SDR-Based 5G NR C-Band I/Q Monitoring and Surveillance in Urban Area Using a Helikite

In this paper, we report experimental results in collecting and processing 5G NR I/Q samples in the 3.7 GHz C-band by using a software-defined radio (SDR)-mounted helikite. We use MATLAB's 5G toolbox to post-process the collected data, to obtain the synchronization signal block (SSB) from the I/Q samples, and then go through the cell search, synchronization procedures, and reference signal received power (RSRP) and reference signal received quality (RSRQ) calculation. We plot these performance metrics for various physical cell identities as a function of the helikite's altitude. Furthermore, building on our experience with the collected and post-processed data, we discuss potential vulnerabilities and challenges for the 5G NR systems to surveillance, spectrum coexistence with existing services, jammina attacks, and post-quantum era attacks.