Channel Selection in Power Line Communications

• US 20120201155A1
• Filed: 02/01/2012
• Published: 08/09/2012
• Est. Priority Date: 02/08/2011
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Du, Shu, Dabak, Anand G., Lu, Xiaolin, Kim, Il Han
• Granted Patent: US 8,995,461 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04B 2203/5408 using protocols
• CPC Class Codes: H04B 2203/5466 using three phases conductors
• CPC Class Codes: H04B 2203/5495 having measurements and testing channel
• 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
• CPC Class Codes: H04L 12/10 Current supply arrangements
• CPC Class Codes: H04L 43/0823 Errors, e.g. transmission errors
• CPC Class Codes: H04L 7/00 Arrangements for synchronising receiver with transmitter synchronisation of generators of electric oscillations or pulses H03L7/00

Abstract

Systems and methods for channel selection in power line communications (PLC) are described. In some embodiments, a method may include defining a plurality of frames, each frame having a plurality of time slots. The method may also include assembling a pair of beacon and bandscan packets within each of time slot of each frame. The method may further include sequentially transmitting each of the frames over a corresponding one of a plurality of different frequency bands. In some implementations, each bandscan packet may include a slot index indicating a position of its time slot within its respective frame and/or a band index indicating one of the plurality of different frequency bands. In response to having transmitted the plurality of frames, the method may include receiving one or more packets indicating a selection of one or more of the plurality of different frequency bands to be used in subsequent communications.

Claims

1. A method comprising:

performing, by a first power line communication (PLC) device,

defining a plurality of frames, each of the plurality of frames having a plurality of time slots;

assembling a pair of beacon and bandscan packets within each of the plurality of time slots in each of the plurality of frames; and

sequentially transmitting each of the plurality of frames in a corresponding one of a plurality of different frequency bands to a second PLC device over a power line.

2. The method of claim 1, wherein the first PLC device includes a PLC modem.

3. The method of claim 2, wherein the beacon packets are configured to inform the second PLC device that the first PLC device is active.

4. The method of claim 2, wherein each bandscan packet includes a slot index indicating a position of its time slot within its respective frame.

5. The method of claim 4, wherein each bandscan packet includes a band index indicating one of the plurality of different frequency bands.

6. The method of claim 5, wherein each bandscan packet includes information indicating a frequency band distinct from any of the plurality of different frequency bands to be used by the second PLC device to communicate with the first PLC device in a direction from the second PLC device to the first PLC device.

7. The method of claim 6, wherein the information includes at least one of:

signal-to-noise ratio (SNR) or bit error rate (BER) information.

8. The method of claim 2, further comprising:

performing, by the first PLC device,

in response to having transmitted the plurality of frames, receiving one or more packets from the second PLC device indicating a selection of one or more of the plurality of different frequency bands to be used in a communication between the first PLC device and the second PLC device in a direction from the first PLC device to the second PLC device.

9. The method of claim 2, further comprising:

performing, by the first PLC device,

in response to having transmitted the plurality of frames, receiving one or more packets from the second PLC device indicating a signal-to-noise ratio (SNR) or bit error rate (BER) measurement made by the second PLC device in each of the plurality of different frequency bands; and

selecting one or more of the plurality of different frequency bands to be used in a communication between the first PLC device and the second PLC device in a direction from the first PLC device to the second PLC device based, at least in part, upon the SNR or BER measurements.

10. A power line communication (PLC) device comprising:

a processor; and

a memory coupled to the processor, the memory configured to store program instructions executable by the processor to cause the PLC device to;

sequentially scan one or more time slots in each of a plurality of frequency bands;

detect a packet transmitted by a second PLC device to the PLC device over one of the plurality of frequency bands; and

synchronize additional packets received from the second PLC device across the plurality of frequency bands based, at least in part, upon the detected packet, wherein the additional packets are organized in a plurality of frames, each of the plurality of frames having been transmitted by the second PLC device to the PLC device over a respective one of the plurality of frequency bands, each frame having a plurality of time slots, and each time slot having a pair of beacon and bandscan packets.

11. The PLC device of claim 10, wherein the processor includes a digital signal processor (DSP), an application specific integrated circuit (ASIC), a system-on-chip (SoC) circuit, a field-programmable gate array (FPGA), a microprocessor, or a microcontroller.

12. The PLC device of claim 10, wherein the beacon packets are configured to inform the PLC device that the second PLC device is active.

13. The PLC device of claim 12, wherein each bandscan packet includes a slot index indicating a position of its time slot within its respective frame and a band index indicating a corresponding one of the plurality of frequency bands.

14. The PLC device of claim 10, the program instructions further executable by the processor to cause the PLC device to:

calculate a channel quality metric for each of the plurality of frequency bands based, at least in part, upon respective ones of the plurality of frames.

15. The PLC device of claim 14, wherein the channel quality metric includes at least one of a signal-to-noise ratio (SNR) or bit error rate (BER) calculation or estimation.

16. The PLC device of claim 14, the program instructions further executable by the processor to cause the PLC device to:

transmit one or more packets to the second PLC device, each of the one or more packets corresponding to one of the plurality of time slots, and each of one or more packets including an indication of the channel quality metric.

17. The PLC device of claim 14, the program instructions further executable by the processor to cause the PLC device to:

determine when to transmit the one or more packets to the second PLC device based upon at least one of;

a round-robin or a carrier sense multiple access (CSMA) technique.

18. A tangible electronic storage medium having program instructions stored thereon that, upon execution by a processor within a first power line communication (PLC) modem, cause the first PLC modem to:

in a first mode of operation,

define a plurality of frames, each of the plurality of frames having a plurality of time slots;

assemble a pair of beacon and bandscan packets within each of the plurality of time slots in each of the plurality of frames; and

sequentially transmit each of the plurality of frames over a corresponding one of a first plurality of frequency bands to a second PLC modem over a power line; and

in a second mode of operation,

monitor one or more time slots in each of a second plurality of frequency bands over the power line, the second plurality of frequency bands different from the first plurality of frequency bands;

detect a packet transmitted by the second PLC modem over one of the second plurality of frequency bands;

synchronize receipt of additional packets transmitted by the second PLC modem across the second plurality of frequency bands based, at least in part, upon the detected packet;

calculate a channel quality value for each of the second plurality of frequency bands based, at least in part, upon the additional packets; and

select one or more of the second plurality of frequency bands for subsequent communications with the second PLC modem in a direction from the second PLC modem to the first PLC modem based, at least in part, upon the channel quality values.

19. The tangible electronic storage medium of claim 18, wherein the program instructions, upon execution by the processor, further cause the first PLC modem to:

in the first mode of operation,

receive a communication from the second PLC modem indicating one or more of the first plurality of frequency bands to be used in subsequent communications with the second PLC modem in a direction from the first PLC modem to the second PLC modem.

20. The tangible electronic storage medium of claim 18, wherein the program instructions, upon execution by the processor, further cause the first PLC modem to:

in the second mode of operation,

communicate the selected one or more of the second plurality of frequency bands to the second PLC modem over each of the second plurality of frequency bands, the selected one or more of the second plurality of frequency bands to be used in subsequent communications with the PLC modem in a direction from the second PLC modem to the first PLC modem.