## 5 Performance Analysis and Simulation
### Comparison of the Performance Simulation
#### 5.3.2 Comparison of Communication Overhead  
**Experiment 6:** Comparison of communication overhead between NRSPS and other three schemes  
In Experiment 6, we compare the communication overheads of our proposed NRSPS scheme with the shortest path algorithm, EPUSBRF and RPBMP. Since each node consumes the same communication overhead when forwarding packets, the number of nodes through which each packet passes is used as the communication overhead of the routing phase. The total communication overhead is the sum of the communication overheads consumed in the PN phase determination phase and the routing phase. We perform Experiment 6 repeatedly for 100 times and compare its communication overhead with the other three schemes. The simulation results are shown in Figure 15.  
It can be seen from Figure 15 that the total communication overhead of our proposed NRSPS scheme is only slightly higher than that of the shortest path algorithm. While compared with EPUSBRF and RPBMP, the total communication overhead of our proposed NRSPS is reduced by 95% and 88%, respectively. The higher communication overhead of EPUSBRF is due to the high communication overhead in the phase of determining PN. In the experiment, \(h\) is set to be 3 in the flooding phase of EPUSBRF, so the communication overhead for determining PN is 8.64 + 8.642 + 8.643 + 3 = 731.26 (see Section 5.2.1 for theoretical analysis). It can be seen that in the phase of determining PN, the SoN performs flooding to determine the PN which causes a large amount of communication overhead. While in this paper, the SN helps the SoN determine the PN, which saves a lot of communication overhead. Figure 14: Comparison of the safety period of RSPS and RDPS with different \(M\). **Experiment 7:** Comparison of communication overhead of our proposed four schemes  
We further compare the communication overheads of our proposed four schemes of NRSPS, NRDPS, RSPS and RDPS. The average communication overhead is obtained by repeating the experiment 100 times, as shown in Figure 16.  
As can be seen from Figure 16, the communication overhead of the RDPS scheme is the largest, and compared with the NRSPS, RSPS and NRDPS, the communication overhead is increased by 53.1 times, 2.39 times, and 7.10 times, respectively. In Figure 16, the communication overhead of NRSPS does not change much. This is because the communication overhead of NRSPS is low, and the change is too small compared with other schemes. The actual change trend of NRSPS is shown in Figure 16. It can also be seen from Figure 16 that the communication overhead of RSPS and RDPS is greatly increased compared with that of NRSPS and NRDPS. This is because the number of nodes through which the packet passes after the PN is changed increases, resulting in an increase in communication overhead. Although changing the PN can improve the security performance of the scheme, it also causes large communication overhead. Figure 16: Comparison of the communication overhead of NRSPS, RSPS, NRDPS and RDPS. Figure 15: Comparison of communication overheads between NRSPS scheme and other three schemes. In summary, the communication overhead of the PN determination phase (Overhead 1 for short), the communication overhead of the routing phase (Overhead 2 for short), the total communication overhead (Total overhead for short), and the total safety period are shown in Table 4.  
In order to more clearly compare the cost performance of each scheme, we refer to the Safety Period/Communication Cost as the SC ratio. The higher the SC ratio is, the better the performance of the scheme is. It can be seen from Table 4 that the performance of RSPS is better than other schemes. Although the other three schemes proposed in this paper have lower communication overhead or higher safety period, the performance is not balanced. The average total safety period of NRSPS and NRDPS is less than 1000, so the SoN may be captured by the attacker.