# A Glider-Assisted Link Disruption Restoration Mechanism in Underwater Acoustic Sensor Networks
## 5 Performance Evaluation
### Evaluation with Different Parameters
\begin{table}
\begin{tabular}{c c} \hline \hline
**Name** & **Values** \\ \hline Monitoring volume & 6 km \(\times\) 4 km \(\times\) 4 km \\ Transmission speed & 1.5 km/s \\ Transmission range & 1.5 km \\ DATA packet size & 300 B \\ Maximum gliding depth & 4 km \\ steady-state gliding maximum pitch angle & 69.5\({}^{\circ}\) \\ steady-state gliding minimum pitch angle & 9.2\({}^{\circ}\) \\ Maximum gliding speed & 2 Kn (1.852 km/h) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Simulation parameters. a certain amount of time and energy on reconstructing back to the original optimal state. When a link in the network is disrupted for 1000 s, for the glider-assisted link disruption restoration mechanism, the previous process is continued for link restoration. For other algorithms, however, the link repair is not done within the simulation time. This may be due to the link between the key nodes being disrupted, for example, the link between the cluster head node and its upper-level node, so that the link cannot be repaired no matter how the path is detoured or the topology is reconstructed. Only when the link environment changes again these mechanisms may restore the disrupted link to the original state, thereby restoring link connectivity. At this time, the advantages of the glider-assisted link disruption restoration mechanism are obvious: the glider-assisted link disruption restoration mechanism has a strong general nature and it can adapt to a variety of different conditions. Figure 4: Relationship of the delivery ratio with different values of \(s/h\). Figure 5: The end-to-end delay of network. The scenario of Figure 6 is synchronized with Figure 5, which shows the connectivity of the link as time goes by. In this simulation, we use binary numbers to indicate the connectivity and disruption status of link. The state 1 indicates that the link is connected, and the opposite state 0 indicates the link is disrupted. As shown in Figure 6, when the link status changes from 1 to 0 at 200 s, the link is disrupted, and the OVAR, HHVBF and VBF resume the link connectivity within a relatively shorter period of time. The glider-assisted link disruption restoration mechanism takes a relatively longer time to complete the link restoration task, and the link status changes from 0 to 1, until 1000 s, the link state has changed from 1 to 0, that is, another link disrupted. However, the OVAR, HHVBF and VBF cannot complete the link repairing during the simulation time. However, the glider-assisted link disruption restoration mechanism still completes the link restoration without any difference and restores the initial connectivity of the network. This shows that the glider-assisted link disruption restoration mechanism is more generally applicable. Energy is also an important factor to consider since the common sensor nodes in UASNs are mostly battery-powered. The storage capacity of batteries is limited and underwater charging technology is more difficult to achieve. For common nodes, its energy consumption is mainly used to collect sensor data, send data packets, forward data packets and receive data packets, and we define these energy consumption as communication energy consumption. Therefore, communication energy consumption is an important measure of the life of a common sensor node. That is, the less energy consumption to deliver the same packet to the aggregation node can prolong the life of the node, thereby prolonging the life of the entire network. Therefore, in order to verify the performance of the glider-assisted link-disruption restoration mechanism, we compare its communication energy consumption with OVAR, HHVBF and VBF, as shown in Figure 7.  
It can be seen from Figure 7 that the increase rate of communication energy consumption of the glider-assisted link disruption restoration mechanism is almost unchanged as the rate of increase of OVAR, HHVBF and VBF increases.