IEEE 802.11p and LTE as enablers of cognitive vehicle-to-infrastructure communication

Increasing amount of applications for vehicular networks has been recently proposed. Many of them aim to help people to drive more economically and safely. Especially safety related applications require high quality connections for both vehicle-to-vehicle and vehicle-to-infrastructure communications. Currently, ITS-G5 (IEEE 802.11p) can be considered as the most mature standard for vehicular networks. But also the suitability of alternative technologies is being researched, of which Long-Term Evolution (LTE) is among the promising standards for vehicular communication. We made comprehensive measurements for ITS-G5 in various scenarios to see the link performance and reliability in a real-world road environment. For comparison, we also made measurements with LTE. As expected, latest IEEE 802.11p devices have very good performance in terms of delay and line-of-sight range. However, due to the high frequency, the physical obstacles on the link path can be problematic for the signal propagation. LTE could be an interesting solution for vehicular networks, as the range and throughput is larger than with IEEE 802.11p. However, LTE needs a more detailed specification of vehicular communication, and for the most time-critical applications the delays can also be too high.