SWIPT-Enabled Multi-User Cooperative Communication with Nonlinear Energy Harvesting

In this study, we investigate a multi-user cooperative communication network enabled by simultaneous wireless information and power transfer (SWIPT) based on a nonlinear energy harvesting model. Multiple users act as relays and operate under a power splitting (PS) protocol to assist the data broadcasting from the source node. We provide a system design aiming at minimizing the transmit power via jointly determining the multi-relay selection and PS ratio, while guaranteeing all the users successfully decoding the packet. The nonlinear EH model provides more accurate and realistic results compared with the linear one, but makes the whole problem much more challenging due to the complex implicit function between the charged power and the received power. To address the above difficulty, we characterize the convex components in the problem, and provide an iterative solution based on an efficient algorithm by applying successive convex approximation to the nonconvex components of the problem. Finally, via simulations we validate our analytical model and evaluate the system performance.