High-Security Chaotic Cognitive Radio System With Subcarrier Shifting

Chaotic sequences have been applied to cognitive radio (CR) systems to enhance the system security. However, since the chaotic maps are publicly known, attackers may derive the key parameters of chaotic sequences, then finally retrieve the information. In this paper, we present a new subcarrier-shifting based chaotic cognitive radio (SSCCR) scheme for improving the security mechanism of chaotic cognitive radio (CCR) systems. More specifically, we propose to transmit the information with the chaos-subcarrier pair by combining the chaotic sequence with available subcarriers, where the chaos-subcarrier pairs dynamically change with shifted subcarriers. The subcarrier shifting rule is determined by another chaotic sequence for security enhancement. With the developed mathematical model, we analytically derive its bit error rate (BER) formula. Simulation results are compared to verify the effectiveness of our derivations, and the information leakages of SSCCR and CCR systems are studied. It is demonstrated that the proposed SSCCR system offers a high security and the malicious attackers can not retrieve the transmitted information even if they get the key chaos parameters.