Exact outage analysis of a decode-and-forward cooperative communication network with Nth best energy harvesting relay selection

In this paper, a decode-and-forward cooperative communication network (DFCCN) with energy harvesting relays is investigated in which a selected best relay with the Nth channel gain harvests energy from received radio frequency signals and then consumes the harvested energy by forwarding the recoded signals to a destination. Based on the studied energy harvesting receivers, two operation protocols are proposed: (1) power splitting relays in DFCCN (PSDFCCN protocol) and (2) time switching relays in DFCCN (TSDFCCN protocol). The system performances of the proposed protocols are evaluated based on the exact outage probabilities and compared to that of the direct transmission protocol. The theoretical results are confirmed by Monte Carlo simulations. It is found that (1) the system performances of the proposed PSDFCCN and TSDFCCN protocols are improved when the number of energy harvesting relays increases and when the parameter N is small; (2) the proposed PSDFCCN and TSDFCCN protocols with a small N value outperforms the direct transmission protocol; (3) the target signal-to-noise Ratio (SNR), the location of cooperative relays, and the energy harvesting parameters, e.g., the power splitting ratio, energy harvesting time, and energy conversion efficiency, have significant impacts on the system performance; and (4) the theoretical results agree well with the simulations.