VARIABLE LINE CYCLE ADAPTATION FOR POWERLINE COMMUNICATIONS

• US 20140269874A1
• Filed: 03/13/2013
• Published: 09/18/2014
• Est. Priority Date: 03/13/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Rajkotia, Purva R., Yonge, Lawrence W. III, Afkhami, Hassan K.
• Granted Patent: US 8,891,605 B2
• Time in Patent Office: Days
• US Class Current: 375/227
• CPC Class Codes: H04B 3/04 Control of transmission; Equalising
• CPC Class Codes: H04B 3/10 by pilot signal
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines
• CPC Class Codes: H04B 3/544 Setting up communications; Call and signalling arrangements

Abstract

Line cycle adaptation periods having variable duration are disclosed. A powerline cycle may be segmented into a plurality of line cycle adaptation periods having variable duration based upon signal-to-noise (SNR) characteristics measured at various times throughout the powerline cycle. The line cycle adaptation periods may include at least two periods with unequal durations. Each line cycle adaptation period may be associated with one or more tone maps defining physical layer transmission properties to be used by a second device for transmissions occurring during the line cycle adaptation period.

Claims

1. A method comprising:

determining, at a first device, signal-to-noise (SNR) characteristics of received signals at various times during a powerline cycle;

determining, at the first device, line cycle adaptation periods within the powerline cycle based upon the SNR characteristics, the line cycle adaptation periods including at least two periods with unequal durations; and

coordinating the line cycle adaptation periods with a second device such that subsequent transmissions from the second device are in accordance with line cycle adaptation properties specific to each line cycle adaptation period.

2. The method of claim 1, wherein said coordinating the line cycle adaptation periods with the second device comprises transmitting a line cycle adaptation period definition message to the second device.

3. The method of claim 1, wherein said coordinating the line cycle adaptation periods with the second device comprises associating a tone map with each line cycle adaptation period, the tone map defining transmission properties to be used during each line cycle adaptation period.

4. The method of claim 1, wherein said coordinating the line cycle adaptation periods with the second device comprises transmitting an extended tone map message that defines transmission properties and timing information associated with at least one line cycle adaptation period.

5. The method of claim 4, wherein said timing information includes a start time relative to a predefined transition of the powerline cycle and a duration.

6. The method of claim 1 wherein said determining the line cycle adaptation periods comprises:

initially setting a set of line cycle adaptation periods to have equal durations; and

merging two consecutive line cycle adaptation periods to create a longer line cycle adaptation period if SNR characteristics for the two consecutive line cycle adaptation periods are within a threshold amount of each other.

7. The method of claim 1, further comprising:

splitting a particular line cycle adaptation period into two or more smaller line cycle adaptation periods if SNR characteristics for portions of the particular line cycle adaptation period are not within a threshold amount of each other.

8. The method of claim 1, wherein said determining the line cycle adaptation periods comprises:

determining SNR characteristics periodically during the powerline cycle, including a first SNR measurement at a first time instance of the powerline cycle and a subsequent second SNR measurement at a second time instance of the powerline cycle; and

setting a line cycle adaptation period boundary between the first time instance and the second time instance if the difference between the first SNR measurement and the second SNR measurement exceeds a threshold amount, the line cycle adaptation period boundary associated with an end of a first line cycle adaptation period and a beginning of a subsequent second line cycle adaptation period.

9. The method of claim 1, wherein said determining SNR characteristics comprises measuring SNR characteristics on a per-OFDM-symbol basis.

10. The method of claim 9, further comprising:

averaging SNR measurements for each corresponding symbol slot over a plurality of powerline cycles; and

determining a baseline pattern of SNR values for each symbol slot of the powerline cycle, wherein the line cycle adaptation periods are based upon the baseline pattern of SNR values.

11. The method of claim 1, wherein a quantity of line cycle adaptation periods determined is based at least in part upon a number of nodes in a powerline communications cell.

