Outage Analysis of Wireless-Powered Relaying MIMO Systems with Non-Linear Energy Harvesters and Imperfect CSI

In this paper, we investigate a wireless-powered dual-hop relaying multiple-input multiple-output system, which consists of a multi-antenna source (S) node, a multi-antenna destination (D) node, and N(N > 1) single-antenna wireless-powered relaying nodes. At each relay, a power splitting receiver is applied to process the received signal for information decoding and energy harvesting simultaneously, and a decode-and-forward scheme is adopted to forward the processed information. Furthermore, the energy harvester at each relay is assumed to be non-linear with a saturation threshold to limit the power level of the energy. Assuming imperfect channel state information is available both at S and D, outage performance is investigated when S adopts transmit antenna selection in the presence of feedback delay and D performs maximal ratio combining technique to deal with the multiple copies of signals with channel estimation errors. Taking into account a Kth best relay selection criterion, which results in the Kth best performance in terms of outage probability for the source-relay-destination link, an analytical expression for OP is derived. Monte Carlo simulation results are presented to verify the accuracy of the derived analytical model.