Mathematical Modeling and Design of RIS Deployment in a RIS-Assisted Metal Cuboid for WAIC Systems

Wireless avionics intra-communications (WAIC) is an emergent research topic, since it can im-prove fuel efficiency and enhance aircraft safety sig-nificantly. However, there are numerous baffles in an aircraft, e.g., seats and cabin bulkheads, resulting in serious blockage and even destroying wireless com-munications. Thus, this paper focuses on the recon-figurable intelligent surface (RIS) deployment issue of RIS-assisted WAIC systems, to solve the block-age problem caused by baffles. We first propose the mirror-symmetric imaging principle for mathemati-cally analyzing electromagnetic (EM) wave propaga-tion in a metal cuboid, which is a typical structure of WAIC systems. Based on the mirror-symmetric imaging principle, the mathematical channel model in a metal cuboid is deduced in detail. In addi-tion, we develop an objective function of RIS's loca-tion and deduce the optimal RIS deployment location based on the geometric center optimization lemma. A two-dimensional gravity center search algorithm is then presented. Simulation results show that the de-signed RIS deployment can greatly increase the re-ceived power and efficiently solve the blockage prob-lem in the aircraft.