Vehicular ad hoc networks (VANETs) are a special case of Mobile ad hoc networks (MANETs), where vehicles are the nodes. Vehicles or nodes share data among themselves in an ad hoc fashion termed Inter-vehicle communication (IVC) or Vehicle to Vehicle (V2V) communication. They also communicate with external networks in infrastructure mode termed Vehicle to Infrastructure (V2I) communication. This data sharing happens through the use of wireless networks, which are formed by moving vehicles equipped with wireless interfaces.
In this experiment, the short-range IEEE 802.11g/ Wi-Fi (ad hoc mode) was used to determine the connection duration time, data rate and the amount of data that can be transferred between two nodes moving at different vehicular speeds. But because only the relative speed matters here, one node was held stationary while the other was moving at: 40, 60 and 90 Km/h on each test. The video shows a demonstration of how the experimental was carried out and the graph shows the results obtained.
Demonstration Video: vanet_test
Since the Wifi operates on an unlicenced band, the interference causes the results to vary hence one cannot rely on a single test set, hence the test needed to be performed a number of times and use the average of the results recorded. In this case for example, at 40Km/h the experiment was performed 3 times; that is, the car drove 3 times past the stationary node (laptop) that was placed on the road side and the total sum of the bandwidths was divided by 3 to get the average.
From the graph above, the results show that as speed increases connection time decreases hence so does the amount of data transfered, even the bandwidth gets lower.