UAV-Based Relays Using Active Phased Arrays for Non-Line-of-Sight Millimeter-Wave Communications: Real-Time Field Testing

This paper presents an unmanned aerial vehicle (UAV)-based relay that leverages active phased arrays for non-line-of-sight millimeter-wave (mmWave) communications. First, the contribution of UAV-based relays to the link budget is analyzed as a function of transmitting and receiving active arrays. Furthermore, the details of the UAV-based relay, ground base station, and user equipment are described. The hardware development of the three aforementioned parts forms a unique testbed that enables the conduct of real-time and end-to-end experiments. The proposed testbed was initially validated in-lab conditions and used later to enable real-word in-field testing. Specifically, two 4×4 39 GHz active antenna arrays are used as part of the UAV payload, enabling the streaming of high-definition video content between widely spaced transmitting and receiving stations separated by an obstructing building.