performance of the proposed near-field ISAC framework converges to upper bounds as the number of BS antennas increases.