Data communication system and method therefor

Claim 3

A decoding apparatus as claimed in claim 1 wherein: said convolutionally encoded data stream is received throughout a multiplicity of unit intervals, puncturing does not occur in a first portion of said unit intervals, and puncturing does occur in a second portion of said unit intervals; said apparatus additionally comprises a first branch metric processor configured to generate branch metrics for use by said convolutional decoder during said first portion of said unit intervals, said first branch metric processor being responsive to said phase estimate values; and said depuncture circuit comprises a second branch metric processor configured to generate branch metrics for use by said convolutional decoder during said second portion of said unit intervals, said second branch metric processor being responsive to said phase estimate values.

Claim 4

A decoding apparatus as claimed in claim 2 wherein: said first branch metric processor supplies two unpunctured likelihood values to said convolutional decoder for each phase estimate value to which said first branch metric processor responds; and said second branch metric processor is configured to provide a first likelihood value and a duplicate of said first likelihood value to said convolutional decoder for each phase estimate value to which said second branch metric processor responds.

Claim 5

A decoding apparatus as claimed in claim 3 wherein said second branch metric processor is configured to provide a second likelihood value and a duplicate of said second likelihood value to said convolutional decoder for each phase estimate value to which said second branch metric processor responds.

Claim 6

A decoding apparatus as claimed in claim 4 wherein: said second branch metric processor is further configured to supply a third likelihood value and a duplicate of said third likelihood value to said convolutional decoder so that said first likelihood value and duplicate are routed to first and second inputs of said convolutional decoder for each phase estimate value to which said second branch metric processor responds, and so that said third likelihood value and duplicate are routed to third and fourth inputs of said convolutional decoder for each phase estimate value to which said second branch metric processor responds; said second branch metric processor is further configured to supply a fourth likelihood value and a duplicate of said fourth likelihood value to said convolutional decoder so that said second likelihood value and duplicate are routed to said first and third inputs of said convolutional decoder for each phase estimate value to which said second branch metric processor responds, and so that said fourth likelihood value and duplicate are routed to said second and fourth inputs of said convolutional decoder for each phase estimate value to which said second branch metric processor responds; and said first branch metric processor supplies fifth, sixth, seventh, and eighth likelihood values to said first, second, third, and fourth inputs of said convolutional decoder for each phase estimate value to which said first branch metric processor responds.

Claim 7

A decoding apparatus as claimed in claim 2 wherein: each phase estimate value conveys first and second convolutionally encoded symbols; for one of said phase estimate values, said second branch metric processor generates a value describing the likelihood that said first symbol exhibits a predetermined polarity; and said second branch metric processor is configured so that said second branch metric processor likelihood value is compensated to null out influence of said second symbol.

Claim 8

A decoding apparatus as claimed in claim 6 wherein: said first branch metric processor generates a value describing the likelihood that said first symbol exhibits said predetermined polarity; and said first branch metric processor is configured so that said first branch metric processor likelihood value is influenced by said second symbol.

Claim 9

A decoding apparatus as claimed in claim 6 wherein: said likelihood value approximately equals an average of a first chance value and a second chance value; said first chance value represents the likelihood that said first symbol exhibits said predetermined polarity given said one phase estimate value and assuming a priori knowledge that said second symbol exhibits said predetermined polarity; and said second chance value represents the likelihood that said first symbol exhibits said predetermined polarity given said one phase estimate value and assuming a priori knowledge that said second symbol exhibits a polarity opposite to said predetermined polarity.

Claim 10

A decoding apparatus as claimed in claim 6 wherein: for said one phase estimate value, said second branch metric processor generates a value describing the likelihood that said second symbol exhibits said predetermined polarity; and said second branch metric processor is configured so that said second symbol likelihood value is compensated to null out influence of said first symbol.

Claim 11

A decoding apparatus as claimed in claim 9 wherein: said first symbol likelihood value approximately equals an average of a first chance value and a second chance value; said first chance value represents the likelihood that said first symbol exhibits said predetermined polarity given said one phase estimate value and assuming a priori knowledge that said second symbol exhibits said predetermined polarity; said second chance value represents the likelihood that said first symbol exhibits said predetermined polarity given said one phase estimate value and assuming a priori knowledge that said second symbol exhibits a polarity opposite to said predetermined polarity; said second symbol likelihood value approximately equals an average of a third chance value and a fourth chance value; said third chance value represents the likelihood that said second symbol exhibits said predetermined polarity given said one phase estimate value and assuming a priori knowledge that said first symbol exhibits said predetermined polarity; and said fourth chance value represents the likelihood that said second symbol exhibits said predetermined polarity given said one phase estimate value and assuming a priori knowledge that said first symbol exhibits a polarity opposite to said predetermined polarity.

