Channel Access Deterrence Attack: An Attack Against Spectrum Coexistence Between NR-U and Wi-Fi in the 5 GHz Band

Listen-Before- Talk-based channel access mechanisms have been crucial to enabling coexistence between cellular technologies (e.g., 4G and 5G) and Wi-Fi in the 5 GHz band. Though the coexistence between cellular and Wi-Fi technologies garnered significant research regarding interference and fairness, security issues have long been overlooked. This paper introduces a novel attack strategy, namely the Channel Access Deterrence attack, that takes advantage of an inherent vulnerability in the channel access mechanism of cellular technologies (e.g., 5G NR-U), whereby small interference signals are strategically transmitted to thwart the cellular base station from accessing the channel. This paper introduces a Markov Chain-based model to embody this attack's impact on cellular technologies and Wi-Fi; this model helps to understand and assess the channel access vulnerabilities in such coexistence scenarios. In addition, this paper proposes a resilience mechanism during channel access to mitigate such threats and evaluates the system's performance in various scenarios. To the extent of our knowledge, this research is the first to introduce such a threat and to provide a novel security perspective when designing spectrum coexistence mechanisms.