5G-Based Synchronous Network for Air Traffic Monitoring in Urban Air Mobility

In the next decade, Urban Air Mobility (UAM) is expected to become a global reality. Its success hinges on the realization of infrastructures for air traffic control and management (ATM) to guarantee security and safety in mobility scenarios including thousands of flying drones and aircraft operating at low heights and crossing paths while adhering to designated clearance zones around buildings. For the ATM system to effectively manage and control air traffic, real time tracking of the positions of flying objects is essential. This paper aims to propose and discuss the architecture key functionalities of a dedicated communication system designed for periodic transmission of position messages from drones and aircraft to the ATM. This system leverages on synchronous 5G technology, utilizing negative numerology to enable very narrow-band transmissions. The paper analyzes the main challenges associated with the planning of this system including its capacity to serve a specific number of drones and aircraft for fixed allocated bandwidth. It is shown that, depending on the achievable minimum modulation and coding scheme in the flying area, the system can serve thousands of drones/aircraft per assigned bandwidth of 20 MHz. Additionally, we discuss a scheme for the OFDMA receiver at the radio unit (RU) able to estimate and compensate for frequency differences among drones/aircraft signals received at the same RU. We have analyzed its performance in terms of the achievable un-coded bit error probability for variable modulation format.