Wireless Energy Transfer Enabled D2D in Underlaying Cellular Networks

Wireless powered device-to-device (D2D) communications can prolong the lifetime of energy constrained D2D transmitters. This paper proposes an analytical model for D2D communications powered by both ambient radio frequency (RF) signals from base stations (BSs) and power beacons (PBs) in a multichannel downlink cellular network to enhance harvested energy at D2D transmitters without changing the original cellular networks. With fixed transmit powers of D2D transmitters, we derive a probability for D2D transmitters to harvest enough energy for D2D communications based on stochastic geometry. We investigate the profit gained by a cellular system with RF wireless energy transfer enabled D2D (WET-D2D), where the profit is defined as the difference between the revenue earned from downlink data transmission from BSs and D2D communications and the energy cost for BSs and PBs. Numerical results verify that a maximum profit of a cellular system with WET-D2D is achieved with a well-designed PB and proper transmit powers at D2D transmitters.