  In this paper, we investigate the impact of fading channel correlation on the
performance of dual-hop decode-and-forward (DF) simultaneous wireless
information and power transfer (SWIPT) relay networks. More specifically, by
considering the power splitting-based relaying (PSR) protocol for the energy
harvesting (EH) process, we quantify the effect of positive and negative
dependency between the source-to-relay (SR) and relay-to-destination (RD) links
on key performance metrics such as ergodic capacity and outage probability. To
this end, we first represent general formulations for the cumulative
distribution function (CDF) of the product of two arbitrary random variables,
exploiting copula theory. This is used to derive the closed-form expressions of
the ergodic capacity and outage probability in a SWIPT relay network under
correlated Nakagami-m fading channels. Monte-Carlo (MC) simulation results are
provided throughout to validate the correctness of the developed analytical
results, showing that the system performance significantly improves under
positive dependence in the SR-RD links, compared to the case of negative
dependence and independent links. Results further demonstrate that the
efficiency of the ergodic capacity and outage probability ameliorates as the
fading severity reduces for the PSR protocol.
