Resource Allocation for Multiuser Cooperative Overlay Cognitive Radio Networks with RF Energy Harvesting Capability

We address the resource allocation problem for energy- harvesting (EH) based OFDMA cooperative overlay cognitive radio networks with multiple primary users (PUs) and multiple secondary users (SUs), where PUs and SUs cooperate in terms of both information transmission and energy harvesting. Specifically, SU transmitters first apply the power splitting tech- nique to harvest energy from signals radiated by PU transmitters, and then use the harvested energy to transmit their own and PUs'information. We discuss the joint optimization over relay assignment, subcarrier allocation, power splitting ratio selection, and power control under imperfect channel state information (CSI) conditions, with the objective to maximize SUs' total throughput while guaranteeing PUs' quality-of-service (QoS) requirements. In particular, the direct transmission between each PU transmitter and its corresponding primary receiver is taken into account, and then cooperative transmission with SUs is selected dynamically according to network channel conditions. Although the formulated problem is a non-convex problem with integer variables (e.g., relay assignment variables), we still propose a suboptimal distributed algorithm. Finally, we evaluate and verify the performance of our proposed algorithm through numerical analyses.