Rate Maximization for Downlink Pinching-Antenna Systems

TL;DR

This paper introduces a novel pinching-antenna system that optimizes antenna locations to maximize downlink data rates, demonstrating significant performance improvements over traditional systems through a low-complexity two-stage optimization algorithm.

Contribution

It proposes a new flexible-antenna system with an optimized placement strategy, achieving near-optimal performance with reduced computational complexity.

Findings

Pinching-antenna systems outperform fixed-location systems in simulations.

The proposed algorithm nearly matches exhaustive search performance.

Optimized antenna placement reduces path loss and enhances signal strength.

Abstract

In this letter, we consider a new type of flexible-antenna system, termed pinching-antenna, where multiple low-cost pinching antennas, realized by activating small dielectric particles on a dielectric waveguide, are jointly used to serve a single-antenna user. Our goal is to maximize the downlink transmission rate by optimizing the locations of the pinching antennas. However, these locations affect both the path losses and the phase shifts of the user's effective channel gain, making the problem challenging to solve. To address this challenge and solve the problem in a low complexity manner, a relaxed optimization problem is developed that minimizes the impact of path loss while ensuring that the received signals at the user are constructive. This approach leads to a two-stage algorithm: in the first stage, the locations of the pinching antennas are optimized to minimize the large-scale path loss; in the second stage, the antenna locations are refined to maximize the received signal strength. Simulation results show that pinching-antenna systems significantly outperform conventional fixed-location antenna systems, and the proposed algorithm achieves nearly the same performance as the highly complex exhaustive search-based benchmark.