  Blockchain has been deemed as a promising solution for providing security and
privacy protection in the next-generation wireless networks. Large-scale
concurrent access for massive wireless devices to accomplish the consensus
procedure may consume prohibitive communication and computing resources, and
thus may limit the application of blockchain in wireless conditions. As most
existing consensus protocols are designed for wired networks, directly apply
them for wireless users may exhaust their scarce spectrum and computing
resources. In this paper, we propose AirCon, a byzantine fault-tolerant (BFT)
consensus protocol for wireless users via the over-the-air computation. The
novelty of AirCon is to take advantage of the intrinsic characteristic of the
wireless channel and automatically achieve the consensus in the physical layer
while receiving from the end users, which greatly reduces the communication and
computational cost that would be caused by traditional consensus protocols. We
implement the AirCon protocol integrated into an LTE system and provide
solutions to the critical issues for over-the-air consensus implementation.
Experimental results are provided to show the feasibility of the proposed
protocol, and simulation results to show the performance of the AirCon protocol
under different wireless conditions.
