Energy Efficient D2D-Assisted Offloading with Wireless Power Transfer

Traffic offloading via device-to-device (D2D) communications has been proposed to improve the network capacity and alleviate the increasing traffic burden on cellular base stations (BSs). However, the success of D2D communications largely relies on the D2D transmitters' (D2D-Txs) willingness of sharing contents (due to the energy consumption for transmission). In this paper, we model and analyze wireless powered D2D-assisted offloading (WPDO) in underlying cellular networks, where the D2D-Tx is allowed to receive power from the nearest BS as well as other interfering BSs, and then D2D-Tx broadcasts the popular contents to nearby users. The average received power at D2D-Tx and the success probability of D2D-Tx transmission are derived. Furthermore, based on the proposed model, we maximize the network energy efficiency while guaranteeing users' required data rates. Our results confirm that the maximum energy efficiency of the WPDO network can be achieved by jointly optimizing the fraction of time for wireless power transfer and the offloading range of D2D-Tx.