Multilevel coding using trellis-coded modulation and reed-solomon codes

Receiver apparatus for processing a received signal that was generated by applying first and second data streams to a trellis encoder and a Reed-Solomon encoder, respectively, to provide first and second encoder output streams, respectively, and by thereafter providing, in said generated signal, a sequence of channel symbols having a trellis distance and being selected from a predetermined 2N-dimensional signal constellation based on a rectangular lattice, N being an integer, said signal constellation comprising a plurality of subsets of channel symbols separated by a predetermined distance, which is less than said trellis distance, said channel symbols being selected in response to said first and second encoder output streams, said receiver apparatus comprising

• means including a maximum likelihood decoder for recovering from said received signal a) said first data stream and b) said second encoder output stream,
• a Reed-Solomon decoder, and
• means for applying said recovered second encoder output stream to said Reed-Solomon decoder to recover said second data stream.