Power Minimization for Pinching-Antenna Systems: Flexible Hybrid NOMA Perspective

Abstract

Pinching-antenna systems have emerged as a novel promising technology for sixth-generation networks, capable of enhancing spectral efficiency by dynamically creating radiation points and line-of-sight links along a dielectric waveguide. However, the power consumption of such reconfigurable systems remains a critical challenge. This paper investigates a novel flexible hybrid non-orthogonal multiple access (NOMA) strategy for a downlink pinching-antenna system, where the simple two-user scenario is considered for the preliminary analysis of the hybrid NOMA scheme. With the primary objective of minimizing the total transmit power consumption, we formulate the optimization problem that jointly evaluates users’ power allocations and the time-variant locations of the single pinching antenna. To address the coupling between the spatial and power domains, we first derive closed-form power allocation expressions for various channel gain conditions and rigorously establish the feasibility criteria for the hybrid NOMA transmission. Building on this theoretical analysis, a closed-form-assisted reduced-complexity searching algorithm is proposed to determine the optimal antenna locations during different time slots. Numerical results validate the accuracy of the derived closed-form expressions and demonstrate the feasibility of the proposed hybrid NOMA scheme, as well as its ability to achieve superior power-consumption performance compared with conventional benchmarks. Moreover, the results provide valuable analytical insights into the time-varying pinching-antenna positioning, and establish potential applications and a foundational benchmark for hybrid NOMA assisted pinching-antenna systems.