1,266 research outputs found
An Empirical Air-to-Ground Channel Model Based on Passive Measurements in LTE
In this paper, a recently conducted measurement campaign for
unmanned-aerial-vehicle (UAV) channels is introduced. The downlink signals of
an in-service long-time-evolution (LTE) network which is deployed in a suburban
scenario were acquired. Five horizontal and five vertical flight routes were
considered. The channel impulse responses (CIRs) are extracted from the
received data by exploiting the cell specific signals (CRSs). Based on the
CIRs, the parameters of multipath components (MPCs) are estimated by using a
high-resolution algorithm derived according to the space-alternating
generalized expectation-maximization (SAGE) principle. Based on the SAGE
results, channel characteristics including the path loss, shadow fading, fast
fading, delay spread and Doppler frequency spread are thoroughly investigated
for different heights and horizontal distances, which constitute a stochastic
model.Comment: 15 pages, submitted version to IEEE Transactions on Vehicular
Technology. Current status: Early acces
Flying Drones Beyond Visual Line of Sight Using 4G LTE: Issues and Concerns
The purpose of this paper is to address the extent in which 4G LTE can be used for air traffic management of small Unmanned Air Vehicles (sUAVs) and the limitations and enhancements that may be necessary. We provide a brief overview of the communications aspects of the Unmanned Aerial System (UAS) Traffic Management Project followed by the evolving trends in air traffic management including beyond visual line of sight (BVLOS) operations concepts and current BVLOS operational systems. Issues and Concerns are addressed including the rapidly evolving global regulations and the resulting communications requirements as well LTE downlink and uplink interference at altitude and how that interference affects command and control reliability as well as application data capabilities and mobility performance
A Survey on Cellular-connected UAVs: Design Challenges, Enabling 5G/B5G Innovations, and Experimental Advancements
As an emerging field of aerial robotics, Unmanned Aerial Vehicles (UAVs) have
gained significant research interest within the wireless networking research
community. As soon as national legislations allow UAVs to fly autonomously, we
will see swarms of UAV populating the sky of our smart cities to accomplish
different missions: parcel delivery, infrastructure monitoring, event filming,
surveillance, tracking, etc. The UAV ecosystem can benefit from existing 5G/B5G
cellular networks, which can be exploited in different ways to enhance UAV
communications. Because of the inherent characteristics of UAV pertaining to
flexible mobility in 3D space, autonomous operation and intelligent placement,
these smart devices cater to wide range of wireless applications and use cases.
This work aims at presenting an in-depth exploration of integration synergies
between 5G/B5G cellular systems and UAV technology, where the UAV is integrated
as a new aerial User Equipment (UE) to existing cellular networks. In this
integration, the UAVs perform the role of flying users within cellular
coverage, thus they are termed as cellular-connected UAVs (a.k.a. UAV-UE,
drone-UE, 5G-connected drone, or aerial user). The main focus of this work is
to present an extensive study of integration challenges along with key 5G/B5G
technological innovations and ongoing efforts in design prototyping and field
trials corroborating cellular-connected UAVs. This study highlights recent
progress updates with respect to 3GPP standardization and emphasizes
socio-economic concerns that must be accounted before successful adoption of
this promising technology. Various open problems paving the path to future
research opportunities are also discussed.Comment: 30 pages, 18 figures, 9 tables, 102 references, journal submissio
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