Performance Analysis of Multihop Cognitive WPCNs with Imperfect CSI

This paper studies the performance of multi-hop cognitive wireless powered communication networks (WPCNs), where secondary nodes can harvest energy from multiple dedicated power beacons and access spectrum of primary receivers (PRs) to support data transmission. Specifically, we consider a practical scenario of cognitive WPCNs, where the channel state information (CSI) of interference links is assumed to be imperfect. To improve the network performance, we propose dual-hop scheduling scheme (DHS) for multi-hop network, where two best relays in two consecutive clusters are selected for data transmission. We then analyze the performance of the proposed scheme in terms of outage probability and outage floor. Numerical results show that DHS scheme outperforms random scheduling scheme, arising as an efficient scheme for multi-hop transmission. Furthermore, the effects of the number of hops, number of power beacons, and time switching ratio on multi-hop cognitive WPCNs are evaluated and discussed.