RIS Control through the Lens of Stochastic Network Calculus: An O-RAN Framework for Delay-Sensitive 6G Applications Adamuz Hinojosa, Óscar Ramón Zanzi, Lanfranco Sciancalepore, Vincenzo Di Renzo, Marco Costa-Perez, Xavier Stochastic Network Calculus Smart Surfaces RIS Funding for open access charge: Universidad de Granada / CBUA. This work is part of the project PID2022-137329OB-C43 funded by MICIU/AEI/10.13039/501100011033 and by FEDER, EU, and also part of the project C-ING-306-UGR23 funded by Consejería de Universidad, Investigación e Innovación and by ERDF Andalusia Program 2021-2027. Furthermore, it has been partially supported by the MultiX project from Smart Networks and Services Joint Undertaking (SNS JU) under the European Union’s Horizon Europe research and innovation programme (Grant 101192521). Reconfigurable Intelligent Surfaces (RIS) enable dynamic electromagnetic control for 6G networks, but existing control schemes lack responsiveness to fast-varying network conditions, limiting their applicability for ultra-reliable low latency communications. This work address uplink delay minimization in multi-RIS scenarios with heterogeneous per-user latency and reliability demands. We propose Delay-Aware RIS Orchestrator (DARIO), an O-RAN-compliant framework that dynamically assigns RIS devices to users within short time windows, adapting to traffic fluctuations to meet per-user delay and reliability targets. DARIO relies on a novel Stochastic Network Calculus (SNC) model to analytically estimate the delay bound for each possible user–RIS assignment under specific traffic and service dynamics. These estimations are used by DARIO to formulate a Nonlinear Integer Program (NIP), for which an online heuristic provides near-optimal performance with low computational overhead. Extensive evaluations with simulations and real traffic traces show consistent delay reductions up to 95.7% under high load or RIS availability. 2026-03-11T10:15:49Z 2026-03-11T10:15:49Z 2026-03-01 journal article Published version: Adamuz Hinojosa, O. R.; Zanzi, L.; Sciancalepore, V. [et al]. (2026). RIS Control through the Lens of Stochastic Network Calculus: An O-RAN Framework for Delay-Sensitive 6G Applications. IEEE Transactions on Wireless Communications. DOI: 10.1109/TWC.2026.3672338 1558-2248 1536-1276 https://hdl.handle.net/10481/112030 10.1109/TWC.2026.3672338 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ open access Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License IEEE