# Cooperative Friendly Jamming Techniques for Drone-Based Mobile Secure Zone
## 6 Conclusions  
In this paper, we proposed the CFJ-DMZ method, which improves the security of wireless communication by using the mobility of mobile IoT devices and jamming signals, and we verified its effectiveness in drone communication environments. The drones conducting the cooperative friendly jamming move to locations where a secure D2D communication will be performed and transmit jamming signals to form a secure zone. The formed secure zone can effectively prevent eavesdropping and is flexible because the location and size can be easily changed. Furthermore, because jamming signals are transmitted only when the data transmitter and receiver communicate, the effect of the jamming signals on other source and destination nodes is minimized, and the batteries are efficiently used. Through the CFJ-DMZ model-applied simulations and fields tests, the BER of the eavesdropping devices was measured, which confirmed that the receiving performance of the eavesdroppers deteriorated, reducing the normal packet reception rate. Furthermore, we defined the ILR as a metric for a security performance evaluation and confirmed experimentally that the information leakage decreased with the proposed scheme.  
By integrating it with IoT networking environments across future social systems, including logistics, delivery, and unmanned moving objects, the proposed CFJ-DMZ method can be used not only for military drone communications but also as a model that can actually be commercialized. As a limitation of this study, the effects of jamming were examined in two-dimensional planes. To consider the intrinsic emission characteristics of RF, the effectiveness of the CFJ-DMZ method should also be verified in three dimensions. Furthermore, low latency is important for the proposed method to be applied to real-time systems, not only for delay-tolerant applications. However, in this study, time complexity could not be analyzed, and the study was conducted from the perspective of an information leakage ratio to verify whether confidential communication is possible using the proposed method. Therefore, experiments and verifications are required for various environments, including a case in which an eavesdropper enters the secure zone formed by the drones. In follow-up studies, we will make improvements on this limitation by applying actual environmental parameters to mathematical models and simulation models for assessment of time and resource complexity. Based on these studies, we expect to design a more advanced security architecture and increase the level of security in confidential and complex zones.  
Conceptualization, Y.-J.L., J.-H.L. and I.-G.L.; methodology, H.-J.P., [PERSON]-J.L. and J.-H.L.; software, Y.-S.S. and G.-H.J.; validation, Y.-S.S., H.-J.P. and Y.-J.L.; formal analysis, [PERSON]-H.J., Y.-S.S. and H.-[PERSON]; investigation, [PERSON]-[PERSON], [PERSON] and [PERSON]-[PERSON]; resources, [PERSON]-[PERSON] and [PERSON]-[PERSON]; data curation, [PERSON]-[PERSON] and [PERSON]-[PERSON]; writing--original draft preparation, [PERSON]-[PERSON], [PERSON]-[PERSON] and [PERSON]-[PERSON]; writing--review and editing, [PERSON]-[PERSON], [PERSON]-[PERSON], [PERSON] and [PERSON]-[PERSON]; visualization, [PERSON]-[PERSON] and [PERSON]-[PERSON]; supervision, I.-G.L.; project administration, I.-G.L.; funding acquisition, I.-G.L. All authors have read and agreed to the published version of the manuscript.  
Not applicable.  
The authors declare no conflict of interest.