Performance Analysis of NOMA‐Based Hybrid Cognitive Network With Rotating UAV for Enhanced Spectrum Efficiency

Abstract

This study investigates the performance of a cooperative non‐orthogonal multiple access (NOMA)‐based hybrid cognitive radio (CR) network aided by rotating unmanned aerial vehicle (UAV). RF energy harvesting, Nakagami‐m fading between terrestrial users, and line‐of‐sight (LOS) linkages between UAV and different users have been taken into account for this proposed CR network. UAV rotates periodically over a circular region of interest (CROI) to locate ideal primary user (PU) bands, which is used by UAV to establish links between secondary users (SU) that experience severe fading on direct connections. All sources and the UAV make sensing judgments and transmit them to the fusion center (FC) in order to collaboratively determine the condition of a PU band using AND rule. According to the fusion center result, SU and UAV make adaptive transition between overlay and underlay protocols in order to improve spectrum efficiency (SE) of the system. The secondary throughput for NOMA‐based rotating UAV‐equipped CR networks under conditions of imperfect successive interference cancellation (i‐SIC) has been evaluated through closed‐form mathematical expressions. The proposed system throughput is examined for different network factors, like the radius of the UAV trajectory, height of UAV, and harvesting angle. Lastly, every analytical closed form equation has been validated using the MATLAB simulation testbed.