Dual layer signal processing in a layered modulation digital signal system

• US 7,173,981 B1
• Filed: 02/05/2002
• Issued: 02/06/2007
• Est. Priority Date: 04/27/2001
• Status: Expired due to Fees

• Current Assignee: Hughes Electronics Corporation (Rtx Corporation)
• Original Assignee: The DIRECTV Group, Inc. (AT&T, Inc.)
• Inventors: Santoru, Joseph, Chen, Ernest C., Hilmes, Philip R., Furuya, Tiffany S.
• Primary Examiner(s): Ghebretinsae; Temesghen
• Assistant Examiner(s): TORRES, JUAN A
• Application Number:
  US10/068,047
• Time in Patent Office: 1,827 Days
• Field of Search: 375/316, 375/320, 375/343, 375/261, 375/235, 375/298, 375/349, 375/308, 375/377, 375/279, 375/281, 342/252, 332/103, 329/304, 329/308, 370/206, 455/17
• US Class Current: 375/322
• CPC Class Codes: H04H 20/30 by a single channel
• CPC Class Codes: H04H 40/90 specially adapted for satellite broadcast receiving
• CPC Class Codes: H04L 27/3488 Multiresolution systems
• CPC Class Codes: H04N 21/234327 by decomposing into layers, e.g. base layer and one or more enhancement layers
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 21/4382 Demodulation or channel decoding, e.g. QPSK demodulation analog front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 5/455 Demodulation-circuits

Abstract

Systems and methods for receiving layered modulation for digital signals are presented. An exemplary apparatus comprises a tuner for receiving a layered signal and producing a layered in-phase signal and a layered quadrature signal therefrom, an analog-to-digital converter for digitizing the layered in-phase signal and the layered quadrature signal and a processor for decoding the layered in-phase signal and the layered quadrature signal to produce one or more discrete layer signals.

Claims

1. An apparatus for receiving a non-coherently layered modulation signal comprising a lower layer signal non-coherently layered with an upper layer signal, comprising:

a tuner for receiving the non-coherently layered modulation signal and producing a non-coherently layered in-phase signal and a non-coherently layered quadrature signal therefrom;

an analog-to-digital converter for digitizing the non-coherently layered in-phase signal and the non-coherently layered quadrature signal; and

a processor for decoding the non-coherently layered in-phase signal and the non-coherently layered quadrature signal to produce the upper layer signal and the lower layer signal.

2. The apparatus of claim 1, wherein the processor comprises a logic circuit.

3. The apparatus of claim 1, further comprising a first decoder for and decoding the upper layer signal to be displayed, and a second decoder for decoding the lower layer signal.

4. The apparatus of claim 1, wherein decoding by the processor performs frequency acquisition on the non-coherently layered quadrature signal.

5. The apparatus of claim 1, wherein decoding by the processor march filters the non-coherently layered in-phase signal and the non-coherently layered quadrature signal.

6. The apparatus of claim 1, wherein the processor produces an ideal upper layer signal including an ideal in-phase upper layer signal and an ideal quadrature upper layer signal from the decoded upper layer signal and subtracts the ideal in-phase upper layer signal and the ideal quadrature upper layer signal from the layered in-phase signal and the layered quadrature signal, respectively, to produce a lower layer in-phase signal and a lower layer quadrature signal of a lower one of the one or more discrete layer signals.

7. The apparatus of claim 6, wherein the processor demodulates and decodes the lower layer in-phase signal and the lower layer quadrature signal to produce the lower layer signals.

8. The apparatus of claim 6, wherein the processor match filters the lower layer in-phase signal and the lower layer quadrature signal.

9. The apparatus of claim 6, wherein the layered in-phase signal and the layered quadrature signal are delayed to synchronize the subtraction.

10. The apparatus of claim 9, wherein delaying the layered in-phase signal and the layered quadrature signal are delayed by correlating to the ideal in-phase upper layer signal and the ideal quadrature upper layer signal.

11. The apparatus of claim 6, wherein producing the ideal upper layer signal comprises signal processing the ideal in-phase upper layer signal and the ideal quadrature upper layer signal.

12. The apparatus of claim 11, wherein signal processing the ideal in-phase upper layer signal and the ideal quadrature upper layer signal comprises finite impulse response matched filtering the ideal in-phase upper layer signal and the ideal quadrature upper layer signal.

13. The apparatus of claim 11, wherein signal processing the ideal in-phase upper layer signal and the ideal quadrature upper layer signal comprises applying a signal map to the ideal in-phase upper layer signal and the ideal quadrature upper layer signal, the signal map accounting for transmission distortions of the layered signal.

14. The apparatus of claim 11, wherein signal processing the ideal in-phase upper layer signal and the ideal quadrature upper layer signal comprises amplitude and phase matching the ideal in-phase upper layer signal and the ideal quadrature upper layer signal with the layered in-phase signal and the layered quadrature signal, respectively.

