RIS-assisted Seamless Connectivity in Wireless Multi-Hop Relay Networks
Peini Yi, Wenchi Cheng, Jingqing Wang, Wei Zhang
TL;DR
This work tackles seamless connectivity in wireless multi-hop relay networks by integrating Reconfigurable Intelligent Surfaces (RIS) into a UAV-based MANET where every node carries an RIS. It develops a distributed RIS-DCF MAC that extends RTS/CTS to RIS-enabled frames, decomposes multi-hop routes into dual-hop and single-hop segments, and analyzes a two-hop access model and multi-hop scenarios to quantify throughput gains. The key contributions are the RIS-enabled network model, the RIS-DCF protocol with RIS-channel reservation and NAV-based coordination, and an analytical framework predicting end-to-end throughput improvements and their dependence on RIS size, hop count, and network density; results show RIS can significantly boost throughput and diversity in sparse networks, while adaptive switching between RIS and conventional channels is beneficial in denser scenarios. The work provides practical insights for deploying RIS in distributed UAV networks, highlighting RIS element scaling, mobility constraints, and protocol design necessary to realize seamless multi-hop connectivity in non-stationary ad hoc settings.
Abstract
In recent years, reconfigurable intelligent surfaces (RIS) have garnered significant attention for their ability to control the phase shifts in reflected signals. By intelligently adjusting these phases, RIS can establish seamless direct paths between communication devices obstructed by obstacles, eliminating the need for forwarding and significantly reducing system overhead associated with relaying. This capability is crucial in multi-hop ad hoc networks requiring multiple relay steps. Consequently, the concept of incorporating multi-hop RIS into wireless multi-hop relay networks has emerged. In this paper, we propose a novel network model where each UAV communication node is equipped with a RIS, facilitating seamless connections in multi-hop relay wireless networks. We analyze the performance of this model by integrating RIS-assisted physical layer modeling into the seamless connection network framework and conducting a detailed comparative analysis of RIS-assisted and conventional connections. At the medium access layer, we introduce a RIS-DCF MAC protocol based on the IEEE 802.11 distributed coordination function (DCF), modeling the medium access process as a two-hop access scenario. Our results demonstrate that the seamless connections and diversity gain provided by RIS significantly enhance the performance of multi-hop relay wireless networks.