# Void Avoidance Opportunistic Routing Protocol for Underwater Wireless Sensor Networks
## 4 Simulation Results
### Scenario 2:
#### 4.2.2 Results and Analysis  
**Total Energy consumption:** the total energy consumption of the three protocols is illustrated in Figure 9. As we can see in the three subfigures, the transmission power level and node density have a direct impact on the total energy consumption. That is, increasing either the power level or the node density increases the connectivity between the deployed nodes in the network topology. A higher connectivity means a larger number of nodes participating in the data forwarding procedure, thereby increasing the energy consumed. Moreover, we noted from the figure that, for example, for 100 nodes, the total energy consumption increased by approximately 10 times when we increased the power level from 8.5 W to 35 W, and about 17 times when increased from 8.5 W to 55 W, while, for example, in the topology with a transmission level of 8.5 W, increasing the density of the network from 100 nodes to 310 nodes increases the total energy consumption by only about 7 times. Consequently, the power level has more effect on the EEDOR-VA total energy consumption than the network density. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Value** \\ \hline Network size & 3000 m \(\times\) 1500 m \(\times\) 3000 m \\ Number of sinks & 16 \\ Number of nodes & 100–310 \\ Distribution & Random \\ Initial Energy & 70 \\ Transmission powers & (8.5, 35, 55) W \\ Maximum transmission range & (500, 1200, 2000) m \\ Data packet size & 150 bytes \\ Frequency & 37.400 kHz \\ Data rate & 18,700 bps \\ s (shipping) & 0.5 \\ w (wind) & 4 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Summary of Scenario Two Simulation Parameters. The 95% confidence interval error bars in Figure 10 show that our EEDOR-VA protocol has a smaller error range, mainly with a low transmission power level. Additionally, the EEDOR-VA error range decreases as the network density increases. The small error range indicates that the energy depletion is more stable between all the nodes in the topology. In DBR, the large variation in mean energy consumption per node occurs because of the flooding technique, where some of the nodes with lesser depth, especially those near the surface, retransmit more frequently since DBR does not incorporate any energy balancing strategies. EEDOR and EEDOR-VA waiting time techniques assist in the next-hop forwarders collaboration to transmit the data packet and balance the energy consumption by suppressing the retransmissions. Figure 10: _Cont._  
Figure 9: Total energy consumption comparison at different transmission powers. **Total Number of Transmissions:** To clarify the extensive variance between the total consumed energy of DBR and both of our protocols, EEDOR and EEDOR-VA, we calculate the total number of nodes participating in data packet transmissions starting from the source node until reaching the sink for all three protocols using the three power levels. Figure 10(c) shows that DBR has the largest total number of nodes that transmit the packet, and this number increases with increasing the network density. The increase in the total number of transmitting nodes in the DBR protocol as the network density increases happens due to the greedy flooding technique used by the protocol to forward the data packet. In contrast, both EEDOR and EEDOR-VA use the proposed waiting time to allow the lower priority forwarding nodes to hear the higher priority node transmissions. This yields a much smaller total number of transmitting nodes. Moreover, the subfigures show that the numbers of transmitting nodes for EEDOR and EEDOR-VA become closer to each other  
Figure 11: Number of transmissions comparison at different transmission powers. Figure 10: Comparison of mean total energy consumption per node at different transmission powers. with a higher transmission power level.