COBRA: A Collaboration Based Reinforcement Mechanism for Mass Transmission in VANETs

Vehicular ad hoc networks (VANETs) allow vehicles to form self-organized networks while driving, which can offer cheap methods to access the Internet for the passengers. When the scope of VANETs becomes larger, it’s often needed to forward massive data to some fixed Internet APs distributed in the city. There are a lot of routing algorithms proposed to reduce the message propagation delay and also reduce bandwidth consumption on VANETs, but most of which are under the assumption that the bandwidth between vehicles is unlimited so massive data can be forwarded instantaneously; it is verified that this can lead poor transmission performances when implemented. The authors propose a reinforcing mechanism COBRA to forward massive data in VANETs. The COBRA mechanism focuses on the incomplete data transmitting problem brought by high driving speed and limited wireless communication range. The mechanism utilizes the stable topology characteristic of vehicles running in the same directions to prolong the opportunistic transmitting time, and also use erasure coding technology to deal with the uncertain factors in the “meeting-forwarding” processes. The simulation results show that, when data are large, or when bandwidth is limited, the routing method with the reinforcing mechanism can outperform the existing VANET routing protocols.