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
$O(\log N\log \Gamma)$
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 as well as node recovery mechanisms to ensure efficiency, fault tolerance, persistence, and liveness. The worst-case runtime of
$\mathit {wChain}$
is upper bounded by
$O(f\log N\log \Gamma)$
, 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. The results not only demonstrate the nice properties of
$\mathit {wChain}$
, but also point to a large new space for the exploration of blockchain protocols in wireless networks.