Pinching-Antenna Systems (PASS) Meet Multiple Access: NOMA or OMA?

TL;DR

This paper investigates a PASS-based two-user communication system under NOMA, FDMA, and TDMA schemes, optimizing beamforming to minimize power while satisfying rate requirements, and compares their performance.

Contribution

It introduces a novel PASS-based system framework with optimized beamforming algorithms for multiple access schemes, highlighting performance advantages over conventional systems.

Findings

PASS outperforms conventional antenna systems in power efficiency.

NOMA outperforms FDMA in the studied scenarios.

TDMA surpasses NOMA for symmetric user rate requirements.

Abstract

A fundamental two-user PASS-based communication system is considered under three MA schemes, namely non-orthogonal multiple access (NOMA), frequency division multiple access (FDMA), and time division multiple access (TDMA). For each MA scheme, a pinching beamforming optimization problem is formulated to minimize the required transmit power for satisfying users' rate requirements. For NOMA and FDMA, a two-stage algorithm is proposed, where the locations of PAs are derived sequentially by using the successive convex approximation (SCA) method and fine-turning phase adjustment. For TDMA, by leveraging the time-switching feature of PASS, the optimal pinching beamforming of each time slot is derived to maximize the served user channel gain. Numerical results are provided to show that: 1) PASS can achieve a significant performance gain over conventional antenna systems, and 2) NOMA consistently outperforms FDMA, while TDMA provides superior performance than NOMA for symmetric user rate requirements.