Multi-RIS-aided Cell-Free mmWave Massive MIMO with Short-Packet uRLLC: Passive and Hybrid Active Beamforming

Multi-RIS-aided Cell-Free mmWave Massive MIMO with Short-Packet uRLLC: Passive and Hybrid Active Beamforming | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 11 February 2026 V1 Latest version Share on Multi-RIS-aided Cell-Free mmWave Massive MIMO with Short-Packet uRLLC: Passive and Hybrid Active Beamforming Authors : Ngo Hoang Tu 0000-0003-1944-6056 [email protected] and Kyungchun Lee Authors Info & Affiliations https://doi.org/10.22541/au.177083776.65395796/v1 Published IEEE Transactions on Wireless Communications Version of record Peer review timeline 150 views 99 downloads Contents Abstract Supplementary Material Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Simultaneously meeting high spectral efficiency (SE)-oriented enhanced mobile broadband (eMBB) and ultrareliable and low-latency communication (uRLLC) remains a significant challenge. Given uRLLC requirements, this work investigates the problem of sum-SE maximization in multiple reconfigurable intelligent surfaces-assisted cell-free (CF) millimeter wave massive multiple-input multiple-output systems. The joint optimization problem of passive reflective beamforming (RBF) and hybrid active transceiver beamforming is tackled using a multi-block coordinate descent (MBCD) method, under constraints of transmit power, users' quality-of-service, and constant-modulus characteristics. The subproblems involving analog transceiver processing and passive RBF, associated with constant-modulus constraints, are solved via MBCD-based Riemannian manifold optimization, while the subproblems involving digital transceiver beamforming are addressed using a successive convex approximation framework combined with semidefinite relaxation and Gaussian randomization. To further balance computational complexity, fronthaul overhead, and system performance, a user-centric access point selection scheme is adopted using statistical channel state information. Numerical results demonstrate that the proposed framework outperforms various practical benchmark schemes in terms of user SE. Furthermore, the user-centric CF design achieves a 99.29% reduction in computational complexity with only a 5.49% performance loss compared with full-association CF. Index Terms-Cell-free massive MIMO, reconfigurable intelligent surface (RIS), hybrid beamforming (HBF), millimeterwave (mmWave) communication, ultra-reliable and low-latency communication (uRLLC). Supplementary Material File (manuscriptr1_multiirs_cf_mmwave_mmimo_20260211_vfinal (cleanversion).pdf) Download 2.14 MB Information & Authors Information Version history V1 Version 1 11 February 2026 Peer review timeline Published IEEE Transactions on Wireless Communications Version of Record 1 Jan 2026 Published Copyright This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License Keywords cell-free massive mimo hybrid beamforming (hbf) millimeterwave (mmwave) communication reconfigurable intelligent surface (ris) ultra-reliable and low-latency communication (urllc) Authors Affiliations Ngo Hoang Tu 0000-0003-1944-6056 [email protected] View all articles by this author Kyungchun Lee View all articles by this author Metrics & Citations Metrics Article Usage 150 views 99 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Ngo Hoang Tu, Kyungchun Lee. Multi-RIS-aided Cell-Free mmWave Massive MIMO with Short-Packet uRLLC: Passive and Hybrid Active Beamforming. Authorea . 11 February 2026. DOI: https://doi.org/10.22541/au.177083776.65395796/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . 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