12. An apparatus comprising:

an SNR measurement unit configured to determine signal-to-noise (SNR) characteristics of received signals at various times during a powerline cycle; and

a line cycle adaptation module, the line cycle adaptation module configured to;

determine line cycle adaptation periods within the powerline cycle based upon the SNR characteristics, the line cycle adaptation periods including at least two periods with unequal durations; and

coordinate the line cycle adaptation periods with a second device such that subsequent transmissions from the second device are in accordance with line cycle adaptation properties specific to each line cycle adaptation period.

13. The apparatus of claim 12, wherein the line cycle adaptation module is configured to coordinate the line cycle adaptation periods with the second device by transmitting a line cycle adaptation period definition message to the second device.

14. The apparatus of claim 12, wherein the line cycle adaptation module is configured to coordinate the line cycle adaptation periods with the second device by associating a tone map with each line cycle adaptation period, the tone map defining transmission properties to be used during each line cycle adaptation period.

15. The apparatus of claim 12, wherein the line cycle adaptation module is configured to coordinate the line cycle adaptation periods with the second device by transmitting an extended tone map message that defines transmission properties and timing information associated with at least one line cycle adaptation period.

16. The apparatus of claim 15, wherein said timing information includes a start time relative to a predefined transition of the powerline cycle and a duration.

17. The apparatus of claim 12, wherein the line cycle adaptation module is configured to:

initially set a set of line cycle adaptation periods to have equal durations; and

merge two consecutive line cycle adaptation periods to create a longer line cycle adaptation period if SNR characteristics for the two consecutive line cycle adaptation periods are within a threshold amount of each other.

18. The apparatus of claim 17, wherein the line cycle adaptation module is configured to:

split a particular line cycle adaptation period into two or more smaller line cycle adaptation periods if SNR characteristics for portions of the particular line cycle adaptation period are not within a threshold amount of each other.

19. The apparatus of claim 12,

wherein the SNR measurement unit is configured to determine SNR characteristics periodically during the powerline cycle, including a first SNR measurement at a first time instance of the powerline cycle and a subsequent second SNR measurement at a second time instance of the powerline cycle;

and

wherein the line cycle adaptation module is configured to set a line cycle adaptation period boundary between the first time instance and the second time instance if the difference between the first SNR measurement and the second SNR measurement exceeds a threshold amount, the line cycle adaptation period boundary associated with an end of a first line cycle adaptation period and a beginning of a subsequent second line cycle adaptation period.

20. The apparatus of claim 12, wherein the SNR measurement unit is configured to measure SNR characteristics on a per-OFDM-symbol basis.

21. A non-transitory computer readable medium storing computer program code, the computer program code comprising instructions which when executed by a processor of a device cause the device to:

determine signal-to-noise (SNR) characteristics of received signals at various times during a powerline cycle;

determine line cycle adaptation periods within the powerline cycle based upon the SNR characteristics, the line cycle adaptation periods including at least two periods with unequal durations; and

coordinate the line cycle adaptation periods with a second device such that subsequent transmissions from the second device are in accordance with line cycle adaptation properties specific to each line cycle adaptation period.

22. The non-transitory computer readable medium of claim 21, wherein the instructions which when executed by the processor of the device cause the device to coordinate the line cycle adaptation periods with the second device comprises instructions which when executed by the processor of the device cause the device to:

transmit a line cycle adaptation period definition message to the second device;

associate a tone map with each line cycle adaptation period, the tone map defining transmission properties to be used during each line cycle adaptation period;

or

transmit an extended tone map message that defines transmission properties and timing information associated with at least one line cycle adaptation period.

23. The non-transitory computer readable medium of claim 21, further comprising instructions which when executed by the processor of the device cause the device to:

initially set a set of line cycle adaptation periods to have equal durations; and

merge two consecutive line cycle adaptation periods to create a longer line cycle adaptation period if SNR characteristics for the two consecutive line cycle adaptation periods are within a threshold amount of each other, or

split a particular line cycle adaptation period into two or more smaller line cycle adaptation periods if SNR characteristics for portions of the particular line cycle adaptation period are not within a threshold amount of each other.