A Partially Coupled LDPC Coded Scheme for the Gaussian Wiretap Channel

Abstract

In this letter, we propose an effective partially coupled low-density parity-check coded scheme to reduce the security gap for the Gaussian wiretap channel. In our scheme, codewords are partially coupled by exclusive OR adding the message bits from a codeword to the parity check bits from its consecutive codeword. An iterative decoding algorithm is also proposed to utilize the correlations between codewords. Based on this design, error propagation effect between codewords is achieved to worsen the performance at the eavesdropper, which receives messages via a poor conditioned channel. Numerical results demonstrate that the proposed scheme outperforms the punctured scheme in terms of the equivocation rate and the security gap.