# An Energy Efficient Routing Approach for IoT Enabled Underwater WSNs in Smart Cities
## 4 Results and Discussion
### Performance Evaluation
#### 4.1.3 U-(ACH)\({}^{2}\) with One Sink at Water Surface and One Underwater
In the proposed study, the challenge we face in each scenario is the harsh and unpredictable behavior underwater. Underwater, acoustic signals can cover more distance as compared to radio waves due to which acoustic signals are preferred. However, the scattering nature of water may affect the efficiency of our network. With respect to the benchmarks, the proposed schemes perform better in almost all the considered scenarios. The purpose of considering 3 different scenarios is to get well informed before the implementation of a scheme. The installation of a scheme can be implemented in any of the three scenarios or maybe the organization has some constraints and wants to deploy sink nodes in a particular fashion then with the help of this study, the organization is able to find the optimal solution for its operation and so on. As it can be seen that for every scenario, the routing protocol performs differently. In scenario-1, the DEEC-(ACH)\({}^{2}\) protocol outperforms for most of the metrics of evaluation and generates promising results. DEEC-(ACH)\({}^{2}\) shows the maximum number of packets are received at BS and less number of nodes died with respect to other routing protocols. However, a trade-off occurs between the maximum number of packets sent to the BS and packet drop ratio. DEEC-(ACH)\({}^{2}\) \begin{table}
\begin{tabular}{l l l l l} \hline \hline
**Protocol** & **Advances Achieved** & **Price to Pay** & **Working Principle** \\ \hline DBR & Minimum end to end delay, maximum throughput & Maximum energy consumption & Multi-hop \\ \hline EEDBR & Minimum end to end delay, maximum throughput & Maximum energy consumption & Multi-hop \\ \hline LEACH-\((ACH)^{2}\) & Average network lifetime & Throughput \& max. energy consumption & Away clustering \\ \hline DEEC-\((ACH)^{2}\) & Enhanced network lifetime, maximum packets send and received, less no. of dead nodes & Costly & Away clustering \\ \hline TEEN-\((ACH)^{2}\) & Extends network lifetime & Throughput & Away clustering \\ \hline SEP-\((ACH)^{2}\) & Extends network lifetime & Costly & Away clustering \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Comparison of Proposed and Existing Protocols. \begin{table}
\begin{tabular}{l l l l l} \hline \hline  & **TEEN-(ACH)\({}^{2}\)** & **DEEC-(ACH)\({}^{2}\)** & **SEP-(ACH)\({}^{2}\)** & **LEACH-(ACH)\({}^{2}\)** \\ \hline No. of dead nodes & high & high & less & high \\ No. of packets sent to BS & min & max & min & min \\ No. of packets dropped & less & high & high & high \\ No. of packets received & min & max & min & min \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Scenario-III: Performance of proposed schemes. is able to send the maximum number of packets to the BS due to which packet drop ratio is also high. In scenario-2, LEACH-(ACH)\({}^{2}\) protocol performs better than all other schemes. Likewise, DEEC-(ACH)\({}^{2}\) in scenario-1, here LEACH-(ACH)\({}^{2}\) protocol acts similarly. LEACH-(ACH)\({}^{2}\) shows the maximum number of packets received at BS and fewer nodes died in scenario-2. However, a tradeoff occurs between the maximum number of packets sent to the BS and packet drop ratio. LEACH-(ACH)\({}^{2}\) is able to send the maximum number of packets to the BS due to which packet drop ratio is also high. In scenario.3, DEEC-(ACH)\({}^{2}\) is able to send the maximum number of packets to BS, and the maximum number of packets are received at BS. For packet drop ratio TEEN-(ACH)\({}^{2}\) performs best while less number of nodes died using SEP-(ACH)\({}^{2}\). From these results, we have concluded that our proposed schemes have generated promising results and perform better than the benchmarks in each scenario.