# Comprehensive Review of UAV Detection, Security, and Communication Advancements to Prevent Threats
## 9 Open Research Areas and Recommendations  
After studying the previous sections, it is noted that there is still a need to improve some of the areas associated with unmanned aerial vehicles (UAVs). These areas are very significant and one may address these concerns to enhance the utilization of drones [73; 74]. One of the important areas is path loss, where one needs to propose the channel model to hold on to the communication at higher carrier frequencies, and even in the presence of tall concrete buildings. This area is in regard to the latency in the communication, which should be less than 1 millisecond and remains as an area of concern [75; 76]. In addition to these areas, one may work over the reliability aspect, where one may improve the drones with ultra-reliable communication so that even with the increase in UAVs in the sky, the communication can be performed easily. It is noted that these drones have not been operated in the sky for a long time, which is because of the battery life. Hence, battery optimization for drones is also one of the areas where researchers may engage themselves to increase the flight time. Last, but certainly not least, is the amalgamation of artificial intelligence and computer vision algorithms in a drone to improve the mobility of the drone without any collision. This will protect the drone in terms of data logging and security [77; 78; 79; 80; 81; 82; 83; 84]. This manuscript also suggests some of the recommendations that may improve the privacy and security aspects, such as the registration of drone licenses. This will ensure the authorities identify the specific drone that has created an inconvenience in the jurisdiction [85; 86; 87; 88; 89; 90; 91]. Moreover, there must be flying permits allotted after necessary training to limit the illegal utilization of drones in any activity. Another recommendation is to educate the public about the legal and illegal usage of such autonomous unmanned aerial vehicles and the laws related to it so that if they witness anything around, they may easily report it. In any vicinity, there are some restricted zones; thus, the market drones must be operated based on a built-in map [92; 93; 94; 95] as per the local regions. In this way, when any drone is forced to enter into any barred jurisdiction, it will automatically revert to the ground using the vertical take-off and landing (VTOL) mode. In terms of security tools, this paper proposes the machine learning-based IDS system [96; 97; 98] to improve the security infrastructure of UAVs, and lastly, there should be rigid multi-factor authentication methods that tackle the security threats easily. There are several future recommendations to increase the standards for the security and privacy aspects of UAVs. These aspects are improved by proposing an approach which is based on a pairing certificate so that other strange entities may not easily connect or communicate with our UAV. Some of them are based on identification/authentication protocols [99; 100; 101; 102; 103]. To secure the drone more and make it less vulnerable, researchers have also used a symmetric searchable encryption method (SSE) [104] as well. Some researchers have proposed an internet of things (IoT) feature also for the same purpose [105; 106; 107; 108]. In terms of identifying an unknown input observance, one may see an intelligent control algorithm that stabilizes the UAV in the presence of an unknown input [108; 109; 110] and devise it in trajectory and altitude levels to identify unknown system dynamics online by utilizing filtering manipulations that possess a concise structure, low calculation consumption, and asymptotic error convergence. In addition to this, the manuscript highlights the major domains and compares them with some of the latest review papers on UAVs for contrast.