DMT SYMBOL REPETITIOIN IN THE PRESENCE OF IMPULSE NOISE

• US 20070217491A1
• Filed: 10/14/2005
• Published: 09/20/2007
• Est. Priority Date: 10/15/2004
• Status: Active Grant

• Current Assignee: TQ Delta LLC (Techquity Capital Management, LLC)
• Original Assignee: Aware Incorporated (Crowley Holdings Preferred LLC)
• Inventors: Tzannes, Marcos
• Granted Patent: US 7,796,705 B2
• Time in Patent Office: Days
• US Class Current: 375/222
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence
• CPC Class Codes: H04B 3/50 Systems for transmission between fixed stations via two-conductor transmission lines H04B3/54 takes precedence
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0011 applied to payload information
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 1/007 Unequal error protection for format H04L1/0078; for codes per se H03M13/35
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 1/20 using signal quality detector
• CPC Class Codes: H04M 11/062 using different frequency bands for speech and other data

Abstract

With the current initialization procedures defined in the VDSL and ADSL standards, even though the xDSL system could operate in Showtime in an impulse noise environment where symbols are being corrupted, the transceivers would not be able to reach Showtime because initialization would fail due to initialization message failure. Through the use of an improved initialization procedure for communication systems, operation in environments with higher levels of impulse noise is possible.

Claims

1. A communication system initialization method comprising determining a number of DMT symbols to be repeated during initialization based on an impulse noise protection value.

2. The method of claim 1, wherein a transmitting modem performs the determining step.

3. The method of claim 1, wherein a receiving modem performs the determining step.

4. The method of claim 1, wherein the number of DMT symbols to be repeated is computed as N=A*INP+B, where A and B are integers and INP is an impulse noise protection value.

5. The method of claim 1, wherein the number of DMT symbols to be repeated is computed as N=INP+1, where INP is an impulse noise protection value.

6. The method of claim 1, further comprising:

modulating at least one message bit onto the repeated DMT symbols; and

transmitting the number of repeated DMT symbols.

7. The method of claim 6, further comprising:

modulating at least one CRC bit onto each repeated DMT symbol.

8. The method of claim 1, further comprising:

receiving the number of repeated DMT symbols; and

demodulating at least one message bit from the repeated DMT symbol.

9. The method of claim 8, further comprising demodulating at least one CRC bit from each repeated DMT symbol.

10. The method of claim 1, wherein the repeated DMT symbols are consecutive, identical DMT symbols.

11. The method of claim 1, wherein the repeated DMT symbols are a sequence of substantially identical DMT symbols.

12. The method of claim 1, wherein the repeated DMT symbols are a sequence of identical DMT symbols.

23. Means for performing the functionality of any of claims 1-22.

24. An information storage media having information stored thereon that performs the functionality of any of claims 1-22.

25. A communication protocol that performs the method of any of claims 1-22.

13. A communication system initialization method comprising:

utilizing an impulse noise protection value to determine a repeat value, the repeat value specifying the number of DMT symbols to be repeated during initialization.

14. A communication system initialization method comprising:

repeating a DMT symbol a number of times during initialization message transmission; and

utilizing a cyclic redundancy checksum to validate the integrity of received initialization messages.

15. A communication system initialization method comprising:

determining how many DMT symbols should be repeated during initialization based on an impulse noise protection value.

16. A communication system initialization method comprising:

modulating at least one message bit onto a number of repeated DMT symbols; and

transmitting the number of repeated DMT symbols.

17. A communication system initialization method comprising:

modulating at least one bit onto a DMT symbol; and

repeating the DMT symbol a number of times in an initialization message.

18. A communication system initialization method comprising:

determining an information to cyclic redundancy checksum ratio; and

modulating at least one or more cyclic redundancy checksums onto a DMT symbol during initialization.

19. A communication system initialization method wherein a cyclic redundancy checksum and repeated DMT symbols are used for initialization messages.

20. A communication system initialization method comprising modulating error detection information onto a DMT symbol during initialization.

21. A communication system initialization method comprising modulating error detection information onto one or more DMT symbols.

22. A communication system initialization method comprising:

modulating error detection information onto a plurality of DMT symbols;

assembling the DMT symbols into a consecutive sequence of identical DMT symbols; and

repeatedly transmitting the consecutive sequence of identical DMT symbols.

26. A communication system comprising:

a DMT symbol repetition module designed to determine a number of DMT symbols to be repeated during initialization based on an impulse noise protection value.

27. The system of claim 26, wherein the DMT symbol repetition module is in a transmitting modem.

28. The system of claim 26, wherein the DMT symbol repetition module is in a receiving modem.

29. The system of claim 26, wherein the number of DMT symbols to be repeated is computed as N=A*INP+B, where A and B are integers and INP is an impulse noise protection value.

30. The system of claim 26, wherein the number of DMT symbols to be repeated is computed as N=INP+1, where INP is an impulse noise protection value.

31. The system of claim 26, further comprising:

a modulation module designed to modulate at least one message bit onto the repeated DMT symbols; and

a transmitter module designed to transmit the number of repeated DMT symbols.

32. The system of claim 31, wherein the modulation module is also designed to modulate at least one CRC bit onto each repeated DMT symbol.

33. The system of claim 26, further comprising:

a receiver module designed to receive the number of repeated DMT symbols; and

a demodulation module designed to demodulate at least one message bit from the repeated DMT symbol.

34. The system of claim 33, wherein the demodulation module is also designed to demodulate at least one CRC bit from each repeated DMT symbol.

35. The system of claim 26, wherein the repeated DMT symbols are consecutive, identical DMT symbols.

36. The system of claim 26, wherein the repeated DMT symbols are a sequence of substantially identical DMT symbols.

37. The system of claim 26, wherein the repeated DMT symbols are a sequence of identical DMT symbols.

38. Means for protecting against impulse noise during initialization comprising:

analyzing an initialization message length; and

one or more of repeating DMT symbols during initialization and modulating error detection information onto a DMT symbol during initialization.

39. An impulse noise initialization error mitigation system comprising:

means for determining an impulse noise mitigation technique; and

means for implementing the determined technique.

40. A communication system comprising means for associating error detection information with one or more DMT symbols transmitted during initialization.

41. A communication system comprising means for associating error detection information with one or more DMT symbols received during initialization.

42. A communication system comprising:

means for analyzing a number of repeated DMT symbols that are received during initialization and determining which one or more of the repeated DMT symbols have errors.

43. The system of claim 42, further comprising means for selecting an error free repeated DMT symbol.