Sum of Average Throughput Maximization in Energy Harvesting Cooperative Wireless Communication

This paper studies a cooperative wireless powered communication network system. The communication between uplink users and hybrid access point is supported by energy harvesting relays. In contrast to the exiting works, we assume that the uplink users also harvest energy from the energy signal transmitted by the hybrid access point. Furthermore, it is assumed that the relays employ decode and forward relaying protocol for relaying the users information to the access point. We propose an optimization problem whose aim is to maximize the average sum throughput of the system. It is proved that the proposed optimization problem is convex. Karush Kuhn Tucker (KKT) conditions are used to find the optimal time allocations for the energy signal transmission and information signal transmissions. The proposed scheme for finding the optimal time allocation does not require instantaneous channel state information therefore significant reduction in the feedback information can be achieved by using the proposed scheme. The simulation results show that the proposed time allocation can significantly improve the performance of the system.