  Radio frequency (RF) energy transfer and harvesting has been intensively
studied recently as a promising approach to significantly extend the lifetime
of energy-constrained wireless networks. This technique has a great potential
to provide relatively stable and continuous RF energy to devices wirelessly; it
thus opened a new research paradigm, termed wireless-powered communication
(WPC), which has raised many new research opportunities with wide applications.
Among these, the design and analysis of cooperative schemes towards efficient
WPC have attracted tremendous research interests nowadays. This article
provides an overview of various cooperative strategies for WPC, with particular
emphasis on relaying protocols for wireless-powered cooperative communications,
cooperative spectrum sharing schemes for cognitive wireless-powered networks,
and cooperative jamming strategies towards wireless-powered secure
communications. We also identify several interesting research directions in
this area before concluding this article.
