# A Comprehensive Evaluation Algorithm of Multi-Point Relay Based on Link-State Awareness for UANETs
## 4 Route Control Overhead  
The control overhead ratios for each protocol are depicted in Figure 10. Overall, the average cost ratios of control messages for CEL-OLSR, PM-OLSR, ML-OLSR, LD-OLSR, and OLSR protocols are 40.02%, 41.51%, 42.90%, 44.61%, and 41.16%, respectively. The detailed results for each protocol at different speed stages can be found in Table 5. A lower proportion of control messages implies a higher volume of actual data packet transmissions, which aligns with our expectations. While the overhead for CEL-OLSR also gradually increases with rising node speed, the rate of increase in control overhead slows down.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Speed Stage** & **Speed** & **CEL-OLSR** & **PM-OLSR** & **ML-OLSR** & **LD-OLSR** & **OLSR** \\ \hline \multirow{3}{*}{Low speed stage: 10 m/s\(\sim\)20 m/s} & 10 m/s & 27.3271 Kbps & 26.2906 Kbps & 24.4521 Kbps & 22.3386 Kbps & 14.5856 Kbps \\  & 15 m/s & 26.9345 Kbps & 25.6102 Kbps & 22.8175 Kbps & 20.9329 Kbps & 13.4219 Kbps \\  & 20 m/s & 25.2784 Kbps & 24.0471 Kbps & 21.7056 Kbps & 18.0408 Kbps & 13.1396 Kbps \\ \hline \multirow{3}{*}{Mid low-speed stage: 25 m/s\(\sim\)35 m/s} & 25 m/s & 24.8241 Kbps & 23.5923 Kbps & 19.8765 Kbps & 16.2763 Kbps & 12.0620 Kbps \\  & 30 m/s & 23.7894 Kbps & 21.7894 Kbps & 18.1109 Kbps & 14.9236 Kbps & 11.8063 Kbps \\  & 35 m/s & 21.7406 Kbps & 19.7406 Kbps & 16.9021 Kbps & 13.8289 Kbps & 11.1214 Kbps \\ \hline \multirow{3}{*}{Mid high-speed stage: 40 m/s\(\sim\)50 m/s} & 40 m/s & 19.4539 Kbps & 17.4539 Kbps & 15.6454 Kbps & 12.2358 Kbps & 10.5553 Kbps \\  & 45 m/s & 18.7141 Kbps & 16.5141 Kbps & 14.2456 Kbps & 11.7693 Kbps & 10.5621 Kbps \\ \cline{1-1}  & 50 m/s & 17.5242 Kbps & 15.2542 Kbps & 13.7857 Kbps & 10.8997 Kbps & 9.0364 Kbps \\ \hline \hline \end{tabular}
\end{table}
Table 4: Results of throughput for comparison protocols at different speed stages.  
Figure 10: The comparison of control overhead rate among CEL-OLSR, PM-OLSR, ML-OLSR, LD-OLSR, and OLSR protocols.  
Figure 9: The comparison of network throughput among CEL-OLSR, PM-OLSR, ML-OLSR, LD-OLSR, and OLSR protocols.  
In high-speed mobile environments, frequent changes in network topology necessitate continuous updating and exchanging of routing information, resulting in a significant increase in control message overhead. In such environments, the intensification of link instability leads to more common occurrences of link breaks and reconstructions, compelling the system to transmit more link state control messages to maintain the accuracy of link information. Simultaneously, in the quest for optimal paths, the system must escalate the frequency of path detection and confirmation operations, further relying on the frequent exchange of control messages. The instability of links and path alterations also heighten the packet loss rate, prompting more retransmission requests, which often necessitate additional control messages for coordination. Additionally, the dynamically changing network environment demands more sophisticated congestion control and traffic management mechanisms to effectively administer network resources and circumvent congestion. Consequently, as node mobility increases, to uphold communication stability and efficiency, the system must augment the frequency of sending control messages, thereby significantly consuming network bandwidth and escalating node energy consumption. This surge in overhead is particularly pivotal in energy-constrained wireless network environments.