  Blockchain is built on a peer-to-peer network that relies on frequent
communications among the distributively located nodes. In particular, the
consensus mechanisms (CMs), which play a pivotal role in blockchain, are
communication resource-demanding and largely determines blockchain security
bound and other key performance metrics such as transaction throughput, latency
and scalability. Most blockchain systems are designed in a stable wired
communication network running in advanced devices under the assumption of
sufficient communication resource provision. However, it is envisioned that the
majority of the blockchain node peers will be connected through the wireless
network in the future. Constrained by the highly dynamic wireless channel and
scarce frequency spectrum, communication can significantly affect blockchain's
key performance metrics. Hence, in this paper, we present wireless blockchain
networks (WBN) under various commonly used CMs and we answer the question of
how much communication resource is needed to run such a network. We first
present the role of communication in the four stages of the blockchain
procedure. We then discuss the relationship between the communication resource
provision and the WBNs performance, for three of the most used blockchain CMs
namely, Proof-of-Work (PoW), practical Byzantine Fault Tolerant (PBFT) and
Raft. Finally, we provide analytical and simulated results to show the impact
of the communication resource provision on blockchain performance.
