Preliminary 4.5G Cellular Network Assessment with Calibrated Standard Propagation Model (SPM) for uTM-UAS Operations in Singapore Airspace

The advantages of nationwide coverage, secured mobile connectivity, licensed spectrum operations, interference mitigation and mobility robustness capabilities, LTE Advanced Pro (4.5G) cellular network is a highly suitable candidate for Unmanned Aerial Systems (UAS) Command and Control (C2) communication management within Urban Traffic Management of Unmanned Aerial Systems (uTM-UAS) that have been presented at the Drone Enable International Civil Aviation Organization's UAS Industry Symposium. In this paper, coverage and performance assessment for sub-urban, urban and coastal areas in Singapore for up to 400 feet (121.92 metre) altitude is first performed. Utilizing the collected measurements with Atoll radio planning tool, a calibrated Standard Propagation Model (SPM) is proposed to simulate 4.5G coverage availability for entire Singapore airspace up to 400 feet altitude. This calibrated SPM considers pathloss correction due to angular-depression between UAS' altitude and cell tower height to improve coverage prediction accuracy. The accuracy of less than 8dB error in variance between simulation and experimental results have been achieved. The calibrated model will be used to support the uTM-UAS to indicate suitable airspace in terms of communication coverage and performance to ensure safe UAS operations.