  This paper proposes and analyzes a new full-duplex (FD) cooperative cognitive
radio network with wireless energy harvesting (EH). We consider that the
secondary receiver is equipped with a FD radio and acts as a FD hybrid access
point (HAP), which aims to collect information from its associated EH secondary
transmitter (ST) and relay the signals. The ST is assumed to be equipped with
an EH unit and a rechargeable battery such that it can harvest and accumulate
energy from radio frequency (RF) signals transmitted by the primary transmitter
(PT) and the HAP. We develop a novel cooperative spectrum sharing (CSS)
protocol for the considered system. In the proposed protocol, thanks to its FD
capability, the HAP can receive the PT's signals and transmit energy-bearing
signals to charge the ST simultaneously, or forward the PT's signals and
receive the ST's signals at the same time. We derive analytical expressions for
the achievable throughput of both primary and secondary links by characterizing
the dynamic charging/discharging behaviors of the ST battery as a finite-state
Markov chain. We present numerical results to validate our theoretical analysis
and demonstrate the merits of the proposed protocol over its non-cooperative
counterpart.
