Pinching Antennas in Blockage-Aware Environments: Modeling, Design, and Optimization

TL;DR

This paper develops a deterministic model and optimization algorithms for pinching-antenna systems in obstacle-rich environments, enhancing LoS connectivity and system throughput by leveraging obstacles rather than being hindered by them.

Contribution

It introduces a novel deterministic obstacle model and joint optimization framework for pinching-antenna systems in practical indoor environments, addressing blockage issues.

Findings

Significant throughput improvements over benchmarks.

Enhanced LoS connectivity in obstacle-rich scenarios.

Obstacles can be exploited to reduce interference.

Abstract

Pinching-antenna (PA) systems have recently emerged as a promising member of the flexible-antenna family due to their ability to dynamically establish line-of-sight (LoS) links. While most existing studies assume ideal environments without obstacles, practical indoor deployments are often obstacle-rich, where LoS blockage significantly degrades performance. This paper investigates pinching-antenna systems in blockage-aware environments by developing a deterministic model for cylinder-shaped obstacles that precisely characterizes LoS conditions without relying on stochastic approximations. Based on this model, a special case is first studied where each PA serves a single user and can only be deployed at discrete positions along the waveguide. In this case, the waveguide-user assignment is obtained via the Hungarian algorithm, and PA positions are refined using a surrogate-assisted block-coordinate search. Then, a general case is considered where each PA serves all users and can be continuously placed along the waveguide. In this case, beamforming and PA positions are jointly optimized by a weighted minimum mean square error integrated deep deterministic policy gradient (WMMSE-DDPG) approach to address non-smooth LoS transitions. Simulation results demonstrate that the proposed algorithms significantly improve system throughput and LoS connectivity compared with benchmark methods. Moreover, the results reveal that pinching-antenna systems can effectively leverage obstacles to suppress co-channel interference, converting potential blockages into performance gains.