# MCST Scheme for UAV Systems over LoRa Networks
## 7 Conclusions  
In this paper, we performed the network capacity improvement study of the MCST scheme over the LoRa networks. Besides, we proposed the mMCST/LoRa protocol by suppressing the control frames transmission to operate the MCST scheme. For performance evaluation, we performed two simulation scenarios of variance of frame payload size and the number of nodes in the network. Our simulation studies reveal that applying the MCST scheme in the LoRa network is possible. Furthermore, MCST/LoRa can give superiority up to 52% BRF throughput, 38% of latency, and 37% of energy consumption compared to existing LoRaWAN MAC, i.e., CSMA/LoRa. In addition, the proposed mMCST/LoRa protocol can achieve its superiority over the MCST/LoRa scheme and CSMA/LoRa, regardless of the frame size and the number of nodes in the network. The research works have contributed to the advantages of the transmission scheme, i.e., MCST and mMCST, in the LoRa network. Both schemes are designed to optimize the network capacity through the mixture of concurrent and sequential transmission in the network. If the implementation in the real network scenario is considered, the complexity of designing the mMCST scheme could be higher than the MCST scheme. As a preliminary network capacity study of the MCST scheme over the LoRa network, we simply consider the UAV systems as the application case study and concurrent transmission can be performed on the drone-to-drone communication. In this paper, the proposed MCST scheme contributes to reducing transmission latency that benefits the round trip time, which influences the TCP transmission throughput performance and quality of service of applications. However, this paper remains to consider the other parameters, i.e., the maximum size of an IP packet and packet loss rate, for fully considering the throughput performance of TCP connections, which can be considered as further future research works. Then, the consideration of hardware specification, medium access time, and collision management regarding the implementation in the real network scenario should be considered for a complete capacity improvement study. Besides that, future research should be extended with the performance investigation of the proposed protocol by considering the packet collision using the Markov Chain model and the network node mobility model.  
Conceptualization, A.T.P.K., L.S. and Y.L.; methodology, A.T.P.K., L.S. and Y.L.; validation, A.T.P.K., Y.L. and Y.T.; formal analysis, A.T.P.K. and Y.L.; investigation, A.T.P.K.; resources, A.T.P.K.; writing--original draft preparation, A.T.P.K.; writing--review and editing, A.T.P.K., L.S., Y.L. and Y.T.; visualization, A.T.P.K.; supervision, L.S., Y.L. and Y.T.; project administration, A.T.P.K. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
This work was supported in part by a Grant-in-Aid for Scientific Research (B) from the Japan Society for the Promotion of Science (JSPS), Japan. Grant number is 23H03381.  
The authors declare no conflict of interest.  
The following abbreviations are used in this manuscript:  
\begin{tabular}{l l} ACK & Acknowledgement \\ AI & Artificial Intelligence \\ ANS & Answer frame transmission \\ BRF & Basic relaying flow transmission \\ CSMA & Carrier sense multiple access \\ CSMA/LoRa & Carrier sense multiple access over LoRa network \\ CT & Concurrent transmission scheme \\ CTS & Clear-to-send \\ DCF & Distributed coordination function \\ \end{tabular}