# Secure Information Transmission with Self Jamming SWIPT
## 3 Numerical Results  
In this section, the BER performance of the legitimate user and eavesdropper in the system model is analyzed by using Monte Carlo simulations. The signal used the 2.4 GHz frequency band, \(T=4\times 10^{-6}\), and it was considered that all the communication nodes including the eavesdroppers were operating in the non-line-of-sight channel condition. The secrecy rate was another performance metric of the legitimate user in the presence of the eavesdropper at various conditions and was analyzed through simulations. In the following simulations, the system adopted the 4-QAM signal with \(K=256\) and \(L=200\), and the IB-DFE receiver was used in \(R\) and \(\xi\) to improve their error rate performance. The channel estimate errors of the \(\mathbf{H}_{E1R}\) and \(\mathbf{H}_{E2R}\) links, i.e., \(\varepsilon_{E1R}\) and \(\varepsilon_{E2R}\), respectively were assumed to be equal, i.e., \(\varepsilon_{E1R}=\varepsilon_{E2R}\), and \(\varepsilon_{E1R}\) was either 0.02 or 0.1. We assumed that, under an exceptionally favorable circumstance, \(\rho_{E1}=\rho_{E2}=0.99\) and 0.98; this allowed \(\xi(b)\) and \(\xi(c)\) to perform better than \(\xi(a)\). In the following figures, the BER performance results by default illustrate the fourth iteration of the IB-DFE decoder unless it is specified as zero-forcing (ZF) decoding. Figure 3 demonstrates the BER performance of \(R(a)\) and \(R(b)\). We see that the BER performance of \(R(a)\) did not vary with the change in \(\beta\), due to the successful channel precoding, which was based on the complete CSI of the EH signals, i.e., jamming signals. Furthermore, the results of \(R(a)\) demonstrated that the performance of IB-DFE receiver and BER improved up to the fourth iteration. In the first iteration, without any feedforward and feedback values, the resultant BER of the first iteration was equal to the ZF decoding. For \(R(b)\), the channel precoding error occurred due to \(\varepsilon_{E1R}\), where \(\varepsilon_{E1R}=0.02\) and 0.1, and the results demonstrated that due to the precoding error at the transmitter, the BER performance of \(R(b)\) was poorer as compared to \(R(a)\). When \(\varepsilon_{E1R}=0.2\), up to \(\beta=4\), the performance of \(R(b)\) was equivalent to that of \(R(a)\), whereas for \(\beta>4\), the performance of \(R(b)\) degraded with the increase in \(\beta\). The precoding error increased proportionally with the increase in \(\varepsilon_{E1R}\), and \(\beta\) acted as a multiplication factor in increasing the precoding error. Figure 4 demonstrates the BER performance of \(\xi\) in all the scenarios with the comparison to BER of \(R\), and \(\xi(a)\) received an incompatible signal for decoding the information. Unlike \(\xi(a)\), with \(\rho_{E1}=\rho_{E2}=0.99\) and \(0.98\), \(\xi(b)\) and \(\xi(c)\) could partially decode the signal, and their performance degraded with the decrease in \(\rho_{E1}\) as the precoding errors increased in turn. Due to high channel correlation between \(\mathbf{H}_{E1\xi}\) and \(\mathbf{H}_{E1R}\) and similarly between \(\mathbf{H}_{E1\xi}\) and \(\mathbf{H}_{E1R}\), the jamming EH signals were partially canceled out in \(\xi(b)\) and \(\xi(c)\), allowing them to perform better than \(\xi(a)\). With \(\epsilon_{E1R}=0.02\), \(\xi(b)\) performed slightly more poorly as compared to \(\xi(c)\). Even though \(\xi(b)\) and \(\xi(c)\) could decode information in the high channel correlation condition, the BER results of \(R\) demonstrated that, by increasing \(\beta\), the jamming signals could degrade the performance of \(\xi\), while \(R\) suffered a negligible loss. Figure 5 demonstrates the impact of the inclusion of \(\beta\sigma_{A}^{2}\) in the IB-DFE receiver, and the results validated the advantage of using (23) over (21) in the iterative loop. \(R_{i}\) had significant SINR gain over \(R(b)\) with the increase in \(\beta\). At \(\beta=10\), \(R_{i}\) had 0.5 dBm SINR gain over \(R(b)\), and when \(\beta>12\), \(R_{i}\) had more than 6 dBm SINR gain over \(R(b)\).