# A Preemptive-Resume Priority MAC Protocol for Efficient BSM Transmission in UAV-Assisted VANETs
## 6 Conclusions  
In this paper, we proposed an algorithm based on UAV-assisted VANETs for prioritizing data transmission and interaction between vehicles and UAVs, considering the speed of the moving vehicles. This algorithm was used to allocate limited wireless communication  
Figure 13: Comparison of Other Models and Preemptive Models. (**a**) With FPMDC-MAC and (**b**) with Wang’s Model.  
resources and ensure priority for the transmission of safety-critical information, such as traffic information. To achieve this, we designed an improved 802.11 CSMA/CA MAC layer access protocol equipped with an arbitrator. Additionally, we established a preemptive M/G/1 queuing theory model based on this network and calculated the data delay. By prioritizing the transmission requirements of the highest-priority moving vehicles in safety-related information transmission, we addressed the problem of minimizing total delay. We further transformed the problem of minimizing total delay within the same UAV coverage area into a problem of minimizing BSM transmission intervals. Finally, through simulation experiments, we validated the effectiveness of the proposed method in this paper. The simulation results demonstrated that under different arrival rates, this mechanism could reduce the transmission intervals for high-speed vehicles, thereby improving the efficiency of information transmission for high-speed driving vehicles and meeting the network performance requirements of safety driving applications in intelligent transportation systems.  
At the time of this research, certain limitations existed in our work. First, this paper only considered the uplink transmission from vehicles to the relay portion; the downlink transmission from the relay back to the user vehicles will be investigated in future studies. Second, our research focused primarily on the V2I communication mode, but future work is needed to incorporate V2V communication for further expansion. Additionally, it is important to note that our simulation results are numerical solutions, and therefore, future studies will involve utilizing other simulation software to conduct further research and validate the practical implications of our findings. In order to further enhance our research, we plan to address these limitations and conduct a more comprehensive exploration in future studies.  
Conceptualization, J.L., T.H. and W.G.; Methodology, T.H.; Validation, J.L., T.H., W.G. and X.L.; Formal analysis, J.L. and T.H.; Investigation, T.H.; Writing--review and editing, J.L. and T.H.; Supervision, J.L., W.G. and X.L.; Project administration, J.L. and X.L. All authors have read and agreed to the published version of the manuscript.  
This work was funded by the Beijing Municipal Education Commission (KM202310011002) and the General Program of Educational Teaching Reform Research Project at the Beijing Technology and Business University (jg225210).  
Not applicable.  
Data Availability Statement: Data are contained within the article.  
We would like to thank the anonymous reviewers for their valuable and insightful comments.  
The authors declare no conflicts of interest.