Throughput-Efficient Blockchain for Internet-of-Vehicles

Internet-of-Vehicle (IoV) is empowering smart vehicles with data collection and sharing capabilities, and blockchains have been introduced to manage the IoV data due to many advantages, including decentralization, security, reliability, and scalability. Nevertheless, existing IoV blockchain models suffer from poor security against collusion attacks instigated by malicious blockchain miners typically represented by roadside units (RSUs). To address this problem, additional block verifiers, e.g., vehicles, can be recruited during block verification, which enhances security but also can lead to the reduced throughput. Therefore, in this paper, we propose a resource management scheme for IoV blockchains to enhance the system security while maximizing the throughput by optimizing contributed computing resources from RSUs and recruited vehicles. We show that the optimal strategies of RSUs and vehicles can be found through the Karush-Kuhn-Tucker (KKT) conditions and verify (using simulations) that our scheme achieves the higher throughput with enhanced security compared to the existing IoV blockchains.

I. Introduction

IoV facilitates interconnections and interactions among smart vehicles, including data exchange and storage. Traditional centralized approaches to manage data collection and sharing in IoV have many limitations, such as the single point of failure, privacy leakage, low reliability, poor scalability, and absence of transparency. Instead, a distributed ledger - blockchain, has been recently proposed to enhance security, reliability and scalability, and preserve privacy of data management in IoV [1]. In blockchains, the data collected and exchanged by the vehicles are converted into blocks and verified by decentralized blockchain miners, i.e. RSUs, based on a predefined consensus algorithm. Due to low throughput of public consensus algorithms, e.g., proof-of-work (PoW) or proof-of-stake (PoS) [2], the IoV blockchains usually adopt consortium blockchain algorithms, such as delegated PoS (DPoS) [3] or practical Byzantine Fault Tolerance (pBFT) [4]. However, such consensus algorithms have a rather poor security - less than 33% of malicious miners can be tolerated. The main reason is that due to the small size of consortium blockchains, miners can easily collude with each other to falsely verify or reject the block [3].