Validation of Large-Scale Propagation Characteristics for UAVs within Urban Environment

Abstract

Cellular networks based on current LTE Advanced or coming 5G technology, constitute an attractive candidate to provide communication links for drones in low level airspace. This paper extends previous findings on path loss exponent and shadow fading variation for an urban environment, by adding new and more extensive empirical evidence. Specifically, by way of the measurement methodology we study also the spatial correlation of the shadow fading, including the lateral spatial autocorrelation (decorrelation distance) and the crosscorrelation in shadowing variability between different heights. Data was obtained with the use of a drone flying at heights up to and above rooftop, using a radio network scanner for measuring live LTE signals at 1800 MHz. The path loss analysis confirmed the validity of previously presented modelling frameworks for the behaviour versus height, as well as the characteristics of the increased interference observed when the drone is above rooftop level. As for the spatial correlation of the shadow fading, the results indicate that decorrelation distance does not change appreciably from ground level up to and above rooftop level, and remains in the order of 10m. The shadow fading variability is generally uncorrelated versus height, although with a trend to be correlated below rooftop level, but not above.

A Survey of Wireless Networks for Future Aerial COMmunications (FACOM)

“…Regarding A2G channel measurements, the authors of [179], [181] derive a model with pathloss exponent and shadow fading in urban scenarios for the altitudes up to 40 m. The results show that the paths between the UAV and the BSs become more clear as the altitude of the UAV increases and the shadow fading is uncorrelated to the altitude. They further extend these studies by evaluating the feasibility of ray tracing models to predict the variations in the shadow fading [180].…”

“…Network Services eMBB-baased A2G network design and performance evaluation [170]- [173] Feasibility of MBB for A2G connectivity of helicopters/eVTOLs [174] Evaluation of (e)MBB for CNPC via UAV field measurements [5], [171], [175]- [178] A2G channel measurements and modeling for UAV CNPC [179]- [181] Evaluation of MBB for UAV-based video streaming [182], [183] Suitability of MBB for UTM-UAV connectivity [184], [185] uRLLC Multi-operator connectivity to improve communication reliability [186], [187] Coordinated Multipoint (CoMP) to improve aerial coverage [188], [189] Technology Network Softwarization SDN-based networking framework to support UAVs [190], [191] Performance evaluation of network slicing for UAVs [185] mmWave Beamforming and beamtracking to improve UAV A2G channel quality [192], [193] MEC MEC for end-to-end latency optimization [194], [195] MEC for the optimization of energy consumption of UAVs [195], [196] Issues and Challenges…”

Novel Unmanned Aerial Vehicle-Based Line-of-Sight MIMO Configuration Independent of Transmitted Distance Using Millimeter Wave

“…As communication traffic increases, the use of small autonomous unmanned aerial vehicles (UAVs) is attracting attention [12]. Experimental evaluation reports that when a UAV flying over buildings communicates with base stations using microwaves, the propagation loss approaches the square of the transmitted distance in proportion to the flight altitude [13]. According to the conventional propagation model, the propagation loss increases in proportion to the 3rd-4th power of the transmitted distance in an outdoor environment, assuming it is an urban area [14].…”

An UAV-Based Experimental Setup for Propagation Characterization in Urban Environment

“…Only a few studies have targeted A2G propagation in actual urban areas, probably due to the inherent difficulties in getting authorizations to fly on densely populated zones and/or close them to the public during measurements [13]- [17]. In some cases, the investigation has been limited to air-to-base-station propagation [9], [16], [17], which is an interesting but less challenging scenario, compared to communications from the UAV to users at street level. Moreover, in such studies, the analysis is mainly focused on large-scale parameters, such as path-loss, fading statistics, and spatial correlations, and is often limited to UHF or submillimeter-wave frequencies.…”