Method and apparatus for encoding/decoding QAM trellis coded data

An apparatus for decoding Quadrature Amplitude Modulation (QAM) trellis coded data comprising:

• decoder means for receiving information relating to signal space coordinates of a received signal and decoding said signal space information according to a predetermined trellis decoding format based upon a punctured convolutional encoding format to provide an estimate of a subset of bits represented by said received signal;
• sector means for receiving said signal information and for providing a sector number in accordance with said signal information and a predefined mapping function, said sector number corresponding to said signal space information indicative of a predefined area in the signal space plane in the proximity of said signal space coordinates;
• encoder means for receiving said estimated subset of bits and encoding said subset of bits according to a punctured convolutional encoding format based upon a lower rate convolutional encoding format to provide a plurality of encoded symbols;
• and
• decision means for receiving said sector number and said encoded symbols and providing an estimate of remaining uncoded bits represented by said received signal in accordance with a predetermined decision format.