  With the recent advances in radio frequency (RF) energy harvesting (EH)
technologies, wireless powered cooperative cognitive radio network (CCRN) has
drawn an upsurge of interest for improving the spectrum utilization with
incentive to motivate joint information and energy cooperation between the
primary and secondary systems. Dedicated energy beamforming (EB) is aimed for
remedying the low efficiency of wireless power transfer (WPT), which
nevertheless arouses out-of-band EH phases and thus low cooperation efficiency.
To address this issue, in this paper, we consider a novel RF EH CCRN aided by
full-duplex (FD)-enabled energy access points (EAPs) that can cooperate to
wireless charge the secondary transmitter (ST) while concurrently receiving
primary transmitter (PT)'s signal in the first transmission phase, and to
perform decode-and-forward (DF) relaying in the second transmission phase. We
investigate a weighted sum-rate maximization problem subject to the
transmitting power constraints as well as a total cost constraint using
successive convex approximation (SCA) techniques. A zero-forcing (ZF) based
suboptimal scheme that requires only local CSIs for the EAPs to obtain their
optimum receive beamforming is also derived. Various tradeoffs between the
weighted sum-rate and other system parameters are provided in numerical results
to corroborate the effectiveness of the proposed solutions against the
benchmark ones.
