BLOCK-CODED MODULATION USING REED-MULLER COMPONENT CODES AND MULTISTAGE DECODING

Using a 2-step partitioning of the signal constellation and Reed-Mulle r component codes, we construct block-coded modulation (BCM) schemes t hat achieve an asymptotic coding gain close to 6 dB. The component cod e associated to the first partitioning step is a distance-4 or a dista nce-8 Reed-Muller code, and the code associated to the second partitio ning step is a simple parity-check code. We investigate BCM schemes wi th square signal constellations and a fractional number of information bits per symbol as well as BCM schemes with circular signal constella tions and an integer number of information bits per symbol. We use mul tistage decoding with a Viterbi algorithm for the first component code using the trellis description given by Forney. Our results indicate t hat with short block lengths, these BCM schemes compare favorably with trellis coded modulation (TCM) of similar complexity. Due to the rapi d increase of the error coefficient, however, they lose their advantag e as the block length increases.