On the Effects of Mobility Uncertainties on Wireless Communications between Flying Drones in the mmWave/THz Bands

Millimeter wave and terahertz (mmWave/THz) band communications are a promising technology to alleviate the looming spectrum crunch crisis in traditional RF spectrum bands. This article investigates the challenges in enabling mmWave/THz-band communications for wireless drone networking. To reduce the negative effects of high atmospheric absorption and path loss in radio in-air communications in the mmWave/THz bands, directional transmissions have been widely adopted. However, the directional mmWave/THz links with narrow beamwidth can be easily degraded or disconnected because of the misalignment between the transmit and receive antennas of the communicating drones. To address this challenge, in this article we take an initial step towards understanding the effects of mobility uncertainties on mmWave/THz-band communications between flying drones. We first conduct a series of field experiments to measure the mobility uncertainties of flying drones in micro, small and large scales. Then, the capacity of the mmWave/THz links achievable in the presence of mobility uncertainties is analyzed. Results indicate that micro-scale mobility has only negligible effects on the link capacity (less than 1 %), while the wireless links may experience significant capacity degradation (over 50 %) in the presence of small- and large-scale mobility.