  The performance of wireless communication is fundamentally constrained by the
limited battery life of wireless devices, whose operations are frequently
disrupted due to the need of manual battery replacement/recharging. The recent
advance in radio frequency (RF) enabled wireless energy transfer (WET)
technology provides an attractive solution named wireless powered communication
(WPC), where the wireless devices are powered by dedicated wireless power
transmitters to provide continuous and stable microwave energy over the air. As
a key enabling technology for truly perpetual communications, WPC opens up the
potential to build a network with larger throughput, higher robustness, and
increased flexibility compared to its battery-powered counterpart. However, the
combination of wireless energy and information transmissions also raises many
new research problems and implementation issues to be addressed. In this
article, we provide an overview of state-of-the-art RF-enabled WET technologies
and their applications to wireless communications, with highlights on the key
design challenges, solutions, and opportunities ahead.
