{
  "abstract": "This letter investigates a cell-free massive MIMO system with $L$ access points (APs), each employing a small fixed-form-factor, uniform linear array of $N$ potentially closely spaced antennas. Utilizing multiport communication theory, we analyze the impact of mutual coupling on uplink and downlink spectral efficiency (SE) under various impedance-matching strategies. We compare two deployment regimes: ($i$) increasing $N$ while $L$ is kept fixed, and ($ii$) increasing $N$ while fixing the total antenna count $M = NL$. Numerical results show that, with a full matching network, mutual coupling itself becomes beneficial when an AP serves several user equipments, which is the typical operating regime of user-centric cell-free networks. Furthermore, with full matching, antenna densification can enhance SE or allow for a reduction in the number of APs without performance loss. Since full matching networks remain of manageable size in the small arrays of distributed APs, unlike in large centralized arrays, cell-free networks offer a natural setting for exploiting mutual coupling.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2611.03193",
  "author_total": 3,
  "authors": [
    {
      "name": "Erind Tufa"
    },
    {
      "name": "Antonio A. D'Amico"
    },
    {
      "name": "Luca Sanguinetti"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/93vx6xhwjqffp.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2611.03193",
  "fulltext_url": null,
  "id": "93vx6xhwjqffp",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2611.03193",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cs.IT"
    ],
    [
      "arxiv",
      "eess.SP"
    ],
    [
      "arxiv",
      "math.IT"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2611.03193",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-02",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/93vx6xhwjqffp.ris",
  "sources": [
    {
      "first_seen": "2026-11-03T12:21:14Z",
      "native_id": "2611.03193",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2611.03193"
    }
  ],
  "subjects": [
    {
      "field": "mathematics",
      "origin": "arxiv:math.IT",
      "subfield": "general"
    }
  ],
  "title": "Harnessing Mutual Coupling in Cell-Free mMIMO",
  "title_text": "Harnessing Mutual Coupling in Cell-Free mMIMO",
  "type": "preprint",
  "updated_at": "2026-11-05T15:20:28Z",
  "url": "https://research.draconitic.com/paper/93vx6xhwjqffp",
  "venue": "arXiv",
  "versions": []
}