Energyefficient resource allocation in wireless powered CCRNs with simultaneous wireless information and power transfer Abstract   In this paper, we study the optimal energy efficiency resource allocation for simultaneous wireless information and power transfer (SWIPT) in cooperative cognitive radio networks (CCRNs). The optimal design attempts to deploy each secondary receiver (SR) to harvest the energy and to use the signal received from the secondary transmitter (ST) to decode information. For the information transmission, a traditional multiple access scheme, namely, time division multiple access (TDMA) is addressed. For the TDMAbased information transmission, the users are scheduled in nonoverlapping time slots to decode information. To tackle the design with the above scenarios, an optimization problem is formulated to maximize the energy efficiency of the secondary system constrained with the uncertainty of channel state information (CSI). To solve this nonconvex problem, nonlinear fractional programming is utilized to transform the objective function into a subtractive form. The nonlinear fractional programming is also used to decompose the problem into two convex subproblems, and the probability constraints of signal to interference plus noise ratio (SINR) are converted into the deterministic ones using integral transformation. A joint optimal time and power allocation (JOTPA) iterative algorithm is proposed to determine the optimum of original nonconvex problem. Simulation results have verified the effectiveness of the proposed resource allocation algorithm.

NontimeSharing FullDuplex SWIPT Relay System with Energy Access Point Utilizing the idle wireless devices with energy as an additional energy access point (EAP) to supplement energy for the relay, a nontimesharing fullduplex amplification and forwarding (AF) relay system with energy access points based on radio frequency (RF) signals in wireless networks is proposed. Using AF protocol to cooperative transmit information and simultaneous wireless information and power transfer (SWIPT) technology to realize information and energy synchronous transmission in the energyconstrained relay system. The relay can eliminate the selfinterference signal through selfenergy recycling in the loop channel, and adopts power splitting scheme for information decoding and energy harvest for RF signals. Moreover, due to the nontimesharing transmission characteristics, information transmission, energy harvest and cooperative transmission are completed synchronously in a time block. Taking maximize system throughput as optimization target, jointly optimizing the relay transmit power, the relay transmit beamforming vector and the power splitting ratio, and the system transforms the original multivariate nonconvex problem into a semidefinite programming problem by using quadratic optimization, variable reduction methods and Lagrange method. Simulation experiments show that under the condition that the total energy harvested is fixed, the operation rate of the system can be promoted effectively by increasing the energy harvested from EAP. And the selfenergy recycling of the relay can promote the throughput gain of the system. The experimental results also verify that our proposal the system based on applying nontimesharing transmission protocol and SWIPT technology has more significant gains in improving system performance than HDSWIPT and FDnoSWIPT relay systems.