Securing Cognitive Radio Networks During Cooperative Spectrum Access Using Game Theory

Cognitive radio has become one of the most promising technology and probable solution for the shortage of spectrum. This paper deals with a different class of security problem, where multiple half-duplex secondary users independently eavesdrop the communication of primary users, unless given access to communicate over the same spectrum band. Primary Station (PS) needs to characterize the optimal rule to grant spectrum access to selected secondary users. Granting spectrum access to selected Eavesdropping Secondary User (ESU) helps in improving the rate of uneavesdropped messages to the PS, i.e., primary secure rate, as transmission from secondary user interferes with the eavesdropping signal from other ESUs. The proposed method uses reverse Stackelberg game theory for the selection of an ESU by the PS to increase the utility when multiple ESUs exist. This method emphasizes on the utility as well as security of the PS. Channel gains provided by the ESUs are authenticated. PS can grant access to any authentic ESU even if its the strongest eavesdropper. The main criteria for selection of ESU is based on the utility and net secure rate of primary user (PU). Results show improved utility and net secure rate of the PU.