Cooperative infrastructure discovery through V2X communication

Opportunistic applications like software or digital maps updates and vehicle diagnostic reporting may require limited Intermittent Internet access. Hence, those applications can benefit of the existing Infrastructure already deployed. Moreover, the knowledge of the location of these APs, especially the ones offering free access, can help gaining time and make more accurate decision when data has to be transmitted. In this paper, we propose a Cooperative Infrastructure Discovery Protocol, called CIDP. It allows vehicles to gather information about encountered APs through direct communications with the infrastructure (Infrastructure to Vehicle(I2V)/Vehicle to Infrastructure(V2I) communications) and mainly exchange it with opportunistically encountered vehicles (Vehicile to Vehicle (V2V) communications). We studied the performances of CIDP through simulation. Results show that it improves the discovery process of APs thanks to the dissemination of the Infrastructure information cooperatively between equipped vehicles through V2V communications. Then, in order to reduce the induced overhead, we proposed two variants of CIDP, CIDP-D (CIDP with Density consideration) and CIDP-DH (CIDP-D with History consideration) in which the broadcast decisions are dynamically taken based on the neighboring vehicles encountered during a set of time frames. Further simulations showed that, with a judicious configuration of its parameters, CIDP-D can provide results similar to those of CIDP with lower overhead. However, with CIDP-DH, the best results are obtained with a single frame which is probably due to the high dynamism of the network making the knowledge of previous history irrelevant.