I. Introduction
Bit-interleaved coded modulation (BICM) is a flexible modulation/coding scheme which allows the designer to choose a modulation constellation independently of the coding rate [1] [2]. In BICM, the output of the channel encoder and the input to the modulator are separated by a (pseudo-)random bit-level interleaver. At the receiver's side, the reliability metrics for the coded bits are calculated according to the maximum likelihood principle. These logarithmic likelihood ratios (LLR), or simply -values, are then deinterleaved and further used by the soft-input channel decoder.