Claim 12

A decoding apparatus as claimed in claim 1 wherein said depuncture circuit comprises a memory element configured to be downloaded with different data sets, said different data sets being configured to control depuncturing for different code rates.

Claim 13

A decoding apparatus as claimed in claim 1 wherein: said data stream is configured in accordance with a polar amplitude phase shift keyed (P-APSK), pragmatic trellis coded modulation (PTCM) scheme; said convolutional decoder is configured to provide a second stream of data estimates; said decoding apparatus additionally comprises a convolutional encoder adapted to encode said second stream of data estimates to produce a re-encoded bit stream; and said decoding apparatus additionally comprises a slicer configured to form a first stream of data estimates in response to said re-encoded bit stream and said phase estimate values.

Claim 14

A decoding apparatus as claimed in claim 1 wherein: said data stream is configured in accordance with a polar amplitude phase shift keyed (P-APSK) modulation scheme; said phase estimate values convey quadrature phase and magnitude data; and said decoding apparatus additionally comprises a carrier phase recovery loop having an input coupled to said phase estimator and being configured to adjust said quadrature phase data in response to said quadrature magnitude data to generate a phase-adjusted signal, said phase-adjusted signal being used for carrier tracking.

Claim 17

A method as claimed in claim 14 wherein: said convolutionally encoded data stream is received throughout a multiplicity of unit intervals, puncturing does not occur in a first portion of said unit intervals, and puncturing does occur in a second portion of said unit intervals; said method additionally comprises the step of generating first branch metrics for use in said decoding step during unit intervals where puncturing does not occur, said first branch metrics being responsive to said phase estimate values; and said erasure value producing step comprises the step of generating second branch metrics for use in said decoding step during unit intervals where puncturing does occur, said second branch metrics being responsive to said phase estimate values.

Claim 18

A method as claimed in claim 15 wherein: said first branch metric generating step generates two likelihood values for each phase estimate value to which said first branch metric generating step responds; and said second branch metric generating step generates a first likelihood value and a duplicate of said first likelihood value for each phase estimate value to which said second branch metric generating step responds.

Claim 19

A method as claimed in claim 16 wherein said second branch metric generating step comprises the step of providing a second likelihood value and a duplicate of said second likelihood value for each phase estimate value to which said second branch metric generating step responds.

Claim 20

A method as claimed in claim 17 wherein: said decoding step is performed in a convolutional decoder having first, second, third, and fourth inputs; said second branch metric generating step comprises the step of supplying a third likelihood value and a duplicate of said third likelihood value so that said first likelihood value and duplicate are routed to said first and second inputs of said convolutional decoder, and so that said third likelihood value and duplicate are routed to said third and fourth inputs of said convolutional decoder; said second branch metric generating step additionally comprises the step of supplying a fourth likelihood value and a duplicate of said fourth likelihood value so that said second likelihood value and duplicate are routed to said first and third inputs of said convolutional decoder and so that said fourth likelihood value and duplicate are routed to said second and fourth inputs of said convolutional decoder; and said first branch metric generating step comprises the step of supplying fifth, sixth, seventh, and eighth likelihood values to said first, second, third, and fourth inputs of said convolutional decoder for each phase estimate value to which said first branch metric generating step responds.

Claim 21

A method as claimed in claim 15 wherein: each phase estimate value conveys first and second convolutionally encoded symbols; for one of said phase estimate values, said second branch metric generating step generates a value describing the likelihood that said first symbol exhibits a predetermined polarity; and said second branch metric generating step comprises the step of compensating said first symbol likelihood value to null out influence of said second symbol.

Claim 22

A method as claimed in claim 19 wherein: said first branch metric generating step generates a value describing the likelihood that said first symbol exhibits said predetermined polarity; and said first branch metric generating step is configured so that said first branch metric likelihood value is influenced by said second symbol.

