  Blockchain has emerged as a promising technology that can guarantee data
consistency and integrity among distributed participants. It has been used in
many applications of the Internet of Things (IoT). However, since IoT
applications often introduce a massive number of devices into blockchain
systems, the efficiency of the blockchain becomes a serious problem. In this
article, we analyze the key factors affecting the efficiency of blockchain.
Unlike most existing solutions that handle this from the computing perspective,
we consider the problem from the communication perspective. Particularly, we
propose a coordinated satellite-terrestrial network to create efficient
blockchains. We also derive a network scheduling strategy for the proposed
architecture. Simulation results demonstrate that the proposed system can
support blockchains for higher efficiency. Moreover, several open research
issues and design challenges will be discussed.
