Enforcing spectrum access rules in cognitive radio networks through cooperative jamming

In Cognitive Radio Networks (CRNs) with dynamic spectrum access, it is of paramount importance to ensure the spectrum access rules are honestly followed by each secondary user. Existing approaches either require significant modifications to the system hardware, or can only deter the spectrum abuse from happening by punishing abusers after-the-fact, which is ineffective in reality as there lacks universal identification for each device. In this paper, we propose a novel spectrum access rule enforcing scheme by introducing a "spectrum guardian", who punishes abusers immediately on-the-scene through optimally jamming their signals using multiple antennas while without affecting the communication between primary users, thus removing abusers' incentive to exploit the spectrum for their own benefit. Our scheme requires no modifications to Commercial-Off-The-Shelf (COTS) CR devices, nor the need of device identification.