{
  "abstract": "Pinching-antenna systems (PASS) reconfigure wireless channels by activating radiating elements at selected locations along dielectric waveguides. Port selection is a core issue in improving the performance of multiuser PASS systems. In this paper, we study joint port selection and precoder design for multiuser sum rate maximization, which leads to a large-scale nonconvex mixed-integer problem coupling discrete port selection with continuous precoder design. We propose a discrete diffusion method that does not require optimal or near-optimal port selection solutions as training labels and recasts the resulting optimization problem as sampling from a target distribution. Instead, we learn a potential function from local objective differences between neighboring feasible realizations. The learned potential is incorporated into a Metropolis--Hastings sampling rule to guide a parallel diffusion process while preserving the port selection constraints. Simulation results show that the proposed method approaches exhaustive search within a $0.30\\%$ sum rate gap while achieving over $150\\times$ speedup, and outperforms state-of-the-art methods including greedy and beam search. In particular, it also achieves an $18.8\\times$ speedup over greedy search.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.32258",
  "author_total": 4,
  "authors": [
    {
      "name": "Wenxuan Sun"
    },
    {
      "name": "Mingjie Shao"
    },
    {
      "name": "Yanqing Xu"
    },
    {
      "name": "Ya-Feng Liu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/af3debr06n4t2.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.32258",
  "fulltext_url": null,
  "id": "af3debr06n4t2",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.32258",
  "language": null,
  "licence": "CC0-1.0",
  "licence_label": "CC0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/publicdomain/zero/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cs.IT"
    ],
    [
      "arxiv",
      "math.IT"
    ],
    [
      "openalex",
      "2202|Antenna Design and Analysis"
    ]
  ],
  "openalex": "W7214735535",
  "pdf_url": "https://arxiv.org/pdf/2609.32258",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-26",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/af3debr06n4t2.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:25:17Z",
      "native_id": "2609.32258",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.32258"
    }
  ],
  "subjects": [
    {
      "field": "mathematics",
      "origin": "arxiv:math.IT",
      "subfield": "general"
    }
  ],
  "title": "Discrete Diffusion for Port Selection in Multiuser Pinching-Antenna Systems",
  "title_text": "Discrete Diffusion for Port Selection in Multiuser Pinching-Antenna Systems",
  "type": "preprint",
  "updated_at": "2026-10-30T12:25:17Z",
  "url": "https://research.draconitic.com/paper/af3debr06n4t2",
  "venue": "arXiv",
  "versions": []
}