PHASE NOISE AND FREQUENCY ERROR RESILIENT DEMODULATION SCHEME FOR MOCA

• US 20110080517A1
• Filed: 10/01/2009
• Published: 04/07/2011
• Est. Priority Date: 10/01/2009
• Status: Abandoned Application

• Current Assignee: The DIRECTV Group, Inc. (AT&T, Inc.)
• Original Assignee: The DIRECTV Group, Inc. (AT&T, Inc.)
• Inventors: Zhou, Guangcai
• Application Number:
  US12/572,111
• Publication Number:
  US 20110080517A1
• Time in Patent Office: Days
• US Class Current: 348/433.1
• CPC Class Codes: H04L 2027/0067 Phase error detectors
• CPC Class Codes: H04L 2027/0095 in a preamble or similar structure
• CPC Class Codes: H04L 27/0014 Carrier regulation of chaotic carriers H04L27/001; for multicarrier receivers H04L27/2657
• CPC Class Codes: H04L 27/22 Demodulator circuits; Receiver circuits
• CPC Class Codes: H04L 27/2657 Carrier synchronisation
• CPC Class Codes: H04L 27/2662 Symbol synchronisation
• CPC Class Codes: H04L 27/2679 Decision-aided
• CPC Class Codes: H04L 27/38 Demodulator circuits; Receiver circuits

Abstract

Systems and methods for demodulating signals are disclosed. A system in accordance with the present invention comprises a frequency estimator, a tuner, coupled to the frequency estimator, for tuning to a frequency based on an estimate from the frequency estimator, a phase offset estimator for determining an average phase offset, and a demodulator, coupled to the tuner and the phase offset estimator, for demodulating the plurality of symbols, wherein the demodulator corrects a phase offset for a given symbol in the plurality of the symbols based on the average phase offset of symbols prior to the given symbol.

Claims

1. A system for demodulating a signal comprising a plurality of symbols, comprising:

a frequency estimator;

a tuner, coupled to the frequency estimator, for tuning to a frequency based on an estimate from the frequency estimator;

a phase offset estimator for determining an average phase offset; and

a demodulator, coupled to the tuner and the phase offset estimator, for demodulating the plurality of symbols, wherein the demodulator corrects a phase offset for a given symbol in the plurality of the symbols based on the average phase offset of symbols prior to the given symbol.

2. The system of claim 1, wherein the system is a Multimedia over Coax Alliance (MoCA) system.

3. The system of claim 2, wherein the signal comprises a multi-tone Quadrature Amplitude Modulation (QAM) signal.

4. The system of claim 2, wherein the system further comprises a satellite broadcast system, wherein the satellite broadcast system transmits the signal.

5. The system of claim 4, wherein the signal is a video signal.

6. The system of claim 5, wherein the signal is modulated from BPSK to 1024QAM for individual tones.

7. A method for increasing a data throughput rate of a multimedia system, comprising:

estimating a frequency offset of the channel based on a header of a data frame;

estimating a channel in the multimedia system being used to transmit data; and

correcting a phase offset of each symbol of the data by averaging a phase error of prior symbols in the data frame, wherein the phase error is determined by averaging the absolute value of a difference between an expected phase of each prior symbol in the data frame and a received phase of each prior symbol in the data frame.

8. The method of claim 7, wherein the multimedia system is a Multimedia over Coax Alliance (MoCA) system.

9. The method of claim 8, wherein the signal is a Quadrature Amplitude Modulation (QAM) signal.

10. The method of claim 8, wherein the multimedia system further comprises a satellite broadcast system, wherein the satellite broadcast system transmits the data.

11. The method of claim 10, wherein the signal is a video signal.

12. The method of claim 11, wherein the signal is a Quadrature Amplitude Modulation (QAM) signal for multi-tones.