  This paper analyzes the performance of a cooperative relaying non-orthogonal
multiple access (NOMA) network over Fisher-Snedecor F composite fading
channels. Specifically, one base station (BS) is assumed to communicate with
two receiving mobile users with one acting also as a decode-and-forward (DF)
relay. To highlight the achievable performance gains of the NOMA scheme,
conventional relaying with orthogonal multiple access (OMA) is also analyzed.
For the two systems under consideration, we derive novel exact closed-form
expressions for the ergodic capacity along with the corresponding asymptotic
representations. The derived expressions are then used to assess the influence
of various system parameters, including the fading and shadowing parameters, on
the performance of both the NOMA and OMA systems. Monte-Carlo simulation are
provided throughout to verify the accuracy of our analysis. Results reveal that
the NOMA system can considerably outperform the OMA approach when the power
allocation factor is carefully selected. It is also shown that as the fading
and/or shadowing parameters are increased, the ergodic capacity performance
enhances.
