Secrecy Outage Analysis of Energy Harvesting Enabled Two User Cooperative NOMA

Abstract

In this paper, we evaluate the secrecy outage probability (SOP) of two user cooperative non-orthogonal multiple access (C-NOMA) network in the presence of a passive eavesdropper (E). The near user $(U_{1})$ harvests energy from the superimposed signal transmitted by source (S). The near user $(U_{1})$ acts as a relay and retransmits the message signal to a far user $(U_{2})$. The E eavesdrops the signal for $U_{1}$ and $U_{2}$ transmitted from $\mathbf{S}$ and eavesdorp the signal of $U_{2}$ relayed from $U_{1}$. An MRC is applied at E on two copies of signals obtained for $U_{2}$. An analytical framework for evaluating SOP is presented. We obtain an analytical expression for SOP of $U_{1}$, while an analytical expression of SOP of $U_{2}$ at high SNR approximation is obtained. Impact of several netwrok parameters such as target secrecy rate, energy harvesting parameters on SOP is indicated. Our analytical results are supported by monte-carlo simulation carried out in MATLAB.