Energy-Efficient Design for Downlink Pinching-Antenna Systems with QoS Guarantee

TL;DR

This paper proposes an energy-efficient design for downlink pinching-antenna systems with QoS guarantees, optimizing antenna placement, power, and time allocations to outperform traditional systems.

Contribution

It introduces a joint optimization framework for antenna positioning, power, and time allocation in pinching-antenna systems, addressing a non-convex EE maximization problem.

Findings

Proposed method outperforms fixed-antenna systems in energy efficiency.

Optimal antenna placement improves system feasibility and performance.

Iterative semi-analytical solutions effectively solve the joint optimization problem.

Abstract

Pinching antennas have recently garnered significant attention due to their ability to dynamically reconfigure wireless propagation environments. Despite notable advancements in this area, the exploration of energy efficiency (EE) maximization in pinching-antenna systems remains relatively underdeveloped. In this paper, we address the EE maximization problem in a downlink time-division multiple access (TDMA)-based multi-user system employing one waveguide and multiple pinching antennas, where each user is subject to a minimum rate constraint to ensure quality-of-service. The formulated optimization problem jointly considers transmit power and time allocations as well as the positioning of pinching antennas, resulting in a non-convex problem. To tackle this challenge, we first obtain the optimal positions of the pinching antennas. Based on this, we establish a feasibility condition for the system. Subsequently, the joint power and time allocation problem is decomposed into two subproblems, which are solved iteratively until convergence. Specifically, the power allocation subproblem is addressed through an iterative approach, where a semi-analytical solution is obtained in each iteration. Likewise, a semi-analytical solution is derived for the time allocation subproblem. Numerical simulations demonstrate that the proposed pinching-antenna-based strategy significantly outperforms both conventional fixed-antenna systems and other benchmark pinching-antenna schemes in terms of EE.