# Two-Level Sharing and Extraction of Sensing Information with Hybrid V2X Communications
## 5 Performance Evaluation
### Evaluation Results
After the second round exchange, the number of vehicles that needed to make a global report was reduced to 3.3. After the third round exchange, the number of vehicles that needed to make global report did not change. Figure 6: Network topology in Scenario 1 ( node ID 0: BS/AP). Figure 8: Collection of reports at the edge server in Scenario 1 regarding the proposed scheme. Figure 7: MinFactor at each vehicle in each exchange round in Scenario 1 regarding the proposed scheme. Figure 9: Average report number in Scenario 2. Figure 10 illustrates the result of the average amount of consumption of wireless resources in terms of accumulated interference area in the extraction of sensing information with local cooperation among vehicles in Scenario 1. The proposed scheme resulted in a more than 80 percent reduction of wireless resource consumption compared with the direct report scheme. This is because the short communication range is utilized in the local exchange between vehicles and the unnecessary global reports are restrained. Figure 11 shows the necessary number of vehicles that needed the global report of results to the edge server in Scenario 3 regarding the proposed scheme. The number of global reports before the local exchange of sensing information was 30. After the first round of local exchange, there were only 4 vehicles that needed to report its sensing results to the edge server. After the second round of local exchange, there was only 1 vehicle that needed to report its sensing results to the edge server. We think that the decrease in the global report number was caused by the local extraction of object sensing information and the prohibition of unnecessary reports at each vehicle. Figure 11: Number of necessary reports to the edge server in Scenario 3 regarding the proposed scheme (State 1 refers to the state in which the vehicle needs to report to the edge server). Figure 10: Average resource consumption in Scenario 2. To confirm the connectivity among vehicles, we examined the graph features of vehicles. Figure 12 shows the graph topology of the corresponding vehicles examined in Scenario 3. There is only one component in the graph of vehicles that utilized a local communication range between them. Figure 13 shows the result of MinFactor, which was extracted at each vehicle during the exchange of sensing results among vehicles in Scenario 3 regarding the proposed scheme. Although the MinFactor at the vehicles were initially diverse before the exchange of sensing results, there was a significant decrease in the diversity of MinFactor among vehicles after the first round of exchange, and the diversity of MinFactor information came to a consensus. Figure 12: Network topology in Scenario 3 ( node ID 0: BS/AP). Figure 13: MinFactor at each vehicle in each exchange round in Scenario 3. Figure 14 illustrates the collection of reports at the edge server in Scenario 3 regarding the proposed scheme. There was one report collected at the edge server after the local extraction of sensing information. The final result of MinFactor was \(-99\). Figure 15 shows the average number of global results corresponding to each round of local exchange among vehicles in Scenario 4. After the first round exchange, the proposed scheme resulted in 2.3 vehicles that needed to report their sensing results to the edge server. After the second round exchange, the number of vehicles that needed to make a global report was reduced to 1.2. After the third round exchange, the number of vehicles that needed to make global report did not change. Figure 16 illustrates the result of the average amount of consumption of wireless resources in terms of accumulated interference area in the extraction of sensing information with local cooperation among vehicles in Scenario 4. The proposed scheme results in a more than 70 percent reduction of wireless resource consumption compared with the direct report scheme.