Blockchain-based reliable task offloading framework for edge-cloud cooperative workflows in IoMT

With the evolution of Internet of Medical Things (IoMT), the number of terminal devices has grown exponentially. This has led to a substantial influx of health-related data, which is transmitted among various distributed terminal devices and edge-cloud servers. This data is subsequently processed to provide real-time medical services and assistance. Nevertheless, within this context, challenges such as user mobility, stringent requirements, heterogeneous nature of resources, and data security concerns pose substantial obstacles for the task offloading problem. To address these challenges, we introduce a Blockchain-based Reliable Task Offloading (BRTO) framework for edge-cloud cooperative workflows in IoMT system. Specifically, we establish a three-layer edge-cloud cooperative framework that leverages blockchain and Software Defined Network (SDN) to enhance task offloading efficiency and security. Subsequently, we formulate and model the task offloading problem as an optimization model that takes into account latency, energy efficiency, and security. Then, we propose a two-phase offloading algorithm based on blockchain smart contracts to solve the problem. It involves the use of an enhanced Ant-based algorithm for optimal task offloading decisions and the creation of an SDN-based smart contract to guarantee data security. Comprehensive experimental results illustrate that BRTO outperforms other strategies in terms of scalability, robustness, efficiency, and reliability.