Doppler Shift Effect on Bandwidth Availability for UAV Communications

Unmanned Aerial Vehicle (UAV) use has experienced a remarkable surge across different applications in the past decade. Ensuring uninterrupted data connectivity to the Command and Control (C2) system becomes paramount for ensuring UAV safety and efficiency as deployment continues to grow; however, communication signals are susceptible to various factors that can disrupt bandwidth availability for C2 systems. Among these phenomena, Doppler shift significantly affects transmitted signals due to the UAV’s high speeds. This paper provides the results of a comprehensive investigation to quantify and evaluate the effect of Doppler shift on the available bandwidth for C2 systems. This study uses extensive simulations to analyze bit error rates (BERs) and IQ constellation diagrams of the received signals. The research methodology encompasses a range of parameters, including modulation scheme, code rate, Signal-to-Noise Ratio (SNR), and UAV velocity, enabling a comprehensive understanding of Doppler shift influence on available bandwidth. The results show a correlation between the UAV speed and the IQ constellation as well as the BER wherein BER increases with higher velocities, the utilization of more complex modulation schemes, or a decrease in SNR.