Relay Selection in Massive MIMO Wireless Energy Harvesting Cognitive Network

The present work investigates an energy harvesting (EH)-based cognitive massive multiple-input multiple-output (MIMO) and multi-relay assisted network with underlay spectrum sharing. This study considers a secondary network which is allowed to opportunistically access the licensed spectrum band of the primary network, as long as the intra-cell interference imposed on the primary base station due to concurrent secondary network transmissions, does not exceed a pre-defined interference temperature. To this end, analytical expressions of the signal-to-interference-plus-noise (SINR) ratio and the asymptotic achievable sum rate are obtained. Capitalizing on the offered results, the trade-off between the achievable sum rate of the network and the harvested energy on the back of relay selection, is quantified. Monte Carlo simulations are provided to demonstrate the correctness of the proposed mathematical derivations.