Secure Ultra-Reliable and Low Latency Communication in UAV-Enabled NOMA Wireless Networks

Combing unmanned aerial vehicles (UAVs) with nonorthogonal multiple access (NOMA) in ultra-reliable and low latency communication (uRLLC) is deemed as a new service category of 5 G wireless networks. The openness nature of wireless environment makes security of information transmission unprecedentedly importance. Traditional cryptography methods cannot cater to uRLLC due to high complex design and processing delay. As a result, physical layer security (PLS) has been designed to secure information transmission by exploiting intrinsic property of wireless channel. However, many prior works ignored the role of UAV in study of PLS in uRLLC, and mobility of UAV deserves further investigation. This paper studies security and reliability performances of UAV-based uRLLC by using NOMA, where two kinds of users with different requirements are served, i.e., users with privacy and low latency requirement (PLR), and users with reliability and low latency requirement (RLR). With the tools of stochastic geometry, we formulate the secrecy rate, a popular metric in study of PLS, by establishing the closed-form expressions for static and dynamic UAV. Key system parameters (e.g., transmit power allocation) are optimized for secrecy rate maximization. Simulations evaluate theoretical analysis and give a significant insight into a positive secrecy rate for the network designer.