## 6 Results and Discussion
### Comparison with the Application's QoS Requirements
#### 6.2.2 Data Traffic Rate (DTR)  
In this section, we evaluate the impact of the DTR on the network performance. We consider three different scenarios (Seen 1, Seen 5, and Seen 6) with different DTR values, as Table 4 shows. Figure 15 depicts the data delivery rate for up to four applications running simultaneously. For a single application (Figure 14(a)), it is clear that the high DTR values significantly reduced the data delivery rate. Thus, Seen 6, which has the highest DTR value, presented the worst values. This occurs since the higher data traffic rate leads to more congestion and increases the probability of packet drop due to the buffer fullness. For Seen 1 and Seen 5, the AA approach ensured the data-delivery rate requirement for network sizes up to 225 nodes, compared with network sizes up to only 36 nodes in the case of Seen 6. To justify these findings, it should be noted that for a network size of 100 nodes, for instance, 98 data messages are sent per minute in the case of Seen 1 and Seen 5, compared with 5880 data messages per minute for Seen 6. For two applications, Figure 14(b) shows that Seen 1, with the lowest DTR value, continues to present better values than Seen 5 and Seen 6 for all cases. For the first and second applications, the satisfied network sizes are reduced from 196 nodes for Seen 1 to 100 nodes and 36 nodes for Seen 5 and Seen 6, respectively. Concerning the three applications, Figure 14(c) depicts that for the third application, which has a delivery rate requirement of 90%, the sizes of the satisfied networks increased from 36 nodes in the case of Seen 6 to 64 nodes and 225 nodes for Seen 5 and Seen 1, respectively. For four running applications, as Figure 14(d) shows, Seen 6, the scenario with the highest DTR value, continues to present the worst data-delivery rate values compared with Seen 1 and Seen 5. This is also applied to the fourth application, which has no priority. For a network size of 225 nodes and the fourth application, the data-delivery rate was 51.72% for Seen 1, compared with 44.53% and 26.81% for Seen 5 and Seen 6, respectively. Concerning data delay, Figure 16 depicts that for a single application (Figure 15(a)), Seen 6 presents the highest delay values since it has the highest DTR value. Seen 1 and Seen 5 present similar values for the different network sizes. This occurs because there is  
Figure 14: Control delay, changing the MCR value. just one application, and the DTR values for both Scen 1 and Scen 5 are hence equal. The delay requirement keeps ensuring network sizes up to 144 nodes for Scen 1 and Scen 5, compared with 64 nodes for Scen 6. For the case of two applications and the first application, as Figure 15(b) shows, the AA approach ensures the delay requirement for network sizes up to 100 nodes for Scen 1, compared with 144 nodes for the single application case. This could be justified using the second application, which raised the network traffic and prevented ensuring the delay requirement for network sizes larger than 100 nodes. The second application has a delay requirement of 950 ms, and the AA approach ensured the requirement for up to 100 nodes, 64 nodes, and 36 nodes for Scen 1, Scen 5, and Scen 6, respectively. For three and four running applications (Figure 15(c),d), the DTR value is directly proportional to the obtained delay values for all cases. This means that the scenarios with higher DTR values presented higher delay values. Concerning the fourth application, it presents the worst delay values since it is accommodated using a single timeslot and has no priority. For a network size of 196 nodes, the obtained delay values were 10.37 s, 16.37 s, and 24.37 s for Scen 1, Scen 5, and Scen 6, respectively. These values confirm, again, the high effect of the selected DTR value on the delay requirement. Figure 16(b) shows that the control overhead increases with the number of nodes, regardless of the DTR value and the number of applications.