Performance analysis of energy harvesting relay systems under unreliable backhaul connections.

In this study, the performance of energy harvesting systems in the presence of unreliable backhaul links is investigated over independent but not necessarily identically distributed Nakagami-m fading channels. In particular, the energy-constrained relay uses the amount of harvested energy from the best small-cell transmitter based on time switching-based relaying protocol to process for the next hop transmission. The authors derived the closed-form expressions of the outage probability and the effective throughput with two distinct transmission schemes: (i) delay-limited transmission, and (ii) delay-tolerance transmission are attained. In order to assess the impacts of unreliable backhaul links, they thus obtain the asymptotic expression of the outage probability in high signal-to-noise ratio (SNR) regime. The numerical results are conducted to analyse the effects of energy harvesting fraction time, energy efficiency, backhaul reliability, and the fading parameters on the system performance. The authors' results show that under the unreliable backhaul links the outage probability yields the error-floor in the high SNR regime which demonstrates the significant impact of the backhaul unreliability.