Research On Transmission Mechanism In Vehicular Named Data Networking

With the rapid development of modern transportation and automobile industry, Motor vehicle population is increasing rapidly in China. Especially with the improvement of people's consumption level, the private cars are spread rapidly in our country. As a kind of network which improves road safety and transportation efficiency, and also meet the demand of driving people with the entertainment services, vehicular networks has been concerned widely.Vehicular networks are dynamic systems where nodes move frequently, node mobility cause frequent connectivity disruptions and network changes suddenly, the connectivity between vehicles are intermittent, yet the traditional IP's point-to-point, location based communication model does not fit well in vehicular networks. Named Data Networking(NDN) is a newly proposed architecture for the future Internet, which points out a new direction to design vehicular networks. Instead of forwarding packets to a specific moving car, named data networking aims to fetch specific pieces of data from multiple potential carriers of the data, thus NDN's request/reply exchange model seems ideally suited for the need of V2 V data exchanges. In this thesis, we analyzed and discussed NDN architecture for vehicular networks, and further research on transmission mechanism.Firstly, aiming at the forwarding strategy of vehicular named data networking so far mainly concern about the distances between vehicles only, which may cause low success rate and long transmission delay of multi-chunk data, we proposed an attribute based interest forwarding mechanism. Considering the vehicle current running status, the strategy introducing multiple forwarding conditions, we also classify the attribute of vehicular data, using three scale AHP method to adjust the selection criteria weights, to accomplish the dynamic selection of the forwarding nodes. The simulation analysis shows that the proposed approach improves the success rate and lower the transmission delay with the guarantee of interest spread efficiency.Secondly, aiming at the transmission fail caused by vehicles with specific PIT(Pending Interest Table) entries get out of the signal range in vehicular scenarios, we proposed a dynamic pending interest table management mechanism. When hear the pending forward interest forwarded by others, instead of just cancel the forwarding, vehicle will dynamically choose to add the interest into PIT entries regardless whether forward the interest itself or not. Vehicles will clean up the PIT periodically and dynamically to keep PIT size in the acceptable range. The simulation analysis shows that the proposed approach improves success rate and robustness of data packets retrieve while keep the number of PIT entries under control.