Claim 23

A method as claimed in claim 19 wherein: said likelihood value approximately equals an average of a first chance value and a second chance value; said first chance value represents the likelihood that said first symbol exhibits said predetermined polarity given said one phase estimate value and assuming a priori knowledge that said second symbol exhibits said predetermined polarity; and said second chance value represents the likelihood that said first symbol exhibits said predetermined polarity given said one phase estimate value and assuming a priori knowledge that said second symbol exhibits a polarity opposite to said predetermined polarity.

Claim 24

A method as claimed in claim 19 wherein: for said one phase estimate value, said second branch metric generating step generates a value describing the likelihood that said second symbol exhibits said predetermined polarity; and said second branch metric generating step comprises the step of compensating said second symbol likelihood value to null out influence of said first symbol.

Claim 25

A method as claimed in claim 22 wherein: said first symbol likelihood value approximately equals an average of a first chance value and a second chance value; said first chance value represents the likelihood that said first symbol exhibits said predetermined polarity given said one phase estimate value and assuming a priori knowledge that said second symbol exhibits said predetermined polarity; said second chance value represents the likelihood that said first symbol exhibits said predetermined polarity given said one phase estimate value and assuming a priori knowledge that said second symbol exhibits a polarity opposite to said predetermined polarity; said second symbol likelihood value approximately equals an average of a third chance value and a fourth chance value; said third chance value represents the likelihood that said second symbol exhibits said predetermined polarity given said one phase estimate value and assuming a priori knowledge that said first symbol exhibits said predetermined polarity; and said fourth chance value represents the likelihood that said second symbol exhibits said predetermined polarity given said one phase estimate value and assuming a priori knowledge that said first symbol exhibits a polarity opposite to said predetermined polarity.

Claim 26

A method as claimed in claim 14 wherein: said erasure value producing step is performed in a programmable depuncture circuit; and said method additionally comprises the step of programming said depuncture circuit with different data sets, said different data sets being configured to control depuncturing for different code rates.

Claim 27

A method as claimed in claim 14 wherein: said data stream is configured in accordance with a pragmatic trellis coded modulation (PTCM) scheme; said decoding step provides a second stream of data estimates; said method additionally comprises the step of convolutionally encoding said second stream of data estimates to produce a re-encoded bit stream; and said method additionally comprises the step of forming a first stream of data estimates in response to said re-encoded bit stream and said phase estimate values.

Claim 28

A method as claimed in claim 25 wherein said forming step comprises the step of decoding a polar amplitude phase shift keyed (P-APSK) modulation.

Claim 29

A method as claimed in claim 26 wherein said phase estimate values convey quadrature phase and magnitude data, and said method additionally comprises the step of: operating a carrier phase recovery loop configured to adjust said quadrature phase data in response to said quadrature magnitude data to generate a phase-adjusted signal, said phase-adjusted signal being used for carrier tracking.

Claim 30

A method as claimed in claim 26 wherein said pragmatic trellis coded modulation scheme is amplitude phase shift keyed (APSK) modulation, said phase estimate values convey quadrature phase and magnitude for each unit interval, and said method additionally comprises the step of: adjusting said quadrature phase in response to said quadrature magnitude to generate a phase-adjusted signal; and controlling a carrier tracking loop in response to said phase-adjusted signal.

Claim 31

A method as claimed in claim 25 wherein said forming step comprises the step of addressing a memory element with said phase estimate values and said re-encoded bit stream.

Claim 32

A method as claimed in claim 25 wherein said PTCM scheme is rotationally invariant, and said method additionally comprises the steps of: differentially decoding said first stream of data estimates; and differentially decoding said second stream of data estimates.

Claim 33

A programmable apparatus for decoding information bits communicated at a variety of data rates using a pragmatic modulation scheme that applies a primary modulation to a first portion of said information bits, convolutional encoding to a second portion of said information bits to generate an encoded bit stream, and a secondary modulation to said encoded bit stream, said apparatus comprising: a phase estimator configured to generate a phase estimate stream having a phase estimate value for each unit interval; a convolutional decoder coupled to said phase estimator, said convolutional decoder being configured to receive and decode said phase estimate values to produce a decoded data stream that corresponds to said second portion of said information bits; a convolutional encoder coupled to said convolutional decoder to generate a re-encoded bit stream; and a demodulation look-up table coupled to said phase estimator and to said convolutional encoder, said table being configured to generate hard data estimates which correspond to said first portion of said information bits in response to said phase estimate values and said re-encoded bit stream.

