Apparatus and method for processing a Quadrature Amplitude Modulated (QAM) signal
First Claim
Patent Images
1. A receiver for receiving a Quadrature Amplitude Modulation (QAM) modulated bitstream containing phasor points represented in a QAM constellation, said receiver comprising:
- a first decoder for decoding the QAM modulated bitstream with respect to a Quaternary Phase Shift Keying (QPSK) constellation to produce a decoded bitstream; and
a second decoder, coupled to said first decoder, for decoding the QAM modulated bitstream with respect to a QPSK constellation within a hierarchial subset region of the QAM constellation defined by said first decoder.
3 Assignments
0 Petitions
Accused Products
Abstract
Apparatus and method for receiving a QAM signal using a backward compatible hierarchical coding scheme to increase data transmission using finer constellations, while maintaining compatibility with existing Direct Broadcasting Satellite (DBS) systems. The apparatus employs multiple stages of decoders such that the finer constellations of the QAM signal are unraveled at different stages.
209 Citations
19 Claims
-
1. A receiver for receiving a Quadrature Amplitude Modulation (QAM) modulated bitstream containing phasor points represented in a QAM constellation, said receiver comprising:
-
a first decoder for decoding the QAM modulated bitstream with respect to a Quaternary Phase Shift Keying (QPSK) constellation to produce a decoded bitstream; and a second decoder, coupled to said first decoder, for decoding the QAM modulated bitstream with respect to a QPSK constellation within a hierarchial subset region of the QAM constellation defined by said first decoder. - View Dependent Claims (2, 3)
-
-
4. A receiver for receiving a Quadrature Amplitude Modulation (QAM) modulated bitstream containing phasor points represented in a QAM constellation, said receiver comprising:
-
a first decoder for decoding the QAM modulated bitstream with respect to a Quaternary Phase Shift Keying (QPSK) constellation to produce a decoded bitstream; a second decoder, coupled to said first decoder, for decoding the QAM modulated bitstream with respect to a QPSK constellation within a subset region of the QAM constellation defined by said first decoder; a delay, coupled to said second decoder, for applying a delay; and a reencoder, coupled to said first decoder, for generating information relating to said subset region defined by said first decoder. - View Dependent Claims (5)
-
-
6. A receiver for receiving a Quadrature Amplitude Modulation (QAM) modulated bitstream containing phasor points represented in a QAM constellation, said receiver comprising:
-
a first decoder for decoding the QAM modulated bitstream with respect to a Quaternary Phase Shift Keying (QPSK) constellation to produce a decoded bitstream; a second decoder, coupled to said first decoder, for decoding the QAM modulated bitstream with respect to a QPSK constellation within a subset region of the QAM constellation defined by said first decoder; and an outer decoder, coupled said first decoder, for decoding said decoded bitstream from said first decoder. - View Dependent Claims (7, 8)
-
-
9. A method of decoding a Quadrature Amplitude Modulation (QAM) signal having a plurality of QAM phasor points represented by a QAM constellation diagram having "n" hierarchical levels of Quaternary Phase Shift Keying (QPSK) constellation, said method comprising the steps of:
-
a) using a first decoder to decode a first hierarchical level of the QAM signal with respect to a QPSK constellation to produce a decoded signal; and b) using a second decoder to decode a second hierarchical level of the QAM signal with respect to a QPSK constellation, within a subset region of the QAM constellation defined by said first decoder. - View Dependent Claims (11, 12)
-
-
10. A method of decoding a Quadrature Amplitude Modulation (QAM) signal having a plurality of QAM phasor points represented in a QAM constellation diagram having "n" hierarchical levels of Quaternary Phase Shift Keying (QPSK) constellation, said method comprising the steps of:
-
a) using a first decoder to decode a first hierarchical level of the QAM signal with respect to a QPSK constellation to produce a decoded signal; b) using a second decoder to decode a second hierarchical level of the QAM signal with respect to a QPSK constellation, within a subset region of the QAM constellation defined by said first decoder;
whereinadditional decoders are used to decode additional hierarchical levels of the QAM signal.
-
-
13. A method of decoding a Quadrature Amplitude Modulation (QAM) signal having a plurality of QAM phasor points represented by a QAM constellation diagram having "n" hierarchical levels of Quaternary Phase Shift Keying (QPSK) constellation, said method comprising the steps of:
-
a) using a first decoder to decode a first hierarchical level of the QAM signal with respect to a QPSK constellation to produce a decoded signal; and b) using a second decoder to decode a second hierarchical level of the QAM signal with respect to a QPSK constellation, within a subset region of the QAM constellation defined by said first decoder; further comprising the steps of; a1) applying a delay to the QAM signal; and a2) encoding said decoded signal from said first decoder to generate information relating to said subset region defined by said first decoder.
-
-
14. A method of decoding a Quadrature Amplitude Modulation (QAM) signal having a plurality of QAM phasor points represented by a QAM constellation diagram having "n" hierarchical levels of Quaternary Phase Shift Keying (QPSK) constellation, said method comprising the steps of:
-
a) using a first decoder to decode a first hierarchical level of the QAM signal with respect to a QPSK constellation to produce a decoded signal; and b) using a second decoder to decode a second hierarchical level of the QAM signal with respect to a QPSK constellation, within a subset region of the QAM constellation defined by said first decoder; further comprising the step of; c) using a third decoder to decode said decoded signal from said first decoder. - View Dependent Claims (15, 16)
-
-
17. In a satellite signal receiver, a method of decoding a Quadrature Amplitude Modulation (QAM) signal having a plurality of QAM symbol points represented by a QAM constellation diagram having N hierarchical levels of a Quaternary Phase Shift Keyed (QPSK) constellation, said method comprising the steps of:
-
demodulating an input QAM signal received from a satellite transmission channel to produce a demodulated QAM signal; and using a plurality of decoders for successively decoding respective hierarchical levels of said demodulated QAM signal. - View Dependent Claims (18, 19)
-
Specification