Research And Design Of COFDM Security System Based On Secrecy Coding Of Security Gap

With the wide application of 4G technology and the continuous advancement of 5G and 6G technologies,wireless communication networks has gone to broadband and integrated,and has become an important dual-use infrastructure for both military and civilian.However,the communication security is increasingly challenged.In order to resist various security threats caused by open wireless links and effectively prevent eavesdropping,the physical layer security method without the key based on physical channel randomness was proposed.At present,this method has become a research hotspot in the field of wireless communication security.Among them,the realization of communication security by reducing the security gap is an important research direction of the physical layer security.Firstly,the implementation of the ideal security gap(0dB)under the Gaussian without feedback eavesdropping channel model.It is proved that the perfect scrambling can be asymptotically achieved,and under the binary modulation and multiple modulation,it proves that the ideal security gap can be asymptotically achieved with the increase of the size of perfect scrambling matrix.Secondly,combining the perfect scrambling with the different secrecy coding schemes that can reduce the security gap,and simulation analyzes the impact of different secrecy codings on the security gap,according to the simulation results,a new secrecy coding scheme which combining perfect scrambling,first-order differential coding,EG-LDPC coding and Yarg mapping was designed.This new secrecy coding scheme can achieve lower security gap than other secrecy coding schemes.Finally,this secrecy coding scheme is applied to COFDM system,a COFDM security system scheme based on secrecy coding of security gap was designed,and the security gap of the scheme was simulation analysis under the Gaussian channel and multipath channel.The simulation results show that this security system scheme can be realized close to 0 dB securitygap under the Gaussian channel,and achieve 1.6 dB security gap under multipath channel,has a good security.