Physical Layer Security for OFDM Wireless Communications

Through studying existing physical layer security algorithms for wireless communication systems this paper analyzes the security requirements of OFDM systems and identifies opportunities for data encryption at the system input and protection at the channel output. First a physical layer security algorithm based on phase rotation and key matrices was designed thoroughly examining its security and feasibility. Subsequently integrating artificial noise into the physical layer a further physical layer security algorithm based on artificial noise and key matrices is proposed. This approach combines phase rotation and key matrix encryption with the addition of artificial noise signals to conceal the encrypted OFDM signals thereby achieving modulation scheme protection for transmitted signals and secure communication between authorized users. Current wireless communication systems face increasingly severe challenges in information security. Existing traditional security mechanisms rely on mathematical problems and the massive computational demands coupled with highly complex encryption/decryption algorithms have long overwhelmed communication devices.