Metric calculation design for variable code rate decoding of broadband trellis, TCM, or TTCM
First Claim
1. A metric generator that determines a metric associated with a received symbol according to a rate control sequence, the metric generator comprising:
- a plurality of predetermined in-phase (I) coefficients;
a plurality of predetermined quadrature (Q) coefficients;
a plurality of I summing blocks that selectively sums an I component of the received symbol with each of the predetermined I coefficients thereby generating a plurality of I sums;
a plurality of Q summing blocks that selectively sums a Q component of the received symbol with each of the predetermined Q coefficients thereby generating a plurality of Q sums;
a plurality of I squaring blocks that squares each I sum of the plurality of I sums thereby generating a plurality of squared I sums;
a plurality of Q squaring blocks that squares each Q sum of the plurality of Q sums thereby generating a plurality of squared Q sums;
a square output multiplexor that receives the plurality of squared I sums and the plurality of squared Q sums and outputs a plurality of I outputs and a plurality of Q outputs;
a plurality of I,Q summing blocks that selectively sums the plurality of I outputs and the plurality of Q outputs from the square output multiplexor according to the rate control sequence thereby generating a plurality of I,Q outputs;
a plurality of min* processing blocks that processes the plurality of I,Q outputs according to the rate control sequence thereby generating a plurality of output metrics; and
a metric output multiplexor that selects an output metric from the plurality of output metrics according to the rate control sequence.
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Abstract
Metric calculation design for variable code rate decoding of broadband trellis, TCM (trellis coded modulated), or TTCM (turbo trellis coded modulation). A single design can accommodate a large number of code rates by multiplexing the appropriate paths within the design. By controlling where to scale for any noise of a received symbol within a received signal, this adaptable design may be implemented in a manner that is very efficient in terms of performance, processing requirements (such as multipliers and gates), as well as real estate consumption. In supporting multiple code rates, appropriately selection of the coefficients of the various constellations employed, using the inherent redundancy and symmetry along the I and Q axes, can result in great savings of gates borrowing upon the inherent redundancy contained therein; in addition, no subtraction (but only summing) need be performed when capitalizing on this symmetry.
20 Citations
62 Claims
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1. A metric generator that determines a metric associated with a received symbol according to a rate control sequence, the metric generator comprising:
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a plurality of predetermined in-phase (I) coefficients; a plurality of predetermined quadrature (Q) coefficients; a plurality of I summing blocks that selectively sums an I component of the received symbol with each of the predetermined I coefficients thereby generating a plurality of I sums; a plurality of Q summing blocks that selectively sums a Q component of the received symbol with each of the predetermined Q coefficients thereby generating a plurality of Q sums; a plurality of I squaring blocks that squares each I sum of the plurality of I sums thereby generating a plurality of squared I sums; a plurality of Q squaring blocks that squares each Q sum of the plurality of Q sums thereby generating a plurality of squared Q sums; a square output multiplexor that receives the plurality of squared I sums and the plurality of squared Q sums and outputs a plurality of I outputs and a plurality of Q outputs; a plurality of I,Q summing blocks that selectively sums the plurality of I outputs and the plurality of Q outputs from the square output multiplexor according to the rate control sequence thereby generating a plurality of I,Q outputs; a plurality of min* processing blocks that processes the plurality of I,Q outputs according to the rate control sequence thereby generating a plurality of output metrics; and a metric output multiplexor that selects an output metric from the plurality of output metrics according to the rate control sequence. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A metric generator that determines a metric associated with a received symbol according to a rate control sequence, the metric generator comprising:
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a square output multiplexor that selectively outputs a plurality of in-phase (I) associated outputs and a plurality of quadrature (Q) associated outputs according to the rate control sequence; wherein the rate control sequence comprises a plurality of modulations; wherein each modulation of the plurality of modulations comprises a constellation and a mapping; wherein the plurality of I associated outputs being indicative of I-axis distances separating an I component of the received symbol and a plurality of predetermined I coefficients corresponding to the constellation; and wherein the plurality of Q associated outputs being indicative of Q-axis distances separating a Q component of the received symbol and a plurality of predetermined Q coefficients corresponding to the constellation; and a plurality of min* processing blocks that processes selected I,Q sums according to the rate control sequence to generate a plurality of output metrics, wherein the selected I,Q sums comprising sums of an I associated output from the plurality of I associated outputs and a Q associated output from the plurality of Q associated outputs; and a metric output multiplexor that selects an output metric from the plurality of output metrics according to the rate control sequence. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A metric generator that determines a metric associated with a received symbol according to a rate control sequence, the metric generator comprising:
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a plurality of sigma scaling blocks that scales an in-phase (I) component of the received symbol and a quadrature (Q) component of the received symbol based on a signal to noise ratio of the received symbol; a plurality of predetermined, scaled I coefficients that are scaled based on the signal to noise ratio of the received symbol; and a plurality of predetermined, scaled Q coefficients that are scaled based on the signal to noise ratio of the received symbol; a plurality of I summing blocks that selectively sums the scaled I component of the received symbol with each of the predetermined, scaled I coefficients thereby generating a plurality of I sums; a plurality of Q summing blocks that selectively sums the scaled Q component of the received symbol with each of the predetermined, scaled Q coefficients thereby generating a plurality of Q sums; a plurality of I squaring blocks that squares each I sum of the plurality of I sums thereby generating a plurality of squared I sums; a plurality of Q squaring blocks that squares each Q sum of the plurality of Q sums thereby generating a plurality of squared Q sums; a square output multiplexor that receives the plurality of squared I sums and the plurality of squared Q sums and outputs a plurality of I outputs and a plurality of Q outputs; a plurality of I,Q summing blocks that selectively sums the plurality of I outputs and the plurality of Q outputs from the square output multiplexor according to the rate control sequence thereby generating a plurality of I,Q outputs; a plurality of min* processing blocks that processes the plurality of I,Q outputs thereby generating a plurality of output metrics according to the rate control sequence; and a metric output multiplexor that selects an output metric from the plurality of output metrics according to the rate control sequence. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47)
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48. A metric generator method that calculates a metric associated with a received symbol according to a rate control sequence, the method comprising:
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calculating a plurality of in-phase (I) sums using an I component of a received symbol and a plurality of predetermined I coefficients; calculating a plurality of quadrature (Q) sums using a Q component of the received symbol and a plurality of predetermined Q coefficients; squaring each I sum of the plurality of I sums; squaring each Q sum of the plurality of Q sums; selectively summing an I sum of the plurality of I sums with a Q sum of the plurality of Q sums thereby generating a plurality of I,Q outputs according to the rate control sequence; performing min* processing on the plurality of I,Q outputs to generate a plurality of output metrics according to the rate control sequence; and outputting one metric from the plurality of output metrics according to the rate control sequence. - View Dependent Claims (49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62)
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Specification