wChain: A Fast Fault-Tolerant Blockchain Protocol for Multihop Wireless Networks

This paper presents $mathit{wChain}$, a blockchain protocol specifically designed for multihop wireless networks that deeply integrates wireless communication properties and blockchain technologies under the realistic SINR model. We adopt a hierarchical spanner as the communication backbone to address medium contention and achieve fast data aggregation within $O(log NlogGamma)$ slots where $N$ is the network size and $Gamma$ refers to the ratio of the maximum distance to the minimum distance between any two nodes. Besides, $mathit{wChain}$ employs data aggregation and reaggregation, and node recovery mechanisms to ensure efficiency, fault tolerance, persistence, and liveness. The worst-case runtime of $mathit{wChain}$ is upper bounded by $O(flog NlogGamma)$, where $f=lfloor frac{N}{2} rfloor$ is the upper bound of the number of faulty nodes. To validate our design, we conduct both theoretical analysis and simulation studies, and the results only demonstrate the nice properties of $mathit{wChain}$, but also point to a vast new space for the exploration of blockchain protocols in wireless networks.