## 6 Performance Evaluation
### Simulation Results Analysis
#### 6.2.3 PDR with FLTEM and without FLTEM of the Network with Dynamic Topology  
With the topology shown in Figure 1, we deploy 40-300 nodes in a 3D area of \(500\;\mathrm{m}\times 500\;\mathrm{m}\times 500\;\mathrm{m}\). We analyze the effect of FLTEM and the number of MNs on PDR and TEC. The proportion of MNs in the network is 0-0.3. Each MN has an arbitrary attack method listed in Section 2. The experimental results are shown in Figures 16-19.  
Figure 16a-e show the effect of the number of MNs on the PDR of the network with or without the FLTEM mechanism when the number of nodes is 40, 100, 160, 220, and 300, respectively. Specifically, the PDRs reach the maximum values when there is no MN in the network. When there are some MNs in the network, the PDRs decrease significantly. Meanwhile, the PDRs decrease with the increasing number of MNs. The more the number of MNs, the smaller the PDR is. It can be seen from Figure 16a-e that when there are MNs in the network, the PDRs with FLTEM are significantly improved and generally greater than those without FLTEM. The experimental results show that the FLTEM greatly improves the packet delivery rate and transmission reliability of the network with dynamic topology.  
Figure 17a-e show the effect of the number of MNs on TEC with or without FLTEM when the number of nodes is 40, 100, 160, 220, and 300, respectively. From Figure 17a-e, it can be seen that TEC reaches the minimum value when there is no MN in the network. As the number of MNs increases, the TEC increases significantly. Moreover, it is also seen from Figure 17a-e that when there are some MNs in the network, the TEC without FLTEM is significantly greater than that with FLTEM. The experimental results show that the FLTEM mechanism can improve energy efficiency.  
Figures 18 and 19 show the effect of the number of nodes on PDR and TEC with FLTEM under the different proportions of MNs.  
From Figure 18, we can see that no matter whether there are MNs in the network, the PDR increases with the number of nodes. Generally speaking, the PDR of the network  
Figure 15: Effect of the number of MNs on PDR when the number of nodes is 9 and topology is fixed.  
without MNs is greater than the PDR of the network with MNs. The PDR increases as the number of MNs increases, and the PDR of the network with a large proportion of MNs is greater than that of the network with a small proportion of MNs.  
Figure 16: The effect of the number of MNs on PDR with or without FLTEM. (**a**) The total number of nodes is 40. (**b**) The total number of nodes is 100. (**c**) The total number of nodes is 160. (**d**) The total number of nodes is 220. (**e**) The total number of nodes is 300.  
Figure 17: The effect of the number of MNs on TEC with or without FLTEM. (**a**) The total number of nodes is 40. (**b**) The total number of nodes is 100. (**c**) The total number of nodes is 160. (**d**) The total number of nodes is 220. (**e**) The total number of nodes is 300.  
From Figure 19, we can see that no matter whether there are MNs in the network, the TEC increases with the number of nodes. The TEC of the network with MNs is always greater than that of the network without MNs. Moreover, the TEC increases with the proportion of MNs in the network. This is because the number of HELLO packets flooded in the network increases with the number of nodes executing the HELLO packet flooding attack in Section 2, so the TEC of the network increases.  
As shown in Figures 16-19, the performance of the network in terms of PDR and energy efficiency significantly drops when there are some MNs in the network, which is unfavorable for UANs. Fortunately, the experimental results show that the performance of the network in terms of the PDR and energy efficiency is significantly improved after the FLTEM mechanism is introduced.  
The above results show that both the trust mechanism FLTEM and the routing protocol TAFLRLR proposed in this paper can improve the PDR and reduce the TEC of the network.