Research Challenges and Opportunities of UAV Millimeter-Wave Communications

Millimeter-wave (mmWave) communication with multi-gigahertz bandwidth availability enables much higher capacity and transmission rate than conventional microwave communications. However, mmWave signals suffer from propagation-related shortcomings. The flexibility of UAV communication can compensate most of the deficiencies of mmWave signals, preserve its advantages, and provide more opportunities. In this article, we present the current state of the art, research opportunities, and challenges for UAV mmWave communication. We present channel characteristics and show its modeling issues. We further analyze how to achieve UAV mmWave channel acquisition and precoder design. Moreover, we discuss the challenges and possible solutions for UAV mmWave cellular networks, including UAV-to-base-station and UAV-to-user communications and spectrum sharing.