Age Minimization in Outdoor and Indoor Communications With Relay-Aided Dual RIS

In this letter, we investigate an outdoor and indoor wireless communication network with the assistance of a relay-aided double-sided reconfigurable intelligent surface (RIS). A scheduling problem is considered at the outdoor access point (AP) to minimize the sum of age of information (AoI). To serve the indoor users and further enhance the wireless link quality, a double-sided RIS with relay is utilized. Since the formulated problem is non-convex with highly-coupled variables, a successive convex approximation (SCA) and penalty based alternating optimization (AO) algorithm with difference of convex (DC) functions is proposed to solve it in an iterative manner. Finally, simulation results show the effectiveness and significant performance improvement in terms of AoI of the proposed algorithm compared with other baselines.