A study of 5G New Radio and its vulnerability to jamming

Information and communication technology (ICT) is a critical factor needed by the Norwegian Armed Forces to succeed in their missions. Over the coming years, the Norwegian defence sector will invest heavily in new combat-near ICT solutions. Technologies developed for the civilian market are expected to be an integral part of this investment. Commercial mobile technology is a technology that is developed for the commercial market and has gathered interest in the military worldwide as a cost-effective alternative to cover some of the military needs for communication services. The latest fifth generation of mobile communications (5G) can benefit the military in several domains, including radio communication. The 5G radio interface, called New Radio (NR), provides high transmission speeds and introduces some novelties like multi-antenna operation on high frequencies. However, a commercial technology like 5G NR is not explicitly designed to meet the military requirements for robustness. There is a lack of information on how well 5G NR performs when exposed to electronic warfare such as radio jamming. Insights into the effect of jamming are needed to assess operational scenarios in which 5G is safe for military use. This report documents a study of the threat of radio jamming on the 5G NR. We introduce the necessary background on 5G NR. Then, we discuss 5G NR vulnerabilities to jamming based on theory and literature, but none of these previous studies have examined the effect of jamming on a complete and real-life 5G NR system. Therefore, we conducted a jamming experiment, creating a realistic scenario where a custom-made jammer aimed to disrupt a commercial 5G NR system that consisted of an off-the-shelf smartphone and a commercial base station antenna operating on the 3.6 GHz frequency band. The experiment showed that the uplink signal was the most vulnerable part of the radio communication, primarily because of the limited transmit power at the user terminal. The 5G radio system adapted to moderate jamming by lowering the modulation and coding scheme. However, in some cases, the 5G radio system struggled to find the optimal parameters. When the jamming signal was too strong, the 5G connection was terminated. We identified a threshold (breaking point) at which a jamming signal was too strong for the 5G NR system to work. By combining our experimental results with theoretical propagation models, we developed a model that estimates the distance between a jammer and a base station and the jammer output power an adversary needs for a successful jamming attack. The model can help evaluate the threat level and decide whether or not 5G NR is suitable for a given military scenario. We identified several practical mitigation measures that might make the 5G radio communication, especially the uplink transmission, more robust against radio jamming. Future studies should further investigate the implementation aspects of these jamming mitigation measures in the military use of 5G.