Current wireless and cellular networks are destined to undergo a significant change in the transition to the next generation of network technology. The so called wireless powered communication network (WPCN) has been recently emerging as a promising candidate for achieving the target performance of future networks. According to this paradigm, nodes in a WPCN can be equipped with hardware capable of harvesting energy from wireless signals, that is, their battery can be ubiquitously replenished without physical connections. Recent technological advances in the field of wireless power harvesting and transfer are providing strong evidence of the feasibility of this vision, especially for low-power devices. The future deployment of WPCN is more and more concretely foreseen. The aim of this article is therefore to provide a comprehensive review of the basics and backgrounds of WPCN, current major developments, and open research issues. In particular, we first give an overview of WPCN and its structure. We then present three major advanced approaches whose adoption could increase the performance of future WPCN: backscatter communications with energy harvesting; duty-cycle based energy management; and transceiver design for self-sustainable communications. We discuss implementation perspectives and tools for WPCN. Finally, we outline open research problems for WPCN.