A channel matched design of LDPC based secrecy coding for the fast fading channel

In this paper, we focus on security problem of low density parity check (LDPC) codes design in Rayleigh fading channel. In our secrecy coding scheme, confidential message bits are first interleaved according to the fading coefficients of authorized channel to hide positions, and then replaced with random dummy bits to conceal information from potential eavesdroppers. Simulation results show that due to different feature of authorized and eavesdropper´s channels, the proposed scheme ensures that the authorized receiver is able to reconstruct the confidential message, while the eavesdropper almost can not extract any information with the same transmit power. Furthermore, the security gap can be further reduced.