  With the explosive growth of smart IoT devices at the edge of the Internet,
embedding sensors on mobile devices for massive data collection and collective
environment sensing has been envisioned as a cost-effective solution for IoT
applications. However, existing IoT platforms and framework rely on dedicated
middleware for (semi-) centralized task dispatching, data storage and incentive
provision. Consequently, they are usually expensive to deploy, have limited
adaptability to diverse requirements, and face a series of data security and
privacy issues. In this paper, we employ permissionless blockchains to
construct a purely decentralized platform for data storage and trading in a
wireless-powered IoT crowdsensing system. In the system, IoT sensors use power
wirelessly transferred from RF-energy beacons for data sensing and transmission
to an access point. The data is then forwarded to the blockchain for
distributed ledger services, i.e., data/transaction verification, recording,
and maintenance. Due to coupled interference of wireless transmission and
transaction fee incurred from blockchain's distributed ledger services,
rational sensors have to decide on their transmission rates to maximize
individual utility. Thus, we formulate a noncooperative game model to analyze
this competitive situation among the sensors. We provide the analytical
condition for the existence of the Nash equilibrium as well as a series of
insightful numerical results about the equilibrium strategies in the game.
