## 5 Numerical Results
### Performance Analysis
#### 5.1.1 Performance Analysis for Emergency Packets  
Figures 5 and 6 show the changing trends in emergency packets' blocking rate \(\beta_{1}\) and throughput \(\theta_{1}\) under the proposed mixed mechanism.  
As shown in Figures 5 and 6, when the wakeup threshold \(H\) and adjustment factor \(\alpha\) change, emergency packets' blocking rate and throughput remain unchanged. This is because the wakeup threshold and dynamic access probability control the access and forwarding process for only non\(-\)emergency packets, and the system behaviour of non\(-\)emergency packets cannot affect emergency packets, which have preemptive priority. It also indicates that the proposed mixed mechanism can ensure the comprehensive forwarding performance of emergency packets.  
In Figures 5 and 6, we can find that as emergency packets' arrival rate \(p_{1}\) increases, emergency packets' blocking rate and throughput also increase under the parameter settings of this experiment. This is because the CH can forward a greater number of emergency packets if the arrival rate of emergency packets is higher, and emergency packets' through  
Figure 5: The changing trends in emergency packets’ blocking rate.  
Figure 6: The changing trends in emergency packets’ throughput.  
In Figures 7-9, as the wakeup threshold \(H\) increases, non\(-\)emergency packets' blocking rate and average latency show an upward trend. In contrast, the throughput shows a downward trend under the parameter settings of this experiment. This is because as the wakeup threshold increases, the CH will start forwarding non\(-\)emergency packets only when the amount of non\(-\)emergency packets stuck in the system increases. The number of successfully forwarded non\(-\)emergency packets per unit time decreases, resulting in a decrease in throughput. At the same time, more non\(-\)emergency packets are stuck in the cache, and the possibility of the cache being full is also higher, so the blocking rate and average latency both increase.  
Moreover, in Figures 7-9, when the adjustment factor \(\alpha\) increases, non\(-\)emergency packets' blocking rate decreases, while throughput and average latency increase under the parameter settings of this experiment. This has to do with the fact that dynamic access probability \(f\) is the probability of allowing non\(-\)emergency packets to access the system dynamically based on the load, and the larger the adjustment factor \(\alpha\), the higher the dynamic access probability. Therefore, the amount of non\(-\)emergency packets that voluntarily abandon access to the system for forwarding decreases, resulting in a corresponding decrease in blocking rate and an increase in throughput. At the same time, a large number of non\(-\)emergency packets are stuck in the cache after accessing the system, increasing average latency.  
In addition, from Figures 7-9, when emergency packets' arrival rate \(p_{1}\) increases, non\(-\)emergency packets' blocking rate and average latency also increase under the parameter settings of this experiment and throughput decreases. This is because, in this situation, the CH is more likely to be occupied by emergency packets, while a large number of non\(-\)emergency packets are stuck in the cache waiting to be forwarded, resulting in an increase in blocking rate and average latency and a decrease in throughput. Similarly, emergency packets' service rate has an opposite impact on the forwarding performance of non\(-\)emergency packets compared with the arrival rate.