A Hierarchical Blockchain Aided Proactive Caching Scheme for Internet of Vehicles

The emerging blockchain technology provides a new paradigm for maintaining data integrity and unforgeability in a distributed manner. However conventional public blockchain systems suffer large consensus latency thus cannot be well applied to Internet of Vehicles (IoV) with the high mobility of vehicles and low latency requirement. In addition, not all messages in IoV should be stored in a global ledger. In this paper, we propose a novel Hierarchical Blockchain (HB) which divides the system into two layers and each layer maintains an exclusive ledger. Sensing information of vehicles are recorded in differnet layer according to its influence scope. Furthermore, based on the transactions recorded in the hierarchical blockchain, we design the proactive file duplicate caching scheme considering not only popularities but influence scopes for the enhancement of overall system performance. Simulation results shows the superiority of the proposed architecture compared with conventional vehicular systems, in terms of failure rate, latency and system utility.