# Outage Performance of Wireless Powered Decode-and-Forward Relaying Networks in Rician Fading
## 4 Simulation Results
### Simulation Results and Analysis
It is seen from Figure 5 that when \(K\) is fixed, the system outage probability decreases as \(P_{\text{sum}}\) increases. The reason may be that the larger the \(P_{\text{sum}}\) with the constant noise power, the larger the SNR, which leads to the more collected energy, the higher the probability of reaching \(E_{\text{Q}}\), and the smaller the system outage probability. Besides, when \(P_{\text{sum}}\) is fixed and \(K\) is increased, the system outage probability decreases, which means the system outage performance is better. The reason may be that the larger the \(K\), the more direct signals, and the more energy collected by the relay, which led to the higher probability of reaching \(E_{\text{Q}}\), and the lower the system outage probability. In addition, the system outage performance with equal two-hop distance is slightly less than that with unequal two-hop distance. Figure 6 shows system throughput versus \(P_{\text{sum}}\) with different \(K\) under different two-hop distance. It is seen from Figure 6 that when \(P_{\text{sum}}\) is greater than 35 dBm, the throughput increase rate of the system slows down and finally stabilizes at about 0.3 bit/s/Hz. Besides, when \(K\) is fixed, increase \(P_{\text{sum}}\), the throughput of the system also increases until it stabilizes. When \(P_{\text{sum}}\) is fixed, increase \(K\), and the system outage probability decreases. Moreover, when \(P_{\text{sum}}\) is small, the system throughput with equal two-hop distance is slightly higher than that with unequal two-hop distance. When \(P_{\text{sum}}\) is relatively large, the system throughput under the two distance cases is almost the same. Comparing Figure 5, the changing trend of system outage probability and throughput is opposite. Such observations are consistent with the theoretical results in Equation (16). Figure 7 shows system outage probability versus \(P_{\text{sum}}\) with different \(r_{\text{min}}\) under different two-hop distance. From Figure 7, it can be found that when \(r_{\text{min}}\) is fixed, the system outage probability decreases with the increment of \(P_{\text{sum}}\). The reason may be that the greater the value of \(P_{\text{sum}}\), the higher the probability that the energy collected by the relay reaches \(E_{\text{Q}}\), which leads to the better the system outage performance. Besides, when \(P_{\text{sum}}\) is fixed, the system outage probability increases as \(r_{\text{min}}\) increases. In addition, the system outage performance with equal two-hop distance is slightly smaller than that with unequal two-hop distance. Figure 4: Throughput versus the time assignment factor. Figure 5: Outage probability versus Rice factor. Figure 6: Throughput versus Rice factor. with unequal two-hop distance. When \(P_{\text{sum}}\) is relatively large, the throughput difference between the two distance cases is small. Comparing Figure 9, it can be seen that the system outage probability is opposite to the trend of throughput, and the consistent conclusion can also be drawn according to the theoretical result in Equation (16). Figure 8: Throughput versus transmission rate. Figure 9: Outage probability versus energy conversion efficiency. Moreover, we also launch some simulations based on the piece-wise non-linear EH model to compare the difference between the linear EH model and the piece-wise non-linear EH model. Specifically, when the received energy is less than the circuit saturation threshold, we simulate it with the linear EH mode and when the received energy is greater than the circuit saturation threshold, the available energy is set to be the circuit saturation power, which is set to 1 W. To distinguish from the previous simulation results, we set the first hop distance as \(d_{1}=3\) m, and the second hop distance as \(d_{2}=6\) m. Figures 11 and 12 shows system outage probability and system throughput versus \(\rho\) with different \(P_{\text{sum}}\) under linear EH model and non-linear EH model.