Secure and Efficient Transmission in Hybrid Sparse RIS-Enabled Internet of Robotic Things

The convergence of robotics and IoT has enabled the Internet of Robotic Things (IoRT), where autonomous devices collaborate to perform tasks. Deploying IoRT in 5G/6G networks faces three challenges: (i) securing communication against eavesdroppers, (ii) ensuring connectivity under link blockage, and (iii) achieving energy- and hardware-efficient scalability. Passive reconfigurable intelligent surfaces (RIS)-based solutions suffer from double fading, limiting secrecy and reliability. To address these challenges, we propose a Hybrid RIS (HRIS)-assisted secure transmission framework, where a Base Station (BS) communicates with IoRT devices under eavesdropping by jointly exploiting active and passive RIS elements. We design a sparse HRIS that activates only a selected subset of elements, reducing power and hardware cost without compromising security. We jointly optimize HRIS configuration and BS beamforming to maximize secrecy rate under power constraints. We develop a contextual multi-armed bandit (MAB) algorithm-based solution that autonomously learns secrecy strategies. Simulations show that MAB-based Sparse HRIS achieves up to 86.6% (31.9%) secrecy-rate gain over passive (active) RIS and up to 184.5% energy-efficiency than active RIS, offering a secure solution for IoRT in future 5G/6G systems.

Recommended citation: G. Singh, S. Kurma, D. Roy, and V. Chaudhary, "Secure and Efficient Transmission in Hybrid Sparse RIS-Enabled Internet of Robotic Things," in Proc. 2026 24th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt), Columbus, OH, USA, 2026, pp. 1–8, doi: 10.23919/WiOpt71098.2026.11568220. https://doi.org/10.23919/WiOpt71098.2026.11568220