SYNCHRONIZED SLOTTED POWER LINE COMMUNICATION

• US 20150263785A1
• Filed: 03/14/2014
• Published: 09/17/2015
• Est. Priority Date: 03/14/2014
• Status: Active Grant

• Current Assignee: Semtech Ev, Inc. (Semtech Corporation)
• Original Assignee: Semtech Ev, Inc. (Semtech Corporation)
• Inventors: Farrokhi, Farrokh, Anburaj, Michael
• Granted Patent: US 9,749,012 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 2203/542 using zero crossing information
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines
• CPC Class Codes: H04J 3/0638 Clock or time synchronisation among nodes; Internode synchronisation synchronization for ring networks H04L12/422; data switching networks with synchronous transmission H04L12/43
• CPC Class Codes: H04L 2007/047 using a sine signal or unmodulated carrier

Abstract

A method and a device are disclosed including a PLC node having a synchronizer, a modem with a transceiver, and a computing device coupled with a power line for power line data communications. In various embodiments, a coordinator or Data Concentrator Unit (DCU) coordinates the communication of PLC nodes. The PLC nodes are configured to detect a zero crossing of the power line wave form and transmit or receive data within time slots defined with respect to the detected zero crossing. In other embodiments, the time slots may be synchronized using a frame sync signal, an external signal, or polling. In various embodiments, the time slots may be random access or assigned. In some embodiments, the modem and/or node may be placed in a sleep mode when not communicating to reduce power consumption and be awaken when an allocated time slot is approaching.

Claims

1. A Power Line Communication (PLC) system comprising:

a power line configured to carry AC current; and

a PLC node coupled with the power line and configured to detect a specific point on an AC current waveform including one of a zero-crossing, minimum, and maximum point of the AC current waveform, and further configured to transmit data over the power line upon detection of the zero-crossing point.

2. The PLC system of claim 1, further comprising a Data Concentration Unit (DCU) coupled with the power line.

3. The PLC system of claim 2, wherein the DCU is configured to assign a time slot to generate a frame sync signal coincident with the zero-crossing point.

4. The PLC system of claim 2, wherein the DCU is configured to register a PLC node during a discovery period and assign a time slot to the PLC node for data transmission.

5. The PLC system of claim 2, wherein the PLC node comprises a frame sync signal detector module and a modem device.

6. The PLC system of claim 2, wherein the PLC frame sync signal marks the beginning of a set of time frames comprising a plurality of time slots, wherein each time slot spans a full cycle of the AC current or a half cycle of the AC current.

7. The PLC system of claim 1, wherein the PLC node comprises a