In cognitive radio systems, primary user emulation (PUE) attack means that an attacker sends primary-user-like signals during the spectrum sensing period such that honest secondary users leave the corresponding channels, which causes a serious threat to cognitive radio systems. A passive anti-PUE approach, similar to the random frequency hopping in traditional anti-jamming schemes, is proposed and called dogfight in spectrum. In this scheme, the defenders randomly choose channels to sense and avoid the PUE attack. It is assumed that the channel statistics like availability probabilities are known; then the PUE attack and the random hopping are modeled as a zero-sum game between the attacker and defending secondary user(s). The Nash equilibrium of the game is found. The anti-jamming efficiency is also obtained. Numerical simulations demonstrated the performances of the proposed schemes for both the single defender, multiple defender and multiple round cases.
['Husheng Li', 'Zhu Han']
Dogfight in Spectrum: Combating Primary User Emulation Attacks in Cognitive Radio Systems—Part II: Unknown Channel Statistics