SatBFT: An Efficient and Scalable Consensus Protocol for Blockchain-Enabled Space-Air-Ground Integrated Network

The Space-Air-Ground Integrated Network (SAGIN) is a pivotal direction for the advancement of the sixth generation mobile communication systems (6G), and blockchain technology has been recognized as a potential solution for secure spectrum sharing within SAGIN. However, the implementation of wireless blockchain networks encounters significant challenges, particularly limited throughput and scalability. These challenges are primarily due to the limitations of existing consensus protocols, which were designed for general distributed systems, struggling to adapt to highly dynamic SAGIN scenarios. An efficient and secure spectrum sharing framework can be established by leveraging delegated proof of stake (DPoS) and practical byzantine fault tolerance (PBFT). Accordingly, we propose SatBFT, a scalable consensus protocol that emphasizes the inclusion of satellites and employs a DPoS-PBFT mechanism tailored to SAGIN. The protocol is carefully designed to accommodate the various links in SAGIN and to manage coexisting interference. By adopting a multi-layer architecture, SatBFT introduces a comprehensive consensus framework that incorporates radio environment sensing, dynamic behavior evaluation and efficient block generation. Simulations based on the proposed security model, latency model, and spectrum utilization model confirm that SatBFT significantly enhances the overall performance of blockchain in SAGIN, achieving an optimal balance between efficiency, scalability, and security.