Blockchain Tree Powered Green Communication for Efficient and Sustainable Connected Autonomous Vehicles

Connected and Autonomous Vehicles (CAV) is a system of inter-connectivity and communication between smart automated vehicles. Blockchain has emerged as a technology focusing on data security with a decentralized architecture and has been successful to a very high degree. Unfortunately, this technology was not originally meant for low-power IoT devices and is very computationally expensive with high power requirements and a tendency to introduce delays. With the explosion of the Internet of Things (IoT) enabled autonomous vehicles, boosted further by the advent of smart cities, energy requirements have become an issue that can no longer be ignored. As a consequence, research into green technologies has been gaining popularity. With this area of focus, blockchain with its exponential power consumption levels is heavily flawed and thus presents itself as a prime candidate for improvement. In this paper, a framework is proposed to further evolve blockchain technology to integrate it with a semi-centralized data storage mechanism, while keeping network control decentralized. The proposed Blockchain Tree (BCT) approach entails a combination of a tree structure network composed of blockchains, based on a time-based upward data propagation mechanism that optimizes the architecture to reduce communication delay, cut down its high power consumption levels and ensure sustainability in the long run. As is evident in the comparative study, such a blockchain-based network structure offers drastic improvements in terms of speed, energy savings, storage and computation. The proposed model reduces the storage requirement of the blockchain by a factor of 0.17. The energy requirements and time complexity have been optimized by approximately 195% in the early stages of optimization. All the parameters get further optimized by orders of magnitude with more transactions and users.