Coverage Characterization in Wireless Powered Communication Networks with Energy Harvesting

The performance of wireless powered communication networks (WPCNs) with transmitters (TEs) self-sustained by opportunistically harvesting radio-frequency (RF) energy from nearby power beacons (PBs) is investigated. A ``harvest-then-transmit´´ protocol is considered, under which a TE first harvest the wireless energy from its nearest PB and then send information to its associated receiver (RE) with the energy stored in the battery. A variable power transmission mode is proposed that the TE is allowed to transmit as long as its harvested energy is larger than a predefined transmission threshold. The transmission probability of the TEs is derived. The coverage probability with the TEs non-fully charged and fully charged, respectively, are characterized. By using numerical analysis, we study the tradeoff between energy harvesting and data transmission for different system parameters, such as energy harvest-ratio, transmission threshold, and PB density. Simulation results are provided to validate our theoretical analysis.