Mobility in the Sky: Performance and Mobility Analysis for Cellular-Connected UAVs

TL;DR

This paper analyzes the performance and mobility of cellular-connected UAVs using coordinated multi-point transmission, deriving bounds on coverage probability and studying the impact of system parameters for static and mobile UAV user equipments.

Contribution

It introduces a novel framework for analyzing UAV connectivity with coordinated multi-point transmission, providing bounds and insights into system parameter effects.

Findings

Coverage probability of high-altitude UAVs is limited by antenna tilt.

CoMP transmission significantly improves UAV coverage at low SIR thresholds.

Performance depends on collaboration distance, UAV altitude, and velocity.

Abstract

Providing connectivity to unmanned aerial vehicle-user equipments such as drones or flying taxis is a major challenge for tomorrow cellular systems. In this paper, the use of coordinated multi-point transmission for providing seamless connectivity to UAV user equipments is investigated. In particular, a network of clustered ground base stations that cooperatively serve a number of UAVUEs is considered. Two scenarios are studied: scenarios with static, hovering UAV user equipments and scenarios with mobile UAV-UEs. Under a maximum ratio transmission, a novel framework is developed and leveraged to derive upper and lower bounds on the UAV-UE coverage probability for both scenarios. Using the derived results, the effects of various system parameters such as collaboration distance, UAVUE altitude, and UAV-UE velocity on the achievable performance are studied. Results reveal that, for both static and mobile UAV user equipments, when the BS antennas are tilted downwards, the coverage probability of a high-altitude UAV-UE is upper bounded by that of ground users regardless of the transmission scheme. Moreover, for low signal-to-interference-ratio thresholds, it is shown that CoMP transmission can improve the coverage probability of UAV user equipments, e.g., from 28% under the nearest association scheme to 60% for a collaboration distance of 200m.