Time Splitting Concurrent Transmission Framework and Resource Allocation in Wireless Powered Communication Networks

This paper studies the joint time and power allocation in wireless powered communication networks. Unlike the conventional interference-free model in the time-divisionmultiple-access harvest-then-transmit framework, we propose a novel transmission framework that allows user equipments (UEs) to send data information concurrently in a time splitting manner, which causes mutual interference among UEs. We investigate the system feasibility for the proposed model with both the time and energy constraints. For time feasibility, we investigate the sum of time resource with given data demand and harvest time. For energy feasibility, we focus on the ratio of transmission energy and harvested energy when the data demand and the transmission time is fixed. As an exemplary application of the proposed model, we investigate the minimum throughput maximization problem, which aims at achieving high data rates but also ensures fairness among UEs. Furthermore, we derive the optimal time allocation for information transmission and energy harvesting, and derive a local optimal solution that satisfies the KKT conditions for the transmit power of UEs to the nonconvex and NP-hard sum rate problem. Numerical results are presented to illustrate the theoretical findings and to show the advantage of our proposed schemes compared to previous protocols.