Claim 34

A programmable apparatus for decoding information bits communicated at a variety of data rates using a pragmatic modulation scheme that applies a primary modulation to a first portion of said information bits, convolutional encoding to a second portion of said information bits to generate an encoded bit stream, and a secondary modulation to said encoded bit stream, said apparatus comprising: a phase estimator configured to generate a phase estimate stream having a phase estimate value for each unit interval; a convolutional decoder coupled to said phase estimator, said convolutional decoder being configured to receive and decode said phase estimate values to produce a decoded data stream that corresponds to said second portion of said information bits; a convolutional encoder coupled to said convolutional decoder to generate a re-encoded bit stream; and a demodulation look-up table coupled to said phase estimator and to said convolutional encoder, said table being configured to generate hard data estimates which correspond to said first portion of said information bits in response to said phase estimate values and said re-encoded bit stream.

Claim 35

A programmable decoding apparatus as claimed in claim 31 wherein: said pragmatic modulation scheme implements a phase point constellation that includes a plurality of primary sub-constellations identified by said encoded bit stream and a plurality of secondary sub-constellations identified by said first portion of said information bits; and said look-up table is configured to generate data estimate decisions based upon primary sub-constellations identified by said re-encoded bit stream.

Claim 36

A programmable decoding apparatus as claimed in claim 31 wherein said pragmatic modulation scheme is rotationally invariant, and said decoding apparatus additionally comprises: a first differential decoder coupled to said look-up table to generate data estimates of said first portion of said information bits; and a second differential decoder coupled to said convolutional decoder to generate data estimates of said second portion of said information bits.

Claim 37

A programmable decoding apparatus as claimed in claim 31 wherein said pragmatic modulation scheme is amplitude phase shift keyed (APSK) modulation, said phase estimate stream conveys quadrature phase and magnitude for each unit interval, and said decoding apparatus additionally comprises: a carrier phase recovery loop having an input coupled to said phase estimator and being configured to adjust said quadrature phase in response to said quadrature magnitude to generate a phase-adjusted signal, said phase-adjusted signal being used for carrier tracking.

Claim 38

A programmable decoding apparatus as claimed in claim 31 wherein said pragmatic modulation scheme employs puncturing in connection with said convolutional encoding, and said decoding apparatus additionally comprises: a depuncture circuit coupled between said phase estimator and said convolutional decoder, said depuncture circuit being configured to periodically generate erasure values so that said erasure values vary in response to said phase estimate values generated by said phase estimator.

Claim 39

A programmable decoding apparatus as claimed in claim 35 wherein: said apparatus additionally comprises a first branch metric processor configured to generate branch metrics for use by said convolutional decoder during unit intervals where puncturing has not occurred, said first branch metric processor being responsive to said phase estimate values; and said depuncture circuit comprises a second branch metric processor configured to generate branch metrics for use by said convolutional decoder during unit intervals where puncturing has occurred, said second branch metric processor being responsive to said phase estimate values.

Claim 40

A programmable decoding apparatus as claimed in claim 36 wherein: said first branch metric processor supplies two likelihood values to said convolutional decoder for each phase estimate value processed therein; and said second branch metric processor is configured to provide a first likelihood value and a duplicate of said first likelihood value to said convolutional decoder for each phase estimate value processed therethrough.

Claim 41

A programmable decoding apparatus as claimed in claim 37 wherein said second branch metric processor is configured to provide a second likelihood value and a duplicate of said second likelihood value to said convolutional decoder for each phase estimate value processed therethrough.

Claim 42

A programmable decoding apparatus as claimed in claim 36 wherein: each phase estimate value conveys first and second convolutionally encoded symbols; for one of said phase estimate values, said second branch metric processor generates a value describing the likelihood that said first symbol exhibits a predetermined polarity; and said second branch metric processor is configured so that said first symbol likelihood value is compensated to null out influence of said second symbol.

Claim 43

A programmable decoding apparatus as claimed in claim 35 wherein said depuncture circuit comprises a plurality of memory elements configured to be downloaded with different data sets, said different data sets being configured to control depuncturing for different code rates.