# HCLE: Hybrid Clustering Approach for Extending WBAN Lifetime
## 5 Simulation Results and Analysis
### Node Deployment
In the stability period experiment, we focus on the duration from network initiation until the first node's depletion for our proposed protocol (HCEL), along with the SIMPLE and ERRS protocols. From Figure 8, our proposed protocol achieves a stability period of 23% of the total operational duration, slightly surpassing both the ERRS protocol at 21% and the SIMPLE protocol at 20%. These results highlight the effectiveness of our proposed protocol in providing a longer stability period, indicating an extension in the lifetimes of nodes beyond the first node's depletion. The next experiment, shown in Figures 9-11, evaluates the network throughput based on the number of packets successfully received at the sink, the packet delivery ratio (PDR), and the number of dropped packets. To demonstrate the superior performance of our proposed routing protocol (HCEL), we compared the results with both the SIMPLE and ERRS protocols, aiming to establish its maximum throughput advantage. Figure 9 depicts the number of packets successfully delivered to the sink node in different rounds. When there are no dead nodes in all protocols (i.e., from round 0 until round 6383), the sink node receives the same number of packets sent. However, as nodes in the network become inactive or die, the number of received packets at the sink decreases. The delivery of packets to the sink depends on the number of active or alive nodes in the network. Therefore, more alive nodes lead to more data packets to the sink, ultimately maximizing network throughput. Due to the extended lifetimes of sensor nodes in our protocol (HCEL), the number of packets received at the sink is larger than that of the SIMPLE and ERRS protocols. The gap between the HCEL and SIMPLE protocols increases as the number of rounds increases. This occurs because the SIMPLE protocol quickly loses its nodes after the first node's depletion, causing a decrease in the number of received packets at the sink. However, the difference between the HCEL and ERRS is less pronounced due to the extended network lifetime observed in the ERRS protocol. Figure 8: Comparing the stability period among the HCEL, SIMPLE, and ERRS protocols. Figure 10: Analysis of packet delivery ratio (PDR). Figure 9: Analysis of total number of packets successfully received at the sink. Figure 10 shows the packet delivery ratio (PDR) across various rounds. PDR represents the ratio of packets successfully delivered to the sink to the total number of transmitted packets. As our protocol (HCEL) successfully delivers a larger number of packets to the sink, it exhibits higher throughput regarding PDR compared to both the SIMPLE and ERRS protocols. The superiority of our protocol and ERRS protocol can be attributed to its longer stability period resulting from uniform load distribution and increased lifetime of sensor nodes. However, our protocol's performance surpasses that of the ERRS protocol, due to its consideration of the RSSI between the node and sink during parent node selection. When \(PDR=1\), all packets were received successfully to the sink. However, as \(PDR\) decreases, the number of packets dropped increases. Figure 11 illustrates that the number of dropped packets in the HCEL is lower than in the ERRS and SIMPLE protocols. This is due to the longer stability period of our protocol and to the consideration of different parameters when selecting the parent node. In particular, during the stability period, when all nodes are alive, no packets are dropped. The increase in the number of dead nodes and the speed of depletion of nodes influence the total number of packets dropped in different rounds. We measure the average residual energy of 10 nodes across different rounds in our next experiment, shown in Figure 12. Since the initial energy of each node is 4 joules, the average energy in round 0 is 4 joules. The simulation runs until all deployed sensor nodes exhaust their energy (i.e., \(\text{RE}=0\)). Figure 12 depicts the decrease in the residual energy of all deployed nodes as the rounds progress.