## 5 Numerical Results
Figure 2: Secrecy outage probability of MRC/MRT-SC scheme for different number \(N_{R}\), \(N_{B}\) and \(Q\). Figure 5 shows the SOP versus \(P_{t}/\sigma^{2}\) of the two schemes when \(\overline{\gamma}_{I}=10\) dB, \(\overline{\gamma}_{Bj}/\overline{\gamma}_{Ej}=1\), \(N_{R}=2,N_{B}=4\) and \(N_{R}=3,N_{B}=5\). The asymptotic expressions curves of SOP are achieved from (53) and (56) under the \(\overline{\gamma}_{Bj}\rightarrow\infty\) and \(\overline{\gamma}_{Ej}\rightarrow\infty\), respectively. The analytical results shows that the MRC-ZFB/MRT-SC-ZFB scheme has better performance than MRC/MRT-SC scheme under different \(N_{R}\) and \(N_{B}\). It is noted that, for _fixed_\(\overline{\gamma}_{Bj}/\overline{\gamma}_{Ej}\), increasing \(N_{R}\) and \(N_{B}\) lead to a slight decrease in the values of SOP. Additionally, the MRC-ZFB/MRT-SC-ZFB scheme achieves better performance than the MRC/MRT-SC scheme at the low \(P_{t}/\sigma^{2}\), while the same holds at the high \(P_{t}/\sigma^{2}\). Therefore, the MRC-ZFB/MRT-SC-ZFB scheme improves the transmission performance of wireless communication under Scenario II. Figure 6 shows the SOP of two schemes for different number of \(N_{R}\) and _fixed_\(N_{B}\) varies with \(Q=20\) dB and \(\overline{\gamma}_{I}=10\) dB. As the Relay is equipped with more antennas, the SOP steadily decreases. It can be seen that the MRC-ZFB/MRT-SC-ZFB scheme always outperforms the MRC/MRT-SC scheme, and MRC/MRT-SC with HD operation scheme has a higher SOP under the same conditions. In particular, the MRC-ZFB/MRT-SC-ZFB scheme has a greater influence on the secrecy performance of the system than the MRC/MRT-SC scheme from the perspective of the value of \(N_{R}\). The reason is that the MRC-ZFB/MRT-SC-ZFB scheme enhances system secrecy performance based on FD operation at Bob. Thus, it also verifies the exact validity and the rationality of the closed-form expression of our proposed schemes. It is found that the more \(N_{R}\), the better the system performance, and the secrecy  
Figure 4: Exact and asymptotic secrecy outage probability for the MRC/MRT-SC and MRC-ZFB/MRT-SC-ZFB schemes under Scenario I when \(\overline{\gamma}_{E}=10\) dB, \(\overline{\gamma}_{I}=10\) dB and different values \(N_{R}\) and \(N_{B}\). Figure 5: Exact and asymptotic secrecy outage probabilities for the MRC/MRT-SC and MRC-ZFB/MRT-SC-ZFB schemes under Scenario II when \(\overline{\gamma}_{I}=10\) dB and different values \(N_{R}\) and \(N_{B}\). performance of the proposed MRC-ZFB/MRT-SC-ZFB scheme with FD operation is mainly affected by the secrecy coding gain. Figure 7 shows the secrecy outage probability vs \(\alpha_{1}=\lambda_{AR}/\lambda_{AE}\), and \(\alpha_{2}=\lambda_{RB}/\lambda_{RE}=\left(\varepsilon/\eta\right)\alpha_{1}\). \(Q=20\) dB, \(\overline{\gamma}_{J}=10\) dB, \(N_{R}=2\) and \(N_{B}=6\) are set in two figures. In the first figure, when we set SNR = 20 dB, the simulation results demonstrate that when \(\alpha_{1}\) is relative low, the SOP of two different schemes decreases when \(\alpha_{1}\) increases. The MRC-ZFB/MRT-SC-ZFB of our proposed scheme outperforms MRC/MRT-SC scheme. The main reason is that the main channel is similar with the eavesdropper's channel. However, when \(\alpha_{1}\) is over 20, the eavesdropper's eavesdropping ability is relative weak and the noise power is almost zero, so there is no eavesdropping and interference object for MRC-ZFB/MRT-SC-ZFB scheme. Therefore, the two schemes have almost the same effect on system performance.The second figure shows that the SOP of two different schemes decreases when \(\alpha_{1}\) increases. When \(\alpha_{1}=1\) and 10, the SOP of MRC-ZFB/MRT-SC-ZFB scheme have obvious influence than the MRC/MRT-SC scheme in terms of enhancing the secrecy performance of system. Figure 8 plots the ST versus \(R_{S}\) with different values of \(N_{R}\) and \(N_{B}\).