In this paper, we investigate an uplink communication scenario in which multiple users communicate with an access point (AP) employing non-orthogonal multiple access (NOMA). A pinching antenna, which can be activated at an arbitrary point along a dielectric waveguide, is deployed at the AP to dynamically reconfigure user channels. The objective is to maximize the system sum rate by jointly optimizing the pinching-antenna's position and the users' transmit powers. Two scenarios are considered: one without quality-of-service (QoS) guarantees, and the other with QoS guarantees. In the former case, users transmit at full power, and the antenna position is determined using the particle swarm optimization (PSO) algorithm. In the latter, an alternating optimization approach is adopted, where a low-complexity solution is derived for power allocation, and a modified PSO algorithm is applied to optimize the antenna position. Numerical results show that the proposed pinching-antenna-assisted system significantly improves the sum rate compared to the conventional fixed-antenna architecture. Furthermore, the NOMA-based approach consistently outperforms its TDMA-based counterpart. Finally, the proposed PSO-based method achieves near-optimal performance, particularly when the QoS constraints are moderate.

翻译：本文研究了一种上行链路通信场景，其中多个用户与采用非正交多址接入（NOMA）技术的接入点（AP）进行通信。AP部署了一个夹持天线，该天线可在介质波导的任意点被激活，以动态重构用户信道。目标是通过联合优化夹持天线的位置和用户的发射功率，最大化系统和速率。考虑了两种场景：一种是无服务质量（QoS）保证的场景，另一种是有QoS保证的场景。在前一种情况下，用户以满功率发射，天线位置通过粒子群优化（PSO）算法确定。在后一种情况下，采用交替优化方法，其中推导了一种低复杂度的功率分配方案，并应用改进的PSO算法来优化天线位置。数值结果表明，与传统的固定天线架构相比，所提出的夹持天线辅助系统显著提高了和速率。此外，基于NOMA的方法始终优于其基于TDMA的对应方案。最后，所提出的基于PSO的方法实现了接近最优的性能，特别是在QoS约束适中时。