Variable code rate and signal constellation turbo trellis coded modulation codec
First Claim
Patent Images
1. An apparatus, comprising:
- an input that is operable to receive a signal from a communication channel, wherein;
the signal includes a first symbol, that includes a first number of bits, that has been symbol mapped to a first modulation; and
the signal includes a second symbol, that includes a second number of bits, that has been symbol mapped to a second modulation; and
one decoder that is operable to;
make a first best estimate of the first number of bits within the first symbol; and
make a second best estimate of the second number of bits within the second symbol; and
a rate control sequencer that is operable to provide a rate control sequence, that includes a first rate control and a second rate control, to the one decoder; and
wherein;
the first symbol has been encoded using a first code rate;
the second symbol has been encoded using a second code rate;
the first rate control indicates the first code rate and the first modulation to the one decoder; and
the second rate control indicates the second code rate and the second modulation to the one decoder.
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Abstract
Variable code rate and signal constellation turbo trellis coded modulation (TTCM) codec. The decoding can be performed on signals whose various symbols have been mapped to multiple modulations (constellations and mappings) according to a rate control sequence. The rate control sequence may include a number of rate controls arranged in a period that is repeated during encoding to generate the signal that is subsequently decoded. Either one or both of an encoder that generates the signal and a decoder that decodes the signal may adaptively select a new rate control sequence based on operating conditions of the communication system, such as a change in signal to noise ratio (SNR).
9 Citations
20 Claims
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1. An apparatus, comprising:
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an input that is operable to receive a signal from a communication channel, wherein; the signal includes a first symbol, that includes a first number of bits, that has been symbol mapped to a first modulation; and the signal includes a second symbol, that includes a second number of bits, that has been symbol mapped to a second modulation; and one decoder that is operable to; make a first best estimate of the first number of bits within the first symbol; and make a second best estimate of the second number of bits within the second symbol; and a rate control sequencer that is operable to provide a rate control sequence, that includes a first rate control and a second rate control, to the one decoder; and
wherein;the first symbol has been encoded using a first code rate; the second symbol has been encoded using a second code rate; the first rate control indicates the first code rate and the first modulation to the one decoder; and the second rate control indicates the second code rate and the second modulation to the one decoder. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An apparatus, comprising:
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an input that is operable to receive a signal from a communication channel, wherein; the signal includes a first symbol, that includes a first number of bits, that has been symbol mapped to a first modulation; and the signal includes a second symbol, that includes a second number of bits, that has been symbol mapped to a second modulation; and one decoder that includes a metric generator, a soft-in soft-out functional block (SISO), and an output processor; a rate control sequencer that is operable to provide a rate control sequence, that includes a first rate control and a second rate control, to the one decoder; and
wherein;the first symbol has been encoded using a first code rate; the second symbol has been encoded using a second code rate; the first rate control indicates the first code rate and the first modulation to the one decoder; the second rate control indicates the second code rate and the second modulation to the one decoder; the metric generator is operable to; for the first symbol, calculate a first plurality of metrics that is indexed by a first symbol mapping of constellation points within the first modulation; and for the second symbol, calculate a second plurality of metrics that is indexed by a second symbol mapping of constellation points within the second modulation; the SISO is operable to; for the first symbol, calculate a first soft symbol decision using the first plurality of metrics; and for the second symbol, calculate a second soft symbol decision using the second plurality of metrics; and the output processor is operable to; make a first best estimate of the first number of bits within the first symbol using the first soft symbol decision; and make a second best estimate of the second number of bits within the second symbol using the second soft symbol decision. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A method, comprising:
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receiving a signal from a communication channel, wherein the signal includes a first symbol, that includes a first number of bits, that has been symbol mapped to a first modulation and a second symbol, that includes a second number of bits, that has been symbol mapped to a second modulation; based on a first rate control that indicates the first modulation and a first code rate of the first symbol, decoding the signal using one decoder thereby making a first best estimate of the first number of bits within the first symbol; and based on a second rate control that indicates the second modulation and a second code rate of the second symbol, decoding the signal using the one decoder thereby making a second best estimate of the second number of bits within the second symbol. - View Dependent Claims (18, 19, 20)
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Specification