A Comprehensive Analysis of Packet Delay in Reconfigurable Intelligent Surface-Assisted Communication Networks

Reconfigurable intelligent surface (RIS) technology has been widely used to enhance the performance of wireless communication networks. Specifically, to overcome the blockage issue, the RIS is equipped with passive elements that can steer the wireless signals around the obstacle and construct a virtual line-of-site (LoS) link between the transmitter and receiver. This paper presents a comprehensive analysis of packet delay in RIS-assisted communications, an area that has received limited attention in the literature. Our analysis carefully examines the cascaded wireless channel via RIS to calculate the signal-to-noise ratio (SNR) distribution within Nakagami-m fading channels. Furthermore, we utilize the SNR distribution to develop a novel expression for average packet delay. Our method was evaluated thoroughly through numerical and simulation-based performance testing. We explored the impact of various parameters on average delay performance, including the number of reflecting elements, average SNR, and distance between the user and RIS. Our research indicates that a larger number of passive reflecting elements in an RIS can significantly improve signal reception at the user, leading to better average packet delays. The findings of this paper can be used in multi-user scenarios, where the packet delay is one of the metrics used to address the user-RIS association problem based on the user's delay requirements.