On the Scalability of Energy in Wireless RF Powered Internet of Things

Wireless RF power transfer requires the deployment of multiple energy transmitters (ETs) to cover an entire area of interest. This letter aims at bounding the minimum cumulative power that ETs need to inject into the network, such that the recipient nodes harvest sufficient power to operate. The main findings are that, in the worst case, this scales as O(s
^1-α/2
), where s and α are the number of ETs and the channel path loss. That is, the overall power decreases with the number of ETs. It is also shown that sophisticated design for power transmission can further improve the scalability by s
^-1
.