# W-GUN: Whale Optimization for Energy and Delay-Centric Green Underwater Networks
## 4 Results and Discussion
### Analysis of Results
This can be attributed to the fact that the optimal and stable underwater nodes are considered in the proposed framework, in comparison with the literature majorly relying on the quality of service and location-centric underwater relay nodes. W-GUN utilized underwater characteristics resulting in a considerable energy performance gain. This energy performance gain is further represented in a more understandable way in Figure 8, where percentage gain and energy consumption observations are shown in close relation for better  
Figure 7: Energy consumption versus the number of underwater nodes. clarity and understanding. This verifies the results presented in Table 3 and Figure 7. Therefore, the proposed underwater framework outperforms the state-of-the-art techniques with considerably lower energy consumption. The overall network lifetime as a function of the number of sensor nodes in the underwater network is comparatively investigated in Figure 9, considering the proposed framework and the state-of-the-art techniques. Similar network density in the range of 100-500 sensor nodes is considered for this experiment. It can be easily noticed that the network lifetime is effectively longer for the proposed underwater relay optimization framework than the compared state-of-the-art techniques. It is evident that the optimal selection of underwater relay nodes enhances the communication performance of the overall network in terms of a longer network lifetime. For a durable network lifetime, the underwater communication path should be optimal. The aim of the proposed optimization method is to select the maximal number of underwater communication routes with a minimal number of underwater relay nodes. Therefore, the route consists of the minimum number of underwater relay nodes in our proposed approach. Therefore, the network lifetime is longer considerably compared with existing schemes in the underwater literature. The longer network lifetime-centric performance benefits of the proposed framework are explored in detail in Table 4 in terms of percentage gain compared with the literature. The average performance gain of W-GUN in terms of network lifetime percentage can be notes as 12%, 32%, and 46% for literature including ES-VBF, HH-VBF and, VBVA respectively. The performance benefits can be reasoned to the fact that the natural underwater characteristics are not considered in the literature, which rather majorly relied on the quality of service and location information of underwater relay nodes. However, the proposed framework has utilized underwater characteristics, resulting in considerable performance gain and a longer network lifetime. This network lifetime performance gain is further represented in a more readable way in Figure 10. Here, the percentage gain and network lifetime observations  
Figure 8: Detailed percentage-centric performance gain of W-GUN focusing energy consumption. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multicolumn{5}{c}{**Energy Consumption (J) Comparison with a Varying Number**} & \multicolumn{5}{c}{**\% Improvement of W-GUN Compared with Existing Schemes**} \\ \multicolumn{5}{c}{of Nodes**} & \multicolumn{5}{c}{**\% Gain of W-GUN**} & \multicolumn{5}{c}{**\% Gain of W-GUN**} & \% Gain of W-GUN \\ \multicolumn{5}{c}{} \\ \multirow{2}{*}{**Nodes**} & \multirow{2}{*}{**VBF**} & \multirow{2}{*}{**HH-VBF**} & \multirow{2}{*}{**VBVA**} & \multirow{2}{*}{**ES-VBF**} & \multirow{2}{*}{**W-GUN**} & **\% Gain of W-GUN**} & \multirow{2}{*}{\% Gain of W-GUN**} \\  & & & & & & **Compared with** & **Compared with** \\  & & & & & **ES-VBF** & & **VBVA** & **HH-VBF** \\ \hline
100 & 557 & 758 & 1050 & 466 & 229 & 51 & 78 & 70 \\
200 & 768 & 1048 & 1358 & 568 & 398 & 30 & 71 & 62 \\
300 & 2778 & 3168 & 3778 & 2449 & 1880 & 23 & 50 & 41 \\
400 & 5880 & 6260 & 6660 & 5300 & 4449 & 16 & 33 & 29 \\
500 & 6460 & 7140 & 7400 & 5800 & 5018 & 13 & 32 & 30 \\  & & & & & 27 & 53 & 46 \\ \hline \hline \end{tabular}
\end{table}