Wireless Energy Harvesting Cognitive Radio Network under Finite-Capacity Battery for Nakagami-m Fading

We present a radio frequency (RF) based energy harvesting(EH) cognitive radio network(CRN) with finite-capacity battery at the secondary source(SS). All channels in the network undergo Nakagami-m fading. The secondary network’s(SN) performance is analysed using outage probability and throughput. To obtain a simplified analytical model, we derive the expressions for the upper bound of the outage probability and the lower bound for the throughput of the SN. The analytical expressions for the PDF and CDF of harvested energy of the SN are also derived. The impact of finite battery constraint on the performance of the SN is investigated and analytical expressions for outage probability and throughput are derived. Results show that for an optimal battery capacity, the performance of the SN is identical to that of the infinite-capacity battery assisted CRN. The paper also presents a method to obtain the optimal battery capacity of the CRN under Nakagami-m fading. All analytical results are verified against Monte-Carlo simulations in MATLAB.