A Multi-hop Authenticated Proxy Mobile IP Scheme for Asymmetric VANET

Vehicular communications networks are envisioned for the access to drive-thru Internet and IP-based infotainment applications. These services are supported by road-side Access Routers (ARs) that connect the Vehicular Ad hoc Network (VANET) to external IP networks. However, VANETs suffer from asymmetric links due to variable transmission ranges caused by mobility, obstacles, and dissimilar transmission powers, which make them difficult to maintain the bidirectional connections, and to provide the IP mobility required by most IP applications. Moreover, vehicular mobility results in short-lived connections to the AR, affecting the availability of IP services in the VANET. In this paper, we study the secure and timely handover of IP services in the asymmetric VANET, and propose a Multi-hop Authenticated Proxy Mobile IP (MA-PMIP) scheme. MA-PMIP provides an enhanced IP mobility scheme over infrastructureto-vehicle-to-vehicle (I2V2V) communications that uses location and road traffic information. MA-PMIP also reacts depending on the bidirectionality of links to improve availability of IP services. Moreover, our scheme ensures the handover signaling is authenticated when V2V paths are employed to reach the infrastructure, so that possible attacks are mitigated without affecting the performance of the ongoing sessions. Both analysis and extensive simulations in OMNeT++ are conducted, and the results demonstrate that MA-PMIP improves service availability and provides secure seamless access to IP applications in the asymmetric VANET.