Center-Fed Pinching Antenna System (C-PASS) Aided Wireless Communications

2026-01-12

AI Summary

This work proposes a centrally fed pinched antenna system (C-PASS) to overcome the limited degrees of freedom inherent in conventional unidirectional feeding antenna systems, which struggle to support high-capacity wireless communication. C-PASS introduces, for the first time, a dual-propagation-direction architecture that doubles the degrees of freedom through controllable power allocation. Three protocols—power splitting, direction switching, and time switching—are designed, accompanied by a tailored optimization framework that jointly optimizes transmit and pinching beamforming. For the time-switching protocol, a closed-form optimal time allocation ratio is derived. The resulting non-convex problems are efficiently solved using techniques such as weighted minimum mean square error reformulation, alternating optimization, and penalty methods. Simulations demonstrate that time switching achieves the best performance at low transmit power, while power splitting and direction switching significantly enhance spectral efficiency at high power due to their higher degrees of freedom.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Multiagent Systems: Agent Communication
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• User Modeling, Personalization and Recommendation: Federated recommendation systems and personalization
• Responsible Web: Measurement, analysis, and circumvention of Web censorship

Abstract

The novel architecture of the center-fed pinching antenna system (C-PASS) is investigated, where the waveguide-fed signal is divided into two propagation directions through controllable power splitting. By doing so, a doubled degree of freedom (DoF) is achieved compared to conventional PASS. Based on the new designed basic signal model of C-PASS, three practical operating protocols for C-PASS are proposed, namely power splitting (PS), direction switching (DS), and time switching (TS). Then, the sum-rate maximization problem for the joint optimization of transmit and pinching beamforming is formulated for each of the proposed protocols. 1) For PS, the highly coupled non-convex problem is first transformed into a tractable form via the weighted minimum mean square error reformulation and solved using the alternating optimization framework; 2) For DS, the above approach is subsequently extended to solve the mixed-integer constraints inherent for DS via the penalty-based algorithm; 3) For TS, the optimization problem can be decomposed into two subproblems and solved using the similar iterative techniques, while its optimal time allocation ratio is derived in closed form. Finally, numerical results reveal that TS is superior in the low-power regime, while PS and DS achieve significantly higher rates in the high-power regime due to the enhanced DoF.

Problem

• center-fed pinching antenna system
• sum-rate maximization
• beamforming optimization
• degree of freedom
• wireless communications

Innovation

• Center-Fed Pinching Antenna System
• Degree of Freedom
• Beamforming Optimization
• Power Splitting
• Time Switching