Implementing Practical Byzantine Fault Tolerance Over Cellular Networks

Blockchain has shown significant potential as a key enabler in privacy and security in the forthcoming 6G wireless network, due to its distributed and decentralized characteristics. Practical Byzantine fault tolerance (PBFT) emerges as a prominent technology for deployment in wireless networks due to its attributes of low latency, high throughput, and minimal computational requirements. However, the high complexity of communication is the bottleneck of PBFT for achieving high scalability. To tackle this problem, this paper proposes a novel framework of PBFT, where the inter-node communication during the normal case operation is completed through base stations. The uplink and downlink communication between the base station and nodes are modelled based on the signal-to-interference-plus-noise ratio (SINR) threshold. A novel 'timeout' mechanism is incorporated to reduce the communication complexity. The performance is evaluated by metrics including consensus success probability, communication complexity, view change delay, view change occurrence probability, consensus delay, consensus throughput and energy consumption. The numerical results show that the proposed scheme achieves higher consensus success probability and throughput, lower communication complexity and consensus delay compared to the conventional PBFT. The results of view change delay and view change occurrence probability and the optimal configuration provide analytical guidance for the deployment of wireless PBFT networks.