OPTIMIZING PRECODER SETTINGS USING AVERAGE SINR REPORTS FOR GROUPS OF TONES

• US 20090060013A1
• Filed: 08/25/2008
• Published: 03/05/2009
• Est. Priority Date: 08/31/2007
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Inventors: Verlinden, Jan S., Ashikhmin, Alexei E., Whiting, Philip Alfred, Nuzman, Carl Jeremy, Van Bruyssel, Danny, Zivkovic, Miroslav, Maes, Jochen, De Lind Van Wijngaarden, Adriaan J., Kramer, Gerhard Guenter Theodor, Posthuma, Carl Robert
• Granted Patent: US 8,830,812 B2
• Time in Patent Office: Days
• US Class Current: 375/222
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04B 3/32 Reducing cross-talk, e.g. by compensating
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems
• CPC Class Codes: H04L 2025/03414 Multicarrier
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 5/0023 Time-frequency-space

Abstract

Techniques are disclosed for compensating for crosstalk using adaptation of data signals transmitted over respective channels of a communication network. In one example, a method comprises the following steps. Data is transmitted to a communication network device via a communication line during a sequence of periods. For each period of the sequence of periods, a separate value of a measure of crosstalk that was measured at the communication network device is received, each value being an average of measurements at the device of measures of crosstalk for a plurality of communication network signal subcarriers. For each individual signal subcarrier of the plurality, a matrix is updated based on the received values, the matrix being configured to precode data transmissions to the communication network device over the individual signal subcarrier. The communication network may be a DSL system, the signal subcarriers may be DSL tones, and the measure of crosstalk may be a SINR value.

Claims

1. A method, comprising:

transmitting data to a communication network device via a communication line during a sequence of periods;

for each period of the sequence of periods, receiving a separate value of a measure of crosstalk that was measured at the communication network device, each value being an average of measurements at the device of measures of crosstalk for a plurality of communication network signal subcarriers; and

for each individual signal subcarrier of the plurality, updating a matrix based on the received values, the matrix being configured to precode data transmissions to the communication network device over the individual signal subcarrier.

2. The method of claim 1, wherein the updated matrix for one of the signal subcarriers of the plurality being different than the updated matrix for another one of the signal subcarriers of the plurality.

3. The method of claim 1, wherein the updated matrix for one of the signal subcarriers of the plurality being the same as the updated matrix for at least another one of the signal subcarriers of the plurality.

4. The method of claim 1, wherein the plurality of communication network signal subcarriers comprises a plurality of communication network signal subcarriers at nearby frequencies.

5. The method of claim 1, further comprising the step of selecting one or more matrix elements to be updated in a manner configured to increase the value of the measure of crosstalk that is averaged over a plurality of signal subcarriers.

6. The method of claim 5, wherein the step of updating of the matrix for a selected one of the signal subcarriers is based on values of the averaged measures of crosstalk that are measured over a set of the periods wherein the matrix for preceding data transmissions over the selected one of the signal subcarriers is varied and wherein the matrices for preceding data transmissions over the remainder of signal subcarriers of the plurality are kept fixed.

7. The method of claim 5, wherein the updating includes setting one of the matrices for preceding data transmissions over the selected one of the signal subcarriers such that the averaged measure of crosstalk is increased and comprises setting elements of the matrices for precoding data transmissions over other tones of the plurality to interpolate between corresponding elements of the matrix of the selected one of the tones and an updated matrix for precoding data transmissions over a selected signal subcarrier of a second plurality of signal subcarriers.

8. The method of claim 1, further comprising:

transmitting data to one or more second communication network devices via one or more second communication lines during the sequence of periods, the one or more second communication lines being configured to produce interference on the communication line used to transmit data to the first device; and

wherein the transmitting data to the first device comprises transmitting a noise power to the first communication line over the signal subcarriers of the plurality such that a ratio of the noise powers transmitted to first and second ones of the signal subcarriers is about equal to a ratio of the data powers transmitted to one of the second devices over the first and second signal subcarriers.

9. The method of claim 1, wherein the communication network is a digital subscriber line (DSL) system.

10. The method of claim 1, wherein the signal subcarrier is a digital subscriber line (DSL) tone.

11. The method of claim 1, wherein the measure of crosstalk is a signal-to-interference-plus-noise ratio (SINR) value.

12. A method, comprising:

receiving a first crosstalk measure that is averaged over a group of at least two subcarriers;

perturbing a precoder matrix for one or more subcarriers in the group;

receiving at least a second crosstalk measure averaged over the group of at least two subcarriers; and

updating the precoder matrix for one or more subcarriers in the group based on the received crosstalk measures.

13. The method of claim 12, wherein the perturbation step further comprises perturbing a precoder matrix for one subcarrier, while holding precoder matrices for other subcarriers constant.

14. The method of claim 12, wherein the updating step further comprises updating the precoder matrix for one subcarrier only.

15. The method of claim 12, wherein the updating step further comprises updating precoder matrices for all subcarriers using interpolation.

16. The method of claim 12, wherein the perturbation step and the updating step further comprise using a common precoder matrix for all subcarriers in the group.

17. The method of claim 12, wherein the perturbation step and the updating step further comprise using a common power level for all subcarriers in the group.

18. The method of claim 12, wherein the perturbation step and the updating step further comprise adding artificial noise to each subcarrier in a group proportional to the signal power transmitted on a disturber line on each subcarrier.

19. The method of claim 12, wherein, during the perturbation and update steps, precoder matrices for subcarriers in a group are defined by control variables.

20. The method of claim 19, wherein the number of control variables is smaller than the number of coefficients in the precoder matrices.

21. The method of claim 19, wherein the control variables are precoder matrix coefficients for a subset of subcarriers in the group, and precoder matrix coefficients for the remaining subcarriers are determined by interpolation.

22. The method of claim 19, wherein the control variables are updated based on one or more of the received crosstalk measures.