# An Eccentricity Based Data Routing Protocol with Uniform Node Distribution in 3D WSN
## 4 Performance Evaluation
### Simulation Results
#### 4.2.6 Impact of \(T_{\rm E}\) on Network Lifetime  
The factor \(\alpha\) to define \(T_{\rm E}\) plays a significant role in network lifetime of EDR. It must be considered in such a way that whenever all the member nodes in a subspace are below \(T_{\rm E}\), they can continue with the rest of periodic RC nodes election process in the subspaces. Otherwise, the overall network lifetime may decrease due to the lack of insufficient residual energy of the nodes after participating in the RC nodes election in their quasi-static periods.  
We examine the impact of \(T_{\rm E}\) on the network lifetime of EDR for different values of \(\alpha\) in both of the node distributions. Besides the network lifetime, we took into consideration the number of \(D\_M\)s\(\rm{gs}\) and throughput received at RC nodes and sink, respectively. Figures 9a and 10a show the number of packets received at different RC nodes and sink, accordingly in uniform node distribution. The results show that the number of local packets received at RC nodes and throughput increase with increases in the value of \(\alpha\). It is observed that, as the value of \(\alpha\) increased (\(\alpha>7\)), the number of packets is decreased significantly due to the shorter steady state and network lifetime. Figures 9b and 10b show the packets received in the nonuniform node distribution. It is to be noticed that when \(\alpha\) is greater than a certain  
Figure 8: (**a**) Number of alive nodes in each round (uniform); (**b**) Number of alive nodes in each round (a best case of nonuniform node distribution where \(\alpha=4\) and the nodes are not equally distributed over the network).  
value (i.e., \(\alpha=4\)), the throughput increases, but some of the nodes are being isolated from the sink, resulting in a shorter network lifetime, as shown in Figure 11b:  
Figure 10: _Cont._  
Figure 9: (a) Number of local data packets sent to RC nodes for different \(T_{\text{E}}\) in EDR (uniform); (b) Number of local data packets sent to RC nodes for different \(T_{\text{E}}\) in EDR (nonuniform).  
The steady state as well as the network lifetime of EDR enhances with the increase in the value of \(\alpha\) in uniform compared to nonuniform, as shown in Figure 11a,b, respectively. The distinctive feature of the uniform to notice that when the value of \(\alpha\) is smaller (\(\alpha=2\), \(\alpha=3\)), around 20% of nodes in the distant subspaces are being isolated from the sink due to the early death of the nodes in the nearest subspaces to sink. As the nodes are equally distributed over the network and the quasi-static period is shorter, the periodic RC nodes election period gets longer. Therefore, the nodes dissipate energy more quickly due to the process of RC nodes election in each round. Moreover, the elected RC nodes near the sink participate as the data forwarding nodes for the distant RC nodes in the network and consume more energy compared to the distant RC nodes which results in the nearest nodes to the sink to die more quickly. On the other hand, when the value of \(\alpha\) gets larger, the quasi-static period is getting longer; thus, the periodic RC nodes election period is getting shorter. The consequence is that the nodes save energy due to a minimized number of RC nodes election processes throughout the network lifetime. As a result, the steady state and the network lifetime are prolonged.  
Figure 11: _Cont._  
Figure 10: **(a)** Number of data packets sent to the sink for different \(T_{\mathrm{E}}\) in EDR (uniform); **(b)** Number of data packets sent to the sink for different \(T_{\mathrm{E}}\) in EDR (nonuniform).