Time domain spectrum sharing with wireless power transfer in cognitive radio network

The spectrum sharing is able to meet the increasing data transmission requirements over the limited spectrum bands, while the energy harvesting is a promising technique to make the network sustainable by self-recharging the terminals. For the cognitive radio network with one primary link and one secondary link, we propose a time-domain spectrum sharing scheme based on the wireless energy transfer (WET). The secondary transmitter (ST) can wirelessly transfer energy along with the primary base station (PB) to the primary user equipment (UE). The UE can forward its primary data to the PB over the uplink using the harvested energy, while the ST is allowed to access the spectrum and transmit its own data for a time. The main idea is that the secondary system supplies energy to the primary system and acquires the spectrum for the secondary data transmission. Considering the dependence of the energy and data transfer, we analyze the throughput of both systems under the peak power constraint. The time allocations are determined by maximizing the throughput of secondary system while guaranteeing the throughput requirement of primary system. Simulation results are provided to validate our theoretical analysis and the numerical results reveal the impacts of various parameter configurations to the system performance.