# DOW-PR DOlphin and Whale Pods Routing Protocol for Underwater Wireless Sensor Networks (UWSNs)
## 7 Conclusions  
A dolphin and whale pods routing protocol (DOW-PR) has been proposed in this paper. There are two versions of the proposed protocols i.e., dolphin pods and the whale pods. Whale pods routing protocol is the further enhancement of the dolphin pods routing. Basically, the proposed scheme enhanced the performance of the metrics simulated in its state-of-the-art counterpart routing protocol i.e., Weighting Depth Forwarding Area Division Depth Based Routing (WDFAD-DBR) protocol. DOW-PR provides a reduction in energy consumption, increasing PDR, and minimizing end-to-end delay. In the proposed scheme, it explores the role of the parameters like potential forwarding nodes number, suppressed nodes numbers and hops count value in designing the holding time equation. Moreover, the values of the above-mentioned parameters have been mapped (SET1, SET2 and SET3) into arbitrary values and that are also tested for simulations. The investigations through simulations showed that dolphin pods routing beats the WDFAD-DBR, on average improving by 31.5% of energy tax, 6% of PDR, and 24.6% of E2 ED. However, certain performance trade-offs have been observed and listed in Table 8. Furthermore, the whale pods routing protocol outperformed the dolphin pod version and therefore improvement is seen in energy tax, PDR and E2 ED.  
In the future, we will investigate the other sets of arbitrary values for mapping the actual values of potential forwarding nodes number, suppressed nodes number and hops count. Other than this, we will deploy a greater number of movable underwater sink nodes.  
**Author Contributions:** [PERSON] and [PERSON] conceived the main ideas presented in this research work, performed the simulations and analyses. [PERSON] contributed extensively in designing and performing the underwater acquisitions. [PERSON], [PERSON] and [PERSON] significantly contributed to critically revise and finalize the research. All authors equally contributed in the paper writing.  
**Funding:** This research was funded by the National Natural Science Foundation of China (No.61671349 and 61301175), in part by the Fundamental Research Funds for the Central Universities (No.GB180205), in part by the International Scientific and Technological Corporation and Exchange Projects in Shaanxi Province (Grant No. 2017 KW-2005).  
**Conflicts of Interest:** The authors declare no conflict of interest.  
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Features** & **Achievements** & **Price to pay** \\ \hline Forwarder selection from SUPs & PDR improvement Figure 12a & End-to-end delay Figure 12c \\ \hline Prioritizing forwarder through Holding time & Energy consumption reduction Figure 12b & \\ Prioritizing forwarder through Holding time & Duplicate packets reduction & Upward packet advancement \\  & Collision avoidance & \\ \hline Embedded Sink & Prolong network lifetime Figure 13c, end-to-end delay reduction Figure 14c, Reliability Figure 14a & Deployment and physical connection maintenance cost \\ \hline Transmission zones & Energy tax reduction Figure 12b & Computationally complex \\ \hline Hop Count Mechanism & APD Improvement Figure 12d & \\ end-to-end delay Figure 12c & Computationally complex \\ \hline \hline \end{tabular}
\end{table}
Table 8: Performance trade-offs.