Error free dynamic rate change in DSL with constant delay

• US 20060150059A1
• Filed: 11/16/2005
• Published: 07/06/2006
• Est. Priority Date: 11/16/2004
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Modlin, Cory S.
• Granted Patent: US 7,457,993 B2
• Time in Patent Office: Days
• US Class Current: 714/755
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/22 Traffic shaping
• CPC Class Codes: H04L 47/25 with rate being modified by the source upon detecting a change of network conditions
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes

Abstract

A method for charging the data rate over an interleaved latency path overcomes shortfalls of the ADSL2 seamless rate adaptation (SRA) and dynamic rate repartitioning (DRR). The interleaver depth is allowed to change during either a rate charge or rate repartioning so that the interleaver delay is constant before and after the change. The transmitter pauses its transmission for a time approximately equal to the delay of the interleaver so that there are approximately no errors introduced at the receiver.

Claims

1. A method for data transmission rate change for a digital subscriber line (DSL) transmission, comprising:

changing an interleaver depth on an interleaved data path during the DSL transmission of data.

2. The method of claim 1, wherein an end-to-end delay between a receiver and a transmitter is maintained approximately constant before and after the rate change.

3. The method of claim 2, wherein there are no data errors resulting from the change in interleaver depth

4. The method of claim 1, further comprising:

providing a break in the data stream, wherein the break has a length approximately equal to a delay of the interleaver.

5. The method of claim 1, changing an end-to-end delay before and after the rate change to effect a change in the impulse noise protection.

6. The method of claim 5, wherein there are no data errors resulting from the change in interleaver depth

7. The method of claim 1, wherein the changing the interleaver depth comprises draining the interleaver by continuing to read data out of the interleaver while adding no new data to the interleaver before the change in interleaver depth.

8. The method of claim 7, wherein the draining the interleaver comprises inserting at least (D−

1)*(I−

1) octets in the data transmission to drain the interleaver, wherein D is an initial interleaver depth and I is an initial interleaver length

9. The method of claim 8, wherein the inserting comprises draining the interleaver and ending on a codeword boundary by inserting D−

1 complete codewords.

10. The method of claim 9, further comprising:

changing to an interleaver with a new interleaver depth immediately after the complete codewords are inserted.

11. The method of claim 9, further comprising:

switching to a new number of bits per DMT frame on a next frame boundary after the complete codewords are inserted.

12. The method of claim 1, further comprising:

discarding invalid data at a receiver at the receiver after the change in interleaver depth.

13. The method of claim 12, wherein the discarding comprises discarding the invalid data after waiting exactly (D−

1)*(I−

1) octets until a deinterleaver is primed, wherein D is a new interleaver depth and I is a new interleaver length.

14. A method for a data rate change over a digital subscriber line (DSL), comprising:

changing an interleaver length (l) on an interleaved data path on the DSL line

15. The method of claim 14, wherein the changing comprises maintaining an approximately constant end-to-end delay before and after the rate change.

16. The method of claim 14, wherein the changing comprises increasing or decreasing the impulse noise protection

17. The method of claim 14, further comprising:

providing a break in the data stream, wherein the break has a length approximately equal to a delay of the interleaver.