UC San Diego

Cognitive radio (CR), which employs spectrum sensing technology to realize the spectrum reuse, holds much promise as a technology that will play a significant role in communication systems of the future. The utilization efficiency of spectrum has been improved by allowing for dynamic accessing. However, the sensing before accessing strategy makes a CR network more vulnerable to an intelligent adversary attack. In addition to jamming as in traditional radio systems, the adversary can launch signals to the unused bands to spoof the secondary users in a CR network. In the first scenario, an optimal spoofing strategy subject to the adversary's power constraint is briefly introduced. The simulation results match well to numerical results in [15], where the worst- case deception strategy is shown to be equal-power, partial-band spoofing. In the secondary scenario, the tradeoff between spoofing and jamming a CR network by an intelligent adversary with the presence of primary users is analyzed. Considering an energy constraint, the intelligent adversary negotiates the energy distribution between jamming primary users, and spoofing and/or jamming secondary users to minimize the system average throughput. It is shown that in a cluster-based CR network, once the secondary users require a relatively large fraction of the allowable bands, spoofing is more efficient than jamming the secondary users in terms of minimizing the throughput of the secondary users. Jamming the primary users can always decrease the throughput of the primary users