HARDWARE IMPLEMENTATION OF RIS-BASED COMMUNICATION SYSTEM

Abstract

This thesis presents the design, simulation, and hardware implementation of a Reconfigurable Intelligent Surface (RIS) based communication system at 6 GHz. The RIS technology can solve signal blockage problems in dense urban areas by redirecting electromagnetic (EM) waves through programmable metasurfaces. A simulation model was created using quasistatic methods, to predict reflection patterns and optimize codebook selection for beamforming. Two approaches were used: a brute-force method and a masking technique that reduced computation needs while maintaining accuracy. The hardware prototype was built as an unit cell array with two PIN diodes per cell for 2-bit phase control, managed by the 8 × 8 Field-Programmable Gate Array (FPGA) using serial-in-parallel-out shift registers. Control system tests showed successful state changes with switching delays of about 100 μs. Simulations of aerial RIS platforms were also conducted, where Unmanned Aerial Vehicle (UAV) positions were optimized across different environments using a Grey Wolf Optimizer (GWO) algorithm. The practical UAV simulation results show that the RIS technology can improve wireless communication in challenging environments. This work provides a starting point for future development of more advanced systems, including 3-bit RIS designs, alternative modeling approaches, and better positioning and beamforming methods for aerial platforms.