Holographic Intelligence Surface Assisted Integrated Sensing and Communication

Traditional discrete-array-based systems fail to fully exploit interactions between closely spaced antennas, resulting in inadequate utilization of the aperture resource. In this paper, we propose a holographic intelligence surface (HIS) assisted integrated sensing and communication (HISAC) system, wherein both the transmitter and receiver are fabricated using a continuous-aperture array. To enable tractable design and optimization, we introduce a Fourier-based continuous-discrete transformation, converting the continuous pattern design into a finite-dimensional representation in the wavenumber domain. Based on this transformation, we formulate a joint transmit-receive beamforming optimization problem that aims to maximize multi-target sensing performance while satisfying multi-user communication requirements. To solve the non-convex problem with coupled variables, an alternating optimization algorithm is proposed for HISAC transmit-receive beamforming. Specifically, the transmit beamforming design is solved by decoupling into a series of feasibility-checking sub-problems while the receive beamforming is determined by the Rayleigh quotient-based method. Simulation results demonstrate the superiority of the proposed HISAC system over traditional discrete-array-based ISAC systems, achieving significantly higher sensing performance while guaranteeing predetermined communication performance.