Performance Analysis and Comparison of Nonideal Wireless PBFT and RAFT Consensus Networks in 6G Communications

Due to advantages in security and privacy, blockchain is considered a key enabling technology to support 6G communications. Practical Byzantine fault tolerance (PBFT) and RAFT are seen as the most applicable consensus mechanisms (CMs) in blockchain-enabled wireless networks. However, previous studies on PBFT and RAFT rarely consider the channel performance of the physical layer, such as path loss and channel fading, resulting in research results that are far from real networks. Additionally, 6G communications will widely deploy high-frequency signals, such as terahertz (THz) and millimeter wave (mmWave), while performances of PBFT and RAFT are still unknown when these signals are transmitted in wireless PBFT or RAFT networks. Therefore, it is urgent to study the performance of nonideal wireless PBFT and RAFT networks with THz and mmWave signals, to better make PBFT and RAFT play a role in the 6G era. In this article, we study and compare the performance of THz and mmWave signals in nonideal wireless PBFT and RAFT networks, considering rayleigh fading (RF) and close-in free space (FS) reference distance path loss. Performance is evaluated by five metrics: 1) consensus success rate; 2) latency; 3) throughput; 4) reliability gain; and 5) energy consumption. Meanwhile, we find and derive that there is a maximum distance between two nodes that can make CMs inevitably successful, and it is named the active distance of CMs. The results show that the two consensus networks have a lower consensus success rate, higher delay, lower throughput, and lower energy consumption in mmWave than THz. Compared with the wireless RAFT consensus, wireless PBFT consensus has a lower consensus success rate, higher delay, lower throughput, and higher energy consumption. The research results provide important references for the future transmission of THz and mmWave signals in PBFT and RAFT networks.