Communication decoder employing single trellis to support multiple code rates and/or multiple modulations
First Claim
1. An apparatus, comprising:
- a rate control sequencer that is operable to provide a rate control sequence having a plurality of rate controls arranged in a period, wherein;
each rate control of a plurality of rate controls has a modulation selected from a plurality of modulations;
each modulation of the plurality of modulations has a constellation selected from a plurality of constellations, a mapping selected from a plurality of mappings, and a bandwidth efficiency selected from a plurality of bandwidth efficiencies;
each encoded symbol of a plurality of encoded symbols is encoded according to a rate control of the plurality of rate controls;
for each encoded symbol of the plurality of encoded symbols, a metric generator is operable to calculate a plurality of metrics according to a rate control that corresponds to that encoded symbol;
for each encoded symbol of the plurality of encoded symbols, the plurality of metrics are mapped to a plurality of trellis metrics based on a trellis according to the rate control that corresponds to that encoded symbol;
a top soft-in soft-out functional block (SISO) that, based on the plurality of trellis metrics, is operable to calculate a first plurality of extrinsic values for each encoded symbol of the plurality of encoded symbols according to the respective rate control;
an interleaver, communicatively coupled to the top SISO, that is operable to interleave the first plurality of extrinsic values to generate a first “
a priori probability”
(app) information;
a bottom SISO that, based on the plurality of trellis metrics, is operable to calculate a second plurality of extrinsic values for each encoded symbol of the plurality of encoded symbols according to the respective rate control;
a de-interleaver, communicatively coupled to the bottom SISO, that is operable to de-interleave the second plurality of extrinsic values to generate a second “
a priori probability”
(app) information, wherein;
the first “
a priori probability”
(app) information is fed back to the bottom SISO;
the second “
a priori probability”
(app) information is fed back to the top SISO;
the top SISO and the bottom SISO operate cooperatively to perform at least one iteration of iterative decoding to generate a plurality of soft symbol decisions, each soft symbol decision of the plurality of soft symbol decisions corresponds to an encoded symbol of the plurality of encoded symbols; and
an output processor, communicatively coupled to the bottom SISO, that is operable to generate a hard symbol decision for each soft symbol decision of the plurality of soft symbol decisions thereby making a best estimate for each encoded symbol of the plurality of encoded symbols.
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Abstract
Communication decoder employing single trellis to support multiple code rates and/or multiple modulations. A single trellis is employed by the decoder to decode a plurality of encoded symbols. Each of the plurality of encoded symbols is governed by a rate control. A rate control sequence, having a period, is used to decode the plurality of encoded symbols that may be arranged within a frame. Various parameters of the plurality of encoded symbols may vary on a symbol by symbol basis; these parameters may include modulation, constellation, mapping, and/or bandwidth efficiency. For example, various symbols may be encoded differently, yet they may all be decoded using the same trellis. The functionality of this decoder may be implemented within a variety of different decoder embodiments including a trellis code modulation (TCM) decoder, a turbo trellis code modulation (TTCM) decoder, and/or a parallel concatenated turbo code modulation (PC-TCM) decoder.
29 Citations
55 Claims
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1. An apparatus, comprising:
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a rate control sequencer that is operable to provide a rate control sequence having a plurality of rate controls arranged in a period, wherein; each rate control of a plurality of rate controls has a modulation selected from a plurality of modulations; each modulation of the plurality of modulations has a constellation selected from a plurality of constellations, a mapping selected from a plurality of mappings, and a bandwidth efficiency selected from a plurality of bandwidth efficiencies; each encoded symbol of a plurality of encoded symbols is encoded according to a rate control of the plurality of rate controls; for each encoded symbol of the plurality of encoded symbols, a metric generator is operable to calculate a plurality of metrics according to a rate control that corresponds to that encoded symbol; for each encoded symbol of the plurality of encoded symbols, the plurality of metrics are mapped to a plurality of trellis metrics based on a trellis according to the rate control that corresponds to that encoded symbol; a top soft-in soft-out functional block (SISO) that, based on the plurality of trellis metrics, is operable to calculate a first plurality of extrinsic values for each encoded symbol of the plurality of encoded symbols according to the respective rate control; an interleaver, communicatively coupled to the top SISO, that is operable to interleave the first plurality of extrinsic values to generate a first “
a priori probability”
(app) information;a bottom SISO that, based on the plurality of trellis metrics, is operable to calculate a second plurality of extrinsic values for each encoded symbol of the plurality of encoded symbols according to the respective rate control; a de-interleaver, communicatively coupled to the bottom SISO, that is operable to de-interleave the second plurality of extrinsic values to generate a second “
a priori probability”
(app) information, wherein;the first “
a priori probability”
(app) information is fed back to the bottom SISO;the second “
a priori probability”
(app) information is fed back to the top SISO;the top SISO and the bottom SISO operate cooperatively to perform at least one iteration of iterative decoding to generate a plurality of soft symbol decisions, each soft symbol decision of the plurality of soft symbol decisions corresponds to an encoded symbol of the plurality of encoded symbols; and an output processor, communicatively coupled to the bottom SISO, that is operable to generate a hard symbol decision for each soft symbol decision of the plurality of soft symbol decisions thereby making a best estimate for each encoded symbol of the plurality of encoded symbols. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. An apparatus, comprising:
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an input that is operable to receive a plurality of encoded symbols that is encoded according to a rate control sequence having a plurality of rate controls arranged in a period, wherein each encoded symbol of the plurality of encoded symbols is encoded according to a rate control of the plurality of rate controls; a top soft-in soft-out functional block (SISO) that, based on a plurality of trellis metrics, is operable to calculate a first plurality of extrinsic values for each encoded symbol of the plurality of encoded symbols according to the respective rate control; an interleaver that is operable to interleave the first plurality of extrinsic values to generate a first “
a priori probability”
(app) information;a bottom SISO that, based on the plurality of trellis metrics, is operable to calculate a second plurality of extrinsic values for each encoded symbol of the plurality of encoded symbols according to the respective rate control; a de-interleaver that is operable to de-interleave the second plurality of extrinsic values to generate a second “
a priori probability”
(app) information, wherein;the first “
a priori probability”
(app) information is fed back to the bottom SISO;the second “
a priori probability”
(app) information is fed back to the top SISO;the top SISO and the bottom SISO operate cooperatively to perform at least one iteration of iterative decoding to generate a plurality of soft symbol decisions, each soft symbol decision of the plurality of soft symbol decisions corresponds to an encoded symbol of the plurality of encoded symbols; and an output processor, communicatively coupled to the bottom SISO, that is operable to generate a hard symbol decision for each soft symbol decision of the plurality of soft symbol decisions thereby making a best estimate for each encoded symbol of the plurality of encoded symbols. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55)
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Specification