# Operating ITS-G5 DSRC over Unlicensed Bands: A City-Scale Performance Evaluation

## TL;DR

This study evaluates the performance of ITS-G5 vehicular communication systems operating over unlicensed ISM bands, comparing them to licensed DSRC, and finds that 2.4 GHz band offers comparable performance, while 5.8 GHz shows reduced packet delivery.

## Contribution

The paper provides the first comprehensive experimental comparison of ITS-G5 performance over unlicensed bands versus licensed DSRC in a city-scale environment.

## Key findings

- 2.4 GHz band achieves similar performance to licensed DSRC.
- 5.8 GHz band has 30% lower packet delivery rate.
- Operating over unlicensed bands is a viable alternative.

## Abstract

Future Connected and Autonomous Vehicles (CAVs) will be equipped with a large set of sensors. The large amount of generated sensor data is expected to be exchanged with other CAVs and the road-side infrastructure. Both in Europe and the US, Dedicated Short Range Communications (DSRC) systems, based on the IEEE 802.11p Physical Layer, are key enabler for the communication among vehicles. Given the expected market penetration of connected vehicles, the licensed band of 75 MHz, dedicated to DSRC communications, is expected to become increasingly congested. In this paper, we investigate the performance of a vehicular communication system, operated over the unlicensed bands 2.4 GHz - 2.5 GHz and 5.725 GHz - 5.875 GHz. Our experimental evaluation was carried out in a testing track in the centre of Bristol, UK and our system is a full-stack ETSI ITS-G5 implementation. Our performance investigation compares key communication metrics (e.g., packet delivery rate, received signal strength indicator) measured by operating our system over the licensed DSRC and the considered unlicensed bands. In particular, when operated over the 2.4 GHz - 2.5 GHz band, our system achieves comparable performance to the case when the DSRC band is used. On the other hand, as soon as the system, is operated over the 5.725 GHz - 5.875 GHz band, the packet delivery rate is 30% smaller compared to the case when the DSRC band is employed. These findings prove that operating our system over unlicensed ISM bands is a viable option. During our experimental evaluation, we recorded all the generated network interactions and the complete data set has been publicly available.