Adaptive Power and Time Usage Energy Harvesting in Cognitive Two-Way Relay Networks

In this paper, an energy harvesting cognitive network with two-way overlay relaying is discussed, whose secondary users harvest the radio frequency energy from ambient primary information-bearing signals while obtain the spectrum sharing opportunities by relaying those signals. In addition, an adaptive power and time usage (APTUS) energy harvesting relay protocol is proposed as a flexible method that absorbs the essence and discards the dross of the existing schemes for the comprehensive applications. The outage probabilities of primary and secondary users with the APTUS protocol are also derived, and then verified by computer simulations under Nakagami-m frequency-selective fading channels.