expires, all the received messages respect the imposed time
constraints and therefore the analysis of the average delay
becomes less important.
The beaconing reception probabilities for the studied
solutions can be observed in Figure 1.1. To better understand
the behavior of each mechanism, Figure 1.2 shows the
average CW as a function of vehicular density.
Vehicular Density [veh/km]
Figure 1.1. Beaconing reception probability (including expired
beacons) using IEEE 802.11p and the five mechanisms described in
this chapter for different vehicular densities (the 95% confidence
interval is also shown)
The first thing that can be noted from the data is that all
the five solutions show better performance than the basic
mechanism, with a difference that can reach more than 10%.
Estimating the number of neighbors using the received
beacons gives the best results for a vehicular density under
60 cars/km. The idle time approach also gives similar results,