Physical Layer Modulation Scheme And Data Encryption Protection Algorithm

With wireless communication developing towards the new trend of broadband communication, higher level of communication speed, transmission service type and system security are required. To meet the safety demands of the next generation wireless communication system, conventional security mechanisms which work at link layer or higher are considered unable to protect the air interface and modulation mode, which brings about security threats for wireless systems. Therefore, the study of wireless physical layer security is necessary, while protecting the modulation related information and air interface is particularly important.OFDM modulation system is chosen as the background in this paper, and after the study on security threats of communication system and the research status of physical layer security mechanisms, two physical layer security algorithms are proposed based on previous studies. A diagonal key matrix is used to encrypt the symbols after IFFT in the modulation protection algorithm based on diagonal key matrix, in order to achieve constellation disruption. And typical modulation recognition methods are adopted to verify the protection effect of the proposed algorithm. Theoretical analysis and simulation results show that the algorithm can effectively resist typical modulation recognition with no impact on system inherent performance. Another physical layer modulation and data protection algorithm based on manual noise consists of two encryption steps, which are constellation disruption and manual noise signal superposition. Theoretical analysis and simulation results show that the proposed algorithm can protect both the inlet and outlet of OFDM data and has considerable security performance and the manual noise cannot be deleted, while the algorithm can also achieve data and modulation protection without changing the system inherent performance, which makes the modulation recognition rate reduced significantly at illegal receivers.