Cooperative vehicular communications at intersections over Nakagami-m fading channels

In this paper, we study vehicular communications (VCs) at road intersections. We investigate three transmission schemes: direct transmissions (DT), relay transmissions (RT) and hybrid transmissions (HT), in the presence of interference. We model the interferer vehicle locations as a Poisson point process. Using tools from stochastic geometry, we compute the outage probability for the three transmission schemes considering Nakagami-m fading channels. We consider line of sight (LOS) scenarios and non-line of sigh (NLOS) scenarios. We derive the outage probability when the receivers are on the roads (as a vehicle), or outside the roads (as an infrastructure). We show that RT is useful only when DT is not possible. We also show that, in LOS scenario, DT is better for high densities of vehicles. We show that HT has better performance for low densities of vehicles and low data rates regardless of the scenario considered. Surprisingly, we find that NLOS scenarios outperform LOS scenarios at intersections. Finally, we show that the best relay position in RT is at mid-distance between the source and the destination whereas the best relay in HT is close to the destination. Analytical results are validated by Monte-Carlo simulations.