# HCLE: Hybrid Clustering Approach for Extending WBAN Lifetime
## 5 Simulation Results and Analysis
### Node Deployment
After each round of data transmission, our protocol only sends the unique identifier of the respective parent node to two-hop sensor nodes, without requiring the transmission of the cost function to all nodes for parent node selection, as done in the SIMPLE protocol. Furthermore, one-hop sensor nodes in our protocol do not need to send their updated residual energy to the sink for cost function calculation, as required in the SIMPLE protocol. However, in the ERRS protocol, the overhead during the initialization phase is 53,281 bits, which is less than in our HCEL protocol. This discrepancy occurs because nodes in the ERRS protocol transmit only their residual energy to the sink node during initialization, whereas in the HCEL protocol, they transmit both residual energy and RSSI values. This leads to an increase in the number of bits during the initialization phase in the HCEL protocol. Additionally, after each data transmission round in the HCEL protocol, all nodes must send their updated residual and  
Figure 5:3 Analysis of network path loss. RSSI to the sink node to calculate the cost value and then choose the appropriate parent node. Conversely, in the ERRS protocol, nodes only send updated residual energy to select the parent node, resulting in a decrease in communication cost across different rounds compared to our HCEL protocol. It is observable that the SIMPLE protocol generates a smaller number of bits for communication from rounds 7981 to 22,268 compared to the HCEL and ERRS protocols. That is because no two-hop sensor nodes are still alive for any communication. However, when all protocols have the same number of alive nodes, ERRS and our proposed protocol (HCEL) require fewer bits for communication between sensor nodes and the sink, as in the case from rounds 0 to 6383. This reduction in communication cost is attributed to the optimized overhead calculation and efficient exchange mechanisms employed in our proposed protocol. By optimizing these aspects, our protocol reduces communication costs between sensor nodes and the sink compared to the SIMPLE protocol. ETX is calculated, as discussed in Section 3.4.7, to measure the link quality of our proposed protocol (HCEL), as well as the SIMPLE and ERRS protocols in different rounds. In Figure 16, it can be seen that, when all sensor nodes are operational for all protocols, the ETX value stands at 1. This implies that no packets are lost and that every packet is successfully transmitted to the sink. However, as the packet loss between nodes increases, the ETX value also increases. The ETX values in the SIMPLE protocol are larger than those of our proposed protocol (HCEL) and ERRS protocol, especially after round 7300 for HCEL and after round 6425 for ERRS. This indicates that the link quality in the SIMPLE protocol is poorer compared to both the HCEL and ERRS protocols. In general, as the number of rounds increases, the gap in ETX values between our protocol and SIMPLE widens, referring to a larger number of successfully received packets in the HCEL protocol compared to the SIMPLE protocol. However, this gap narrows between the HCEL and ERRS protocols due to the improved network lifetime observed in the ERRS protocol compared to the SIMPLE protocol. Figure 5:4 Analysis of network communication cost.