Security Gap Improvement of BICM Systems Through Bit-Labeling Optimization for the Gaussian Wiretap Channel

In this paper, we investigate the impact of a bit-labeling scheme on security performance bit-interleaved coded modulation (BICM) systems for Gaussian wiretap channel, where concept gap plays an important role. To exemplify this, present optimization algorithms bit-labeling, difference achievable information rates (AIRs) legitimate receiver and eavesdropper is maximized. Our results demonstrate that conventional Gray labeling may not be necessarily optimal in terms gap, proposed can significantly improve its at cost degradation bit-error rate (BER) by receiver. We also that, high order quadrature amplitude (QAM), such as 64QAM, dimension-wise sufficient to achieve similar direct two-dimensional optimization. The approach combined with state-of-the-art coding schemes further reduce gap.