Optimizing Curved EM Skins for Opportunistic Relaying in Vehicular Networks

TL;DR

This paper proposes a novel static curved electromagnetic skin (CEMS) design for vehicles, transforming them into passive relays to improve communication in vehicular networks, especially when direct paths are blocked.

Contribution

It introduces a new phase profile design method for static CEMS based on traffic-influenced angle distributions, optimizing spectral efficiency and coverage probability.

Findings

Significant improvements in spectral efficiency when direct paths are blocked.

Enhanced coverage probability with properly designed CEMS.

Validation of the proposed optimization method through numerical simulations.

Abstract

Electromagnetic skins (EMSs) are recognized for enhancing communication performance, spanning from coverage to capacity. While much of the scientific literature focuses on reconfigurable intelligent surfaces that dynamically adjust phase configurations over time, this study takes a different approach by considering low-cost static passive curved EMS (CEMS)s. These are pre-configured during manufacturing to conform to the shape of irregular surfaces, e.g., car doors, effectively transforming them into anomalous mirrors. This design allows vehicles to serve as opportunistic passive relays, mitigating blockage issues in vehicular networks. This paper delves into a novel design method for the phase profile of CEMS based on coarse a-priori distributions of incident and reflection angles onto the surface, influenced by vehicular traffic patterns. A penalty-based method is employed to optimize both the average spectral efficiency (SE) and average coverage probability, and it is compared against a lower-complexity and physically intuitive modular architecture, utilizing a codebook-based discrete optimization technique. Numerical results demonstrate that properly designed CEMS lead to a remarkable improvements in average SE and coverage probability, namely when the direct path is blocked.