Pragmatic trellis-coded modulation system and method therefor

A method for pragmatic trellis-code modulating a communications signal to produce a polar amplitude phase-shift keyed (P-APSK) quadrature signal communicating at a data rate of at least four symbols per unit interval of time, said method comprising the steps of:

• a) parsing information bits within said signal into, per unit interval of time, at least two uncoded information bits and at least one to-be-coded information bit;
• b) encoding, within a convolutional encoder, said to-be-coded information bits into two encoded information bits per to-be-coded information bit;
• c) accepting, into a P-APSK mapping circuit, N-2 of said uncoded information bits per unit interval of time where N is an integer number;
• d) accepting, into said P-APSK mapping circuit, two of said encoded information bits per unit interval of time;
• e) mapping said accepted uncoded and encoded information bits to a mapped phase point, said mapped phase point being one phase point within a constellation having 2.sup.N of said phase points arranged in at least two concentric rings, the outermost pair of which possesses a like predetermined number of phase points per ring;
• and
• f) obtaining, from said P-APSK mapping circuit, said quadrature signal defining said mapped phase point.

A pragmatic trellis-coded modulator comprising:

• a parsing circuit configured to parse input information bits into uncoded information bits and to-be-coded information bits;
• a convolutional encoding circuit coupled to said parsing circuit and configured to produce at least two encoded information bits for each to-be-coded information bit processed therein per unit interval of time;
• and
• a polar amplitude phase shift keyed (P-APSK) mapping circuit coupled to said parsing circuit and said convolutional encoding circuit and configured to:
• accept an integer number "N" of said information bits per unit interval of time, N-2 of which are said uncoded information bits and two of which are said encoded information bits;
• map said accepted uncoded and encoded information bits to a mapped phase point, said mapped phase point being one phase point within a constellation having 2.sup.N of said phase points arranged in at least two concentric rings, the outermost pair of which possesses a like predetermined number of phase points per ring;
• associate each of said 2.sup.N phase points with a data value for said encoded information bits;
• position said 2.sup.N phase points upon said concentric rings so that said encoded-information-bit data values for any two adjacent phase points upon each of said rings are mutually inverse;
• and
• provide a quadrature signal defining said mapped phase point.