Outage probability of multi-aperture and multi-antenna wireless-powered relaying assisted FSO-RF systems with a nonlinear energy harvester

We consider the outage performance of a mixed free-space optical-radio frequency (FSO-RF) communication system, which consists of a source (S), a relay (R), a destination (D), and a power beacon (PB). In particular, S communicates with D through a multi-aperture and multi-antenna decode-and-forward (DF) relay, which is assumed to harvest energy from the PB under a nonlinear energy harvesting mode. Considering an equal gain combining scheme and a transmit antennas selection scheme, the exact expressions of probability density function (PDF) and cumulative distribution function (CDF) for instantaneous signal-to-noise ratio are first obtained, and then based on those PDF and CDF expressions, the analytical and asymptotic expressions for outage probability are derived. Finally, Monte Carlo simulation results are used to verify the accuracy of the derived analytical expressions.