# A Preemptive-Resume Priority MAC Protocol for Efficient BSM Transmission in UAV-Assisted VANETs
## 5 Numerical Results
#### Analysis of Delay and Processed Packet Volume under Different Arrival Rates  
For scenario 1, we selected \([\lambda_{\text{v1}};\lambda_{\text{v2}};\lambda_{\text{v3}}]=[0.05;0.1;0.15]\) and defined the collision probability \(\mathrm{P}\) based on the number of vehicles or messages, where a higher number of messages corresponds to a higher probability of packet collisions, \([\mathrm{P}_{1};\mathrm{P}_{2};\mathrm{P}_{3}]=[0.0037778;0.045102;0.1299]\). For scenario 2, we selected \([0.1;0.1;0.05]\) and defined the collision probability \(\mathrm{P}\) based on the number of vehicles or messages, considering the case where higher priority packets need to take into account the presence of low priority packets in effective collisions, \([\mathrm{P}_{1};\mathrm{P}_{2};\mathrm{P}_{3}]=[0.01185;0.0638;0.1508]\). According to Figure 8a, the model follows a Poisson distribution, and it shows the number of vehicles in different speed ranges under the condition of \([\mathrm{K}_{1};\mathrm{K}_{2};\mathrm{K}_{3}]=[45;100;128]\). According to Figure 8b, the model follows a Poisson distribution, and it shows the number of vehicles in different speed ranges under the condition of \([\mathrm{K}_{1};\mathrm{K}_{2};\mathrm{K}_{3}]=[127;105;59]\). According to the simulation and Figure 9a, the average speed in different speed ranges is \([\overline{v_{\text{H}}};\overline{v_{\text{E}}};\overline{v_{\text{S}}}]=[ 37.37;29.19;20.89](\text{m}/\text{s})\). The average passage time in different speed ranges is \([\overline{v_{\text{U}}};\overline{v_{\text{U}}};\overline{v_{\text{E}}}; \overline{v_{\text{S}}}]=[26.77;34.26;47.86](\text{s})\). According to Figure 9b, it can be observed that the difference between scenarios 1 and 2 lies in the varying arrival rates, which in turn lead to different numbers of vehicles. However, there is not much impact on the average values of different vehicle speeds or the average passage times. the average speed in different speed ranges is \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Parameter Name** & **Data** & **Parameter Name** & **Data** \\ \hline W & 32 & PHY header \((\text{HPIFY})\) & 192 bits \\ m & 5 & Prop delay \((\delta)\) & 2 μs \\ Slot time \((\sigma)\) & 20 μs & SIFS & 10 μs \\ MAC header \((\text{H}_{\text{MAC}})\) & 224 bits & ACK & 112 bits + \(\text{H}_{\text{PHY}}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: MAC Layer and Queuing Delay Parameter Table. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Parameter Name** & **Data** & **Parameter Name** & **Data** \\ \hline UAV altitude \((\text{h}_{\text{u}})\) & 50 m & Path loss exponent & 2 \\ Road length \((\text{D})\) & 1000 m & \(\text{t}_{\text{LoG}}\) & 1 DB \\ a & 9.6 & \(\text{t}_{\text{NLLoG}}\) & 20 DB \\ b & 0.28 & Vehicle transmission & 10 W \\   Speed of light \((\text{c})\) & \(3\times 10^{8}\) m/s & Noise \((\text{I}_{\text{C}}+\text{N}_{0})\) & \(-120\) DB \\ Carrier frequency \((\text{f}_{\text{c}})\) & 2.4 GHz & Bandwidth \((\text{W}_{\text{up}})\) & \(1\times 10^{7}\) bit/s \\ \hline \hline \end{tabular}
\end{table} 
Table 3: G2A Link Delay Parameter Table. \([\overline{V_{\overline{1}}};\overline{V_{\overline{2}}};\overline{V_{\overline{3}}} ]=[37.57;28.69;21.24](\text{m/s})\). The average passage time in different speed ranges is \([\overline{t_{\overline{v}1}};\overline{t_{\overline{v}2}};\overline{t_{ \overline{v}3}}]=[26.62;34.85;47.07](\text{s})\). The specific data in Figure 10a are as follows: \([\overline{S_{1}};\overline{S_{2}};\overline{S_{3}}]=[4.616;7.106;16.54](*10^ {-4}\text{s});\)\([\overline{W_{1}};\overline{W_{2}};\overline{W_{3}}]=[5.372;30.59;236.3](*10^{-8} \text{s})\), \([\overline{T_{1}};\overline{T_{2}};\overline{T_{3}}]=[4.616;7.111;16.58](*10^ {-4}\text{s})\). Figure 10a shows that due to the low number of vehicles in the higher priority segment (Priority 1) and the smaller collision probability P at the stations, the vehicles in the higher speed range can send data packets with little waiting time and have shorter processing times compared to other speed ranges.