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Design of “Drone Ready” Radio Access Network

Design of “Drone Ready” Radio Access Network
 

Nowadays, UAVs (Unmanned Aerial Vehicles), commonly known as drones, are being proposed for main  IoT (Internet-of-Things) scenarios: they are being used for several applications in real time video surveillance or environment monitoring, envisaged in the context of 5G ecosystems (verticals applications). These applications are typically limited when considering traditional dedicated point-to-point radio control, not suitable for a massive-UAV scenario: a cloud architecture based on 4G/5G mobile network can be the best solution to enable and optimize vertical services.
More specifically, UAV can play the role of a mobile sensor node that collects data from target sites and transfer it to the cloud, exploiting all cloud computing capabilities. On the other hand, a cloud based architecture allows remotely to set and coordinate critical missions for connected UAV’s. For this purpose, the UAV should relay both on good aerial wireless coverage and radio resources management able to control interference and optimally allocate resources.
In 2018 TIM launched Drones Ready Network project, an activity aimed to characterize and optimize radio coverage also at drone altitudes, in order to guarantee high quality services, manly in terms of throughput and latency.

 

Figura A - DRNet ray tracing simulations and measurements campaign in Turin – November 2018

In this framework, the capability of simulating mobile coverage, either for 4G and 5G networks, is a fundamental brick for the design of “drone ready” wireless networks. Thanks to proprietary IRT (Intelligent Ray Tracing) models, TIM is pioneering this field, exploiting advanced tools for the prediction of aerial coverage in connected drones scenario (3GPP UAV propagation models).
Ad hoc measurement campaigns were performed to validate and tune the UAV models in various propagation scenarios, focusing on urban areas where drones operations are more challenging. Good agreement between measurements and simulation was experimented.
On the other hand, Interference analysis identified some potential issues in case of massive connected-UAV’s scenario: significant uplink interference increase for “mobile ground users”, due to drone-to-ground transmissions impacting over wide areas.
For such a reason, overall network performance analysis focused on aerial users (e.g. in terms of up-link and down-link user throughput estimation) has to be carried out, exploiting both simulations and measurements, including MDT (Minimization of Drive Tests) features, able to collect geo-referenced measurements directly form the drones. Active antennas will play an important role in this context, with the possibility of automatically generating specific beams directed towards aerial users.
The above summarized process was efficiently applied on a RT HD Environmental Monitoring UAV demo, into the framework of Liguria Digitale, as proof-of-concept for the incoming 5G use cases applicable in the future smart cities. Coverages and throughput maps both at ground and aerial levels were provided for preliminary feasibility study and localization of demo trial site.

 

Figura B - Liguria Digitale feasibility study and simulations: best server and throughput map @ 30 m a.g.l – May 2019

 

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