Outage Analysis of Energy-Harvesting-Based Relay-Assisted Random Underlay Cognitive Radio Networks With Multihop Primary Transmissions

This article exploits the recent advances in wireless energy harvesting to develop a framework for the outage probability of energy harvesting underlay cognitive radio networks. In this model, N-hop primary users are equipped with constant energy source while secondary users (SUs) harvest energy from the transmissions of primary devices. The transmit power of secondary users is regulated to ensure that it does not violate the target end-to-end outage probability constraint of the N-hop primary network. Potential relays that have harvested sufficient energy are eligible to relay data for other SUs within the network. Using this model, we reveal the impacts of the number of primary hops on the relay selection region and harvested energy. An expression for the total outage probability that encapsulates the impact of N primary hops is also derived. Moreover, the effects of other relevant parameters on the outage probability are shown in detail.