Collaborative Caching and Reconfigurable Intelligent Surface for the Sub-THz Mobile System

Enabling high-speed data services with minimal latency over high spectrums represents the evolution direction of the 6G system. This letter introduces a framework for enhancing wireless communication networks and addressing the limitation of the dynamic information accessing and blockage effect through the synergy of caching strategies and reconfigurable intelligent surfaces (RIS) on the sub-Terahertz (sub-THz) frequency band. We derive the achievable rate of the proposed system and show that caching the most popular content is the optimal strategy to maximize the system rate. We introduce a closed-form solution to determine the optimal user distance using a specialized form of the Lambert W function known as the r-Lambert W function.