Improved information rates for bit-interleaved coded modulation

This paper shows that bit-interleaved coded modulation (BICM) over the Gaussian channel can achieve information rates larger than the so-called BICM capacity. For some labelings the improvement with respect to the BICM capacity is significant, especially at low and medium signal-to-noise ratios (SNR). Specifically, natural binary labeling is found to be both first- and second-order optimal at low SNR.