Various methods and apparatuses for imulse noise mitigation

• US 20060078044A1
• Filed: 10/11/2005
• Published: 04/13/2006
• Est. Priority Date: 10/11/2004
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Fisher, Kevin D., Schley-May, James T., Wiese, Brian, Norrell, Andrew L., Sedarat, Hossein, Artman, Douglas J.
• Granted Patent: US 8,194,722 B2
• Time in Patent Office: Days
• US Class Current: 375/222
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0046 Determination of how many bits are transmitted on different sub-channels
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/1438 Negotiation of transmission parameters prior to communication modified according to link quality H04L1/0001

Abstract

Methods and apparatuses for reducing effects of impulse noise in a DSL transmitter receiver device are described. According to certain embodiment, the method includes using a periodicity associated with the impulse noise affecting a DSL transmitter receiver device to determine data frames that are affected by the impulse noise, and sending a reduced data rate during those frames. In certain embodiments, no data is sent during those frames. The method further includes using a high margin bits and gain table, instead of a normal bits and gain table.

Claims

1. A digital subscriber line (DSL) modem, having a receiver comprising:

an impulse noise predictor to predict if data frames will be affected by impulse noise based upon a periodicity of impulse noise; and

a demodulator to use a first table to provide data when data frames are predicted to be affected by the impulse noise by the impulse noise predictor and a second table to provide data if the data frames are not predicted as being affected by the impulse noise by the impulse noise predictor.

2. The DSL modem recited in claim 1, wherein the first table is a bits and gain table that has a first noise margin high enough to protect against impulse noise.

3. The DSL modem recited in claim 2, wherein the second table is also a bitts and gain table has a second noise margin lower than the first noise margin.

4. The DSL modem of claim 3, wherein the first bits and gain table has a lower data rate than the second bits and gain table.

5. The DSL modem of claim 1, wherein the impulse noise detector detects the impulse noise periodicity as well as a duration of the impulse noise to predict when a next occurrence of impulse noise will occur.

6. The DSL modem of claim 2, wherein the impulse noise predictor determines a frame number to start using the first noise margin and a number of frames to continue to use the first noise margin.

7. The DSL modem of claim 4, wherein the first bits and gain table has a data rate of zero.

8. A machine readable storage medium to store instructions representing the impulse noise predictor of claim 1.

9. A method for impulse noise mitigation, comprising:

using a periodicity associated with impulse noise to predict a subset of DMT data frames from a set of data transmissions that are affected by the impulse noise; and

sending a first data rate during the subset of frames lower than a second data rate during DMT data frames outside of the subset of frames.

10. The method recited in claim 9, further comprising:

increasing an operating noise margin on the subset of data frames as compared to the DMT data frames outside of the subset of frames.

11. The method recited in claim 10, further comprising:

using a first bits and gain table having a first noise margin high enough to protect against impulse noise to provide data during the subset of frames.

12. The method recited in claim 11, further comprising:

switching to a second bits and gain table having a lower noise margin than the first noise margin when the effects of the impulse noise is predicted to subside.

13. The method recited in claim 9, further comprising:

sending blank data frames during the subset of frames.

14. The method recited in claim 9, further comprising:

using Reed-Solomon coding when a repeatable periodicity cannot be established for with the impulse noise.

15. A DSL system comprising:

a first transmitter-receiver device having a receiver, the receiver having an impulse noise predictor to determine if data frames will be affected by impulse noise using an impulse noise periodicity, wherein the first transmitter-receiver device has a detector to detect control parameters associated with the impulse noise; and

a second transmitter-receiver device having a transmitter to reduce its transmission data rate upon receiving the control parameters from the first transmitter-receiver device.

16. The DSL system recited in claim 15, wherein the second transmitter receiver device reduces the data rate using a bits and gain table to carry data, the bits and gain table having a noise margin set to protect data to be carried against impulse noise.

17. The DSL system recited in claim 16, wherein the first transmitter-receiver device to communicate control parameters and the bits and gain table over an enhanced online reconfiguration (OLR) channel to the second transmitter-receiver device.

18. The DSL system recited in claim 15, wherein the receiver of the first transmitter receiver device comprises an impulse noise detector to detect presence of impulse noise in the DSL system.

19. The DSL system recited in claim 16, wherein the control parameters comprise at least one of a (1) time relative to a beginning of a first frame predicted to be affected by impulse noise, (2) an impulse duration, (3) an impulse frequency, and (4) a future frame number to start using the bits and gain table.

20. The DSL system recited in claim 17, wherein the enhanced OLR channel is used to synchronize the bits and gain table between the first and second transmitter receiver devices.

21. An apparatus, comprising:

means for using a periodicity associated with impulse noise to predict a subset of DMT data frames from a set of data transmissions that are affected by the impulse noise; and

means for sending a first data rate during the subset of frames lower than a second data rate during DMT data frames outside of the subset of frames.