Abstract-In this paper, we present a measurement study of application layer performance in IEEE 802.11p vehicular networks. More specifically, our focus is on active safety applications, which are based on the exchange of beacon messages containing status information between close-by vehicles. We consider two performance metrics relevant to active safety applications: the first is application-layer goodput, which can be used to optimize congestion control techniques aimed at limiting the beaconing load on the wireless channel; the second is the beacon reception rate, which is useful to estimate the level of situation awareness achievable onboard vehicles. Our measurements were conducted using a prototypal, 802.11p compliant communication device developed by NEC, in both stationary and mobile V2V scenarios, and disclosed several useful insights on 802.11p application-level performance. To the best of our knowledge, the ones presented in this paper are the first application-level measurements of IEEE 802.11p based vehicular networks reported in the literature.
I. INTRODUCTIONGiven their potential of considerably reducing car accidents and improving traffic conditions, active safety applications are of primary importance in vehicular networking. This explains the extensive interest this class of applications has gathered in the research and industry community. Despite these intensive efforts, active safety application performance has been mostly evaluated through analysis and simulation. This is mainly due to the fact that the IEEE 802.11p standard for short range vehicular communications, upon which active safety application will be built, is still in draft form. Thus, 802.11p compliant hardware is still difficult to find, and often turns out to be rather expensive.To the best of our knowledge, no application-level IEEE 802.11p measurement study has been reported in the literature so far.