COMPUTING ERROR PROBABILITIES OF MULTILEVEL MODULATION CODES

We describe a computational algorithm for the evaluation of error prob abilities of multilevel modulation codes. This is based on the derivat ion of a trellis cataloging the words of the component codes and of a suitable set of branch labels depending on the channel on which the tr ansmission takes place (additive white Gaussian noise channel, fading channel with or without channel state information). The error probabil ity is upper bounded by the transfer function of this trellis, which i s derived in closed form.