15. A processor for decoding a non-coherently layered modulation signal comprising a lower layer signal non-coherently layered with an upper layer signal into the upper layer signal and the lower layer signal, comprising:

a first demodulator and first decoder for demodulating and decoding the upper layer signal from the non-coherently layered modulation signal and providing the demodulated and decoded upper layer signal at a first output;

an encoder for generating an ideal upper layer signal from the decoded upper layer signal;

a signal processor for modifying the ideal upper layer signal to characterize transmission and processing effects;

a subtractor for subtracting the modified ideal upper layer signal from the non-coherently layered modulation signal to produce the lower layer signal; and

a second demodulator and second decoder for demodulating and decoding the lower layer signal and providing the decoded lower layer signal at a second output.

16. The processor of claim 15, further comprising a delay function correlated to an output of the signal processor to appropriately delay the non-coherently layered modulation signal to synchronize amplitude and phase matching of the modified ideal upper layer signal and the layered signal.

17. The processor of claim 15, further comprising a delay function correlated to an output of the signal processor to appropriately delay the non-coherently layered modulation signal to synchronize subtraction of the modified ideal upper layer signal and the layered signal.

18. The processor of claim 15, wherein the signal processor performs finite impulse response matched filtering on the ideal upper layer signal.

19. The processor of claim 15, wherein the signal processor performs finite impulse response matched filtering on the delayed layered signal.

20. The processor of claim 15, wherein the signal processor applies a signal map to the ideal upper layer signal.

21. The processor of claim 15, wherein the signal processor amplitude and phase matches the ideal upper layer signal with the layered signal.

22. A method of decoding a non-coherently layered modulation signal comprising a lower layer signal non-coherently layered with an upper layer signal, comprising the steps of:

receiving the non-coherently layered modulation signal and producing a non-coherently layered in-phase signal and a non-coherently layered quadrature signal therefrom;

digitizing the non-coherently layered in-phase signal and the non-coherently layered quadrature signal; and

decoding the digitized non-coherently layered in-phase signal and the non-coherently layered quadrature signal to produce the upper layer signal and the lower layer signal.

23. The method of claim 22, wherein the step of decoding is performed by a logic circuit.

24. The method of claim 22, wherein the step of decoding includes frequency acquisition on the layered quadrature signal.

25. The method of claim 22, further comprising receiving and decoding the upper layer signal and the lower layer signal.

26. The method of claim 22, wherein the step of decoding comprises matched filter the non-coherently layered in-phase signal and the non-coherently layered quadrature signal.

27. The method of claim 22, wherein the step of decoding comprises demodulating and decoding an upper layer signal from the non-coherently layered in-phase signal and the non-coherently layered quadrature signal to produce the upper layer signal.

28. The method of claim 27, wherein the step of decoding comprises producing an ideal upper layer signal including an ideal in-phase upper layer signal and an ideal quadrature upper layer signal from the decoded upper layer signal and subtracting the ideal in-phase upper layer signal and the ideal quadrature upper layer signal from the non-coherently layered in-phase signal and the non-coherently layered quadrature signal, respectively, to produce a lower layer in-phase signal and a lower layer quadrature signal of the lower layer signals.

29. The method of claim 28, wherein the step of decoding comprises demodulating and decoding the lower layer in-phase signal and the lower layer quadrature signal to produce the lower one of the one or more discrete layer signals.

30. The method of claim 28, wherein the step of decoding comprises match filtering the lower layer in-phase signal and the lower layer quadrature signal.

31. The method of claim 28, wherein the step of decoding comprises delaying the layered in-phase signal and the layered quadrature signal to synchronize the subtraction.

32. The method of claim 31, wherein delaying comprises correlating the layered in-phase signal and the layered quadrature signal.

33. The method of claim 28, wherein producing the ideal upper layer signal comprises signal processing the ideal in-phase upper layer signal and the ideal quadrature upper layer signal.

34. The method of claim 33, wherein signal processing the ideal in-phase upper layer signal and the ideal quadrature upper layer signal comprises pulse shaping the ideal in-phase upper layer signal and the ideal quadrature upper layer signal.

35. The method of claim 33, wherein signal processing the ideal in-phase upper layer signal and the ideal quadrature upper layer signal comprises applying a signal map to the ideal in-phase upper layer signal and the ideal quadrature upper layer signal, the signal map accounting for transmission distortions of the layered signal.

36. The method of claim 33, wherein signal processing the ideal in-phase upper layer signal and the ideal quadrature upper layer signal comprises amplitude and phase matching the ideal in-phase upper layer signal and the ideal quadrature upper layer signal with the non-coherently layered in-phase signal and the non-coherently layered quadrature signal, respectively.