Performance Analysis of a Nonlinear Energy-Harvesting Cooperative Spectrum-Sharing Network With Statistical Channel Knowledge

This paper investigates the performance of an energy-harvesting cooperative spectrum-sharing radio network. The proposed system model includes a pair of primary nodes and a relay that harvests energy from a multi-antenna power beacon, which also operates as a gateway for the relay. The energy beamforming design at the power beacon is based only on statistical channel state information. A realistic nonlinear rectenna model is adopted at the relay to capture both sensitivity and saturation effects, as well as capacitor charging dynamics. Analytical expressions are derived for the outage probabilities of the primary and secondary communication links under Rician fading, and asymptotic analyses are presented for both high- and low-signal-to-noise ratio regimes. The results reveal the presence of outage floors due to energy saturation, as well as reliability trade-offs governed by the energy allocation factor at the relay, nodes distance, and array size. The study provides useful design insights for energy-efficient spectrum-sharing IoT systems envisioned for next generation communication systems.