Delay-Tolerant Computation Offloading in Vehicular Networks Based on Local Blockchain

Computation offloading is a promising solution to save the bandwidth and mitigate the load of the cloud server and edge servers by offloading computation tasks to vehicles with idle bandwidth. However, due to the unreliable of vehicles, the privacy of communication in the task offloading in vehicular networks is threatened. The blockchain technology has been widely used in vehicular networks to provision the prompt security of distributed communications. However, the current blockchain structures cannot meet the delay sensitivity of the vehicular networks. On addressing the issues, this paper designs a local blockchain based scheme to protect the privacy of computation offloading in vehicular networks. In specific, we first model the task offloading between the RSU and vehicles as a reverse auction game to motivate the participation of vehicles in the computation tasks. In addition, a local blockchain model is proposed to protect the privacy of the computation offloading. Each RSU holds and manages a local blockchain to record the local auction data, which can realize the offline blockchain blockchain between RSU and vehicles. Finally, simulations are utilized to demonstrate the effectiveness of the proposed scheme.

I. Introduction

Mobile edge computing (MEC) is a promising solution to mitigate the data processing pressure in vehicular networks by offloading computation tasks to nearby edge nodes, so that the performance of the tasks processing can be accelerated [1], [2]. Nevertheless, serious problem arises in the computation offloading in vehicular network, that is, the privacy of the task performers may be leaked since a large amount of data is transmitted through strangers. By recording the interaction data in the decentralized database, Blockchain technology is widely used in the vehicular networks to protect the privacy information of the vehicles and ensure the immutability of the transactions between the edge nodes in the networks. Nevertheless, the vehicles in the vehicular networks are delay sensitive due to the high mobility and the dynamic topology of the networks [3]. Based on such situation, the current blockchain models cannot satisfy the delay requirements of vehicles in initiating the synchronization and consensus process [4]. Therefore, the deployment of blockchain in the vehicular networks is faced with a large number of blockchain transactions waiting for consensus and synchronization, which will greatly increase the delay of blockchain synchronization, and may even cause serious problems such as blockchain forks [5].