A Network Coding Collaborative Download Scheme for Platoon-Based VANETs

Platoon-based Vehicular Ad-hoc Networks (VANETs) can significantly improve the road capacity and facilitate the potential cooperative communication applications. However, the communication links between platoon-based vehicles and the roadside unit (RSU) are unstable, which decrease the throughput and increase the delay, and cause the infotainment resources cannot be downloaded quickly. In this paper, we propose a collaborative download strategy in platoon-based VANETs to solve the problems. On the basis of RSUs support simultaneous communication with multiple vehicles, when a demand vehicle need to download multimedia files, we use the collaborative download request management mechanism to request other vehicles in the same RSU coverage area to participate in the collaborative download process. Besides, to decrease the download time, we divide the required multimedia files into multiple data packets. After the RSUs encode the data packets via linear network coding, the cooperative vehicles forward the received encoded packets to the demand vehicle. We also research the impact of speed and file size on the performance of cooperative download strategy. The simulation results show that the proposed cooperative download strategy can effectively increase throughput and reduce the downloading completion time when download multimedia files, especially when the size of multimedia files is large and the speed of platoon-based vehicles is fast.