US 6,005,897 A · Data communication system and method therefor

Abstract

A digital communication system (20) communicates using a polar amplitude phase shift keyed (P-APSK) phase point constellation (70, 70'). Pragmatic encoding and puncturing is accommodated. The pragmatic encoding uses the P-APSK constellation (70, 70') to simultaneously communicate both encoded and uncoded information bits. The P-APSK constellation (70, 70') has an even number of phase point rings (74, 76) and equal numbers of phase points (72) in pairs of the rings (74, 76). Encoded bits specify secondary modulation and uncoded bits specify primary modulation. The constellation (70, 70') is configured so that secondary modulation sub-constellations (78) include four phase points (72) arranged so that two of the four phase points (72) exhibit two phase angles at one magnitude and the other two of the four phase points exhibit phase angles that are at another magnitude. The difference between the phase angles at different magnitudes within a secondary sub-constellation (78) is constant.

Claims40

Dependent claims

An apparatus for decoding a punctured, convolutionally encoded data stream, said apparatus comprising:

a phase estimator configured to generate phase estimate values;
a depuncture circuit coupled to said phase estimator, said depuncture circuit being configured to periodically generate erasure values so that said erasure values vary in response to said phase estimate values;
and
a convolutional decoder coupled to said depuncture circuit and configured to be responsive to said erasure values.

1 more element

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.

2 more elements

Dependencies are inferred from the claim text.

Data communication system and method therefor

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Data communication system and method therefor

Life of this patent

Abstract

Claims40