Method and system for communicating data in xDSL using data retransmission

• US 8,320,248 B2
• Filed: 09/11/2007
• Issued: 11/27/2012
• Est. Priority Date: 09/13/2006
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Christiaens, Benoit, Peeters, Miguel, Cassiers, Raphael
• Primary Examiner(s): Smith, Marcus R
• Assistant Examiner(s): EBRAHIM, ANEZ C
• Application Number:
  US11/853,532
• Publication Number:
  US 20080062872A1
• Time in Patent Office: 1,904 Days
• Field of Search: 370/535, 370/231, 370/241, 370/242, 370/253, 379/29.1, 379/1.01, 379/22, 379/29.03
• US Class Current: 370/231
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 1/1835 Buffer management
• CPC Class Codes: H04L 1/1877 for semi-reliable protocols, e.g. for less sensitive applications like streaming video buffer level management for video bitstream control arrangements H04N21/44004

Abstract

A method and system for communicating data in an xDSL data retransmission mode is disclosed. A data transmission unit (DTU) is defined. The DTU is sent in an xDSL data stream. A retransmit container is further defined a as a time slot that corresponds to a sent DTU. A copy of the sent DTUs and an index of corresponding retransmit containers is maintained. The DTUs are transmitted the in the xDSL data stream. A determination is made on whether a transmitted DTU was corrupted during transmission. Each corrupted DTU is identified by its corresponding retransmit container. An uncorrupted copy of the DTU is then retransmitted as identified by the corresponding retransmit container.

Claims

1. A method for communicating data between a first device and a second device, comprising:

defining a data transmission unit (DTU) to be sent in an xDSL data stream;

defining a retransmit container as a time slot that corresponds to the DTU;

maintaining a copy of the DTU and the retransmit container at the first device, wherein the retransmit container is maintained at the second device independently of the first device;

transmitting the DTU in the xDSL data stream to the second device;

determining that the DTU was corrupted during transmission;

identifying the DTU based on the retransmit container; and

retransmitting the DTU.

2. The method of claim 1, further comprising identifying the DTU by a sequence identification (SID).

3. The method of claim 2, further comprising defining the DTU as including an overhead byte that supports the SID, the overhead byte being an 8-bit wrap-around counter that increments each time a new DTU is defined.

4. The method of claim 1, further comprising maintaining the DTU for a period of time sufficient to determine whether any of the DTU was corrupted during transmission.

5. The method of claim 1, further comprising defining the DTU as a group of n consecutive code words wherein n=1/S code words and n is an integer.

6. The method of claim 1, further comprising defining the DTU as one of a group of D Reed Solomon code words, a block of asynchronous transfer mode (ATM) cells, or packet transfer mode (PTM) code words.

7. The method of claim 1, further comprising defining the DTU as the set of L bits mapped on a discrete multi-tone (DMT) symbol.

8. The method of claim 1, wherein the determining step further comprises:

receiving a retransmission request indicating that the DTU was corrupted and requesting retransmission of the DTU, wherein the DTU is identified in the retransmission request the retransmit container.

9. The method of claim 8 further comprising:

receiving the retransmission request in a first direction over a retransmit control channel; and

retransmitting the DTU instead of a new DTU.

10. The method of claim 1, wherein the determining step further comprises:

determining that an acknowledgement was not received for the DTU; and

generating a retransmission request identifying the DTU by the retransmit container.

11. The method of claim 1, wherein the maintaining step comprises:

temporarily storing the DTU in a first in first out (FIFO) retransmission buffer, wherein a depth of the FIFO retransmission buffer is determined based on a roundtrip delay between a transmitter that transmits the DTUs and a receiver that receives the DTUs.

12. The method of claim 11, wherein the determining step comprises:

receiving a retransmission request including a value identifying the retransmit container;

wherein the identifying step comprises;

identifying the DTU in the FIFO retransmission buffer based on the value.

13. The method of claim 1, wherein retransmitting the DTU comprises:

retransmitting the DTU using a physical layer of the first device.

14. The method of claim 1, wherein the method occurs in a physical layer of the first device.

15. The method of claim 1, wherein retransmitting the DTU comprises:

retransmitting the DTU such that a maximum round-trip delay allotted for a physical layer of the first device is maintained.

16. A method for communicating data, comprising:

receiving, at a first device, xDSL data transmission units (DTUs) from a second device within respective retransmit containers, wherein a retransmit container is defined as a time slot that corresponds to a respective DTU;

maintaining an index of the retransmit containers at the first device independent of the second device;

determining that a received DTU was corrupted;

transmitting a retransmission request requesting transmission of another copy of the received DTU, wherein the retransmission request includes a value identifying a retransmit container corresponding to the received DTU;

receiving from the second device the other copy of the received DTU; and

substituting the corrupted DTU with the other copy of the DTU.

17. The method of claim 16, further comprising receiving DTUs defined by a sequence identification (SID), therein the other copy of the DTU is identified in the data stream by its corresponding SID.

18. The method of claim 17, further comprising receiving the DTU as further defined by an overhead byte that supports the SID, the overhead byte being an 8-bit wrap-around counter that increments each time a new DTU is defined.

19. The method of claim 16, further comprising receiving DTUs defined as a group of n consecutive code words wherein n=1/S code words and n is an integer.

20. The method of claim 16, further comprising receiving DTUs defined as one of a group of D Reed Solomon code words, a block of asynchronous transfer mode (ATM) cells, or packet transfer mode (PTM) code words.

21. The method of claim 16, further comprising defining the DTU as the set of L bits mapped on a discrete multi-tone (DMT) symbol.

22. The method of claim 16, wherein the received DTU is a first received DTU, further comprising:

determining that a second received DTU was not corrupted; and

transmitting an acknowledgement for the second received DTU over a retransmit control channel, wherein the second received DTU is identified by its corresponding retransmit control container.

23. The method of claim 16, further comprising:

storing the received DTU in a buffer; and

replacing the received DTU in the buffer with the other DTU.

24. A system for communicating data between a first device and a second device, comprising:

means for defining a data transmission unit (DTU) to be sent in an xDSL data stream;

means for defining a retransmit container as a time slot that corresponds to the DTU;

means for maintaining a copy of the DTU and the retransmit container at the first device, wherein the retransmit container is maintained at the second device independent of the first device;

means for transmitting the DTU in the xDSL data stream to the second device;

means for determining that the DTU was corrupted during transmission;

means for identifying the DTU based on the retransmit container; and

means for retransmitting the DTU.

25. The system of claim 24, further comprising means for identifying the DTU by a sequence identification (SID).

26. The system of claim 24, further comprising means for maintaining the DTU for a period of time sufficient to determine whether any of the DTU was corrupted during transmission.

27. The system of claim 24, wherein the determining means further comprises:

means for receiving a retransmission request indicating that the DTU was corrupted and requesting retransmission of DTU, wherein the DTU is identified in the retransmission request the retransmit container.

28. The system of claim 24, further comprising:

means for receiving the retransmission request in a first direction over a retransmit control channel; and

means for retransmitting DTU instead of a new DTU.

29. The system of claim 24, further comprising:

means for temporarily storing the DTU in a first in first out (FIFO) retransmission buffer, wherein a depth of the FIFO retransmission buffer is determined based on a roundtrip delay between a transmitter that transmits the DTUs and a receiver that receives the DTUs.

30. The system of claim 29, further comprising:

means for receiving a retransmission request including a value identifying the retransmit container; and

wherein the identifying means comprises;

means for identifying the DTU in the FIFO retransmission buffer based on the value.

31. A system for communicating data, comprising:

means for receiving, at a first device, xDSL data transmission units (DTUs) from a second device within respective retransmit containers, wherein a retransmit container is defined as a time slot that corresponds to a respective DTUs;

means for maintaining an index of the retransmit containers at the first device independent of the second device;

means for determining that a received DTU was corrupted;

means for transmitting a retransmission request requesting transmission of another copy of the received DTU, wherein the retransmission request includes a value identifying a retransmit container corresponding to the received DTU;

means for receiving from the second device transmitter the other copy of the received DTU; and

means for substituting the corrupted DTU with the other copy of the DTU.

32. The system of claim 31, further comprising means for receiving DTUs defined by a sequence identification (SID), wherein the other copy of the DTU is identified in the data stream by its corresponding SID.

33. The system of claim 31, further comprising:

means for transmitting an acknowledgement for an uncorrupted DTU over a retransmit control channel, wherein the uncorrupted DTU is identified by its corresponding retransmit control container.

34. The system of claim 31, further comprising:

means for storing the received DTU in a buffer; and

means for replacing the received DTU in the buffer with the other DTU.