# RF-Assisted Free-Space Optics for 5G Vehicle-to-Vehicle Communications

## TL;DR

This paper proposes a hybrid RF-assisted FSO system for vehicle-to-vehicle communications, using RF signals to align laser sources and mitigate misalignment issues caused by high mobility, thereby enabling reliable high-data-rate V2V links.

## Contribution

It introduces a novel RF-assisted FSO architecture that improves alignment and performance in high-mobility V2V scenarios, addressing a key challenge in optical communication.

## Key findings

- RF-assisted pointing significantly reduces misalignment errors.
- Simulation results show improved link reliability in high mobility.
- The system enables FSO to be viable for V2V communications.

## Abstract

Vehicle-to-Vehicle (V2V) communications are being proposed, tested and deployed to improve road safety and traffic efficiency. However, the automotive industry poses strict requirements for safety-critical applications, that call for reliable, low latency and high data rate communications. In this context, it is widely agreed that both Radio-Frequency (RF) technologies at mmWaves and Free-Space Optics (FSO) represent promising solutions, although their performances are severely degraded by transmitter-receiver misalignment due to the challenging high-mobility conditions. By combining RF and FSO technologies, this paper proposes a FSO-based V2V communication system where the pointing coordinates of laser sources are based on vehicle's information exchanged over a reliable low-rate RF link. Numerical simulations demonstrate that such compensation mechanism is mandatory to counteract the unavoidable misalignments induced by vehicle dynamics, and thus to enable FSO technology for V2V communications even in high mobility scenarios.