Efficient optimal soft-decision decoding for multilevel block modulation codes

The multistage trellis decoding method is examined when applied to multilevel block modulation codes. It is shown how low decoding complexity can be achieved using this method, while performing maximum-likelihood decoding. As the decoding complexity involved is shown to be channel-quality dependent, the actual decoding computational burden becomes very low when the system signal-to-noise ratio is high. A way of constructing the generator matrix for multilevel block modulation codes is demonstrated, in order to build a proper trellis for decoding