Joint Discrete Pinching-Antenna Activation and Beamforming Design for Efficient PASS-ISAC

Abstract

Pinching-antenna systems (PASS) offer flexible radiation points for integrated sensing and communication (ISAC), but existing designs largely assume continuous antenna placement, which may be impractical with pre-installed hardware. We investigate a discrete-activation multi-waveguide PASS-ISAC system that selects sparse transmit and receive pinching antennas (TPAs/RPAs) from predefined locations. We formulate a communication-rate maximization problem by jointly optimizing beamforming and TPA/RPA activation under transmit-power, activation, and sensing signal-to-noise ratio (SNR) constraints. To solve this nonconvex problem, we develop a low-complexity joint discrete pinching-antenna activation and beamforming optimization (JDPABO) algorithm based on alternating optimization, successive convex approximation, and reweighted $\ell_1$ minimization. Simulations show that JDPABO approaches continuous-placement performance at low sensing SNR requirements and outperforms fixed activation schemes with sparse PA activation.