Pinching Antenna and Movable Signal Enabled Wireless Communication

Pinching-antenna systems (PASS) reshape wireless channels by moving pinching elements along dielectric waveguides. Movable signals (MS) and rate-splitting multiple access (RSMA) add frequency-domain flexibility and robust interference management, but these three dimensions are often studied in isolation. This paper proposes a unified PASS–MS–RSMA framework for downlink max–min fairness (MMF). We first develop a channel model that captures in-waveguide attenuation and phase via an effective refractive index, together with free-space path loss and phase, and extend it to MS by small carrier-frequency offsets. On this basis, we formulate a joint MMF problem over pinching-antenna positions, carrier frequency, and RSMA power and common-rate allocation. To solve the resulting nonconvex problem, we design two optimization algorithms. The first scheme is a baseline alternating optimization (AO) scheme that combines bisection on the MMF level with a proximal successive convex approximation (P-SCA) for the RSMA variables and a proximal gradient step for the PASS–MS geometry and frequency. The second method uses an explicit geometry–frequency analysis to strengthen the design. In a high-SNR regime, we show that the MMF rate is well approximated by a monotone function of the harmonic mean of the users’ channel gains. This leads to a surrogate MMF objective that depends only on the PASS–MS channel and yields closed-form gradients with respect to antenna positions and carrier frequency. We then build a harmonic-mean-guided proposal-and-refinement algorithm in which the baseline AO–P-SCA scheme provides local exact-MMF refinement and the harmonic-mean gradient provides geometry–frequency trial moves filtered by the same exact-MMF Armijo acceptance rule. Numerical results demonstrate that the proposed PASS–MS–RSMA design achieves a much higher MMF rate and coverage probability than PASS-only, MS-only, and MS–NOMA/OMA benchmarks, and that it also outperforms compact and aperture-matched single-RF phased-array baselines together with an RIS-aided baseline under matched element counts, carrier/bandwidth settings, and total-power budget. They also show that the harmonic-mean-guided variant attains almost the same MMF performance as the exact alternating scheme while requiring substantially lower computational effort.