LPD-Aware 5G NR Downlink Synchronization for Tactical Networks

Communication technologies play a crucial role in battlefields. They are an inalienable part of any tactical response, whether at the battlefront or inland. Such scenarios require that the communication technologies be versatile, scalable, cost-effective, and stealthy. While multiple studies and past products have tried to address these requirements, none of them have been able to solve all the four challenges simultaneously. Hence, in this paper, we propose a tactical solution that is based on the versatile, scalable, and cost effective 5G NR system. We investigate the stealthiness of this solution by evaluating the probability with which an adversary is able to detect the tactical communication. Particularly, we focus on the probability of detection in the initial-access phase where, by means of simulations, we show that this probability is close to 100%, suggesting that 5G out-of-the-box is not suitable for a tactical network. To address this issue, we propose a novel approach that involves some modifications to the initial-access procedure, particularly user-equipment (UE)-first initial access, that lowers the probability of detection while not requiring any modifications to the UE chipset implementation. We then propose utilizing downlink power control and the uplink channel-state-information-based beamforming to lower the eavesdropper detection probability while not compromising the performance of the legitimate tactical UE. This paper was originally presented at the NATO Science and Technology Organization Symposium (ICMCIS) organized by the Information Systems Technology (IST) Scientific and Technical Committee, IST-209-RSY - the ICMCIS, held in Oeiras, Portugal, 13–14 May 2025.