# A Multi-Technology Communication Platform for Urban Mobile Sensing
## 5 Results
### Network Analysis
#### 5.3.2 Mobile Opportunistic Vehicular Evaluation  
For the evaluation of the opportunistic delay-tolerant network (mOVE architecture), the obtained results for each evaluated strategy are presented. They show an analysis of the overall transmitted data packets to other mobile nodes; the delivery ratio; the cumulative end-to-end (E2E) delivery delay; and the total network overhead. The results for the overall transmitted data packets within the opportunistic network for each evaluated forwarding strategy are presented in Figure 17. They represent the percentage of data packets that each network node transmitted to others.  
Through the analysis of the results, we can conclude that mobile nodes with fewer transmitted packets to other mobile nodes are the ones that presented a poorer mobility pattern, i.e., the ones that performed no or fewer trips. A smaller number of trips implies less frequent contacts with the other network nodes, leading to smaller numbers of transmitted packets. This fact was observed in node-102, for the Epidemic strategy (day 1), in node-103 for the Contacts-Based Controlled Replication with Neighborhood Classification (day 2), and finally in node-101 for the Mobility-Based Controlled Replication with Neighborhood Classification strategy (day 3). Such premises can be confirmed by observing the flow of each network node in Figures 10, 11, and 12.  
Figure 16: Overall backoff usage (**a**) Day 1; (**b**) Day 2; (**c**) Day 3.  
Figure 17: Results of overall transmitted data packets to other mobile nodes.  
The results with respect to the delivery ratio for each evaluated strategy are shown in Figure 18. They represent the ratio between the delivered data packets to a gateway and the overall data packets within the network.  
As expected, the Epidemic has the highest delivery ratio. Since the Controlled Replication with Neighborhood Classification strategies carry out a trade-off between the amount of network replication and network congestion, a lower delivery ratio allied with a lower network overhead was expected as compared to the Epidemic method. Both strategies (contacts-based and mobility-based) presented similar behaviors (with a final delivery ratio difference of approximately 15%). Part of that difference is due to the distinct mobility patterns that each node presented between the two evaluation days.  
The results with respect to the cumulative end-to-end delivery delay for each evaluated strategy are shown in Figure 19. They represent the amount of time that a data packet takes from its generation until it has reached a gateway.  
As expected, the strategies with lower delivery ratios are the ones with higher delivery delay. The overall high delivery delay presented by the network is due to the fact that the presented results consider seven hours of evaluation, and there is a short period of data acquisition, specifically one packet every six seconds. The short sensing period was selected to allow us to analyze the behavior and performance of the network with considerable amounts of information flowing.  
The results with respect to the network overhead for each evaluated strategy are presented in Figure 20. They show the number of redundant data packets that each strategy introduces in the  
Figure 19: Cumulative network E2E delay results.  
Figure 18: Delivery ratio results.  
network. As expected, the Epidemic strategy introduces the highest network overhead due to its blind replication process without any limitations. Regarding both Controlled Replication with Neighborhood Classification strategies, it is observed that the contacts-based method has a lower network overhead. This was expected since this strategy presented a poorer network node mobility pattern, leading to a less data packet replication and consequently, a lower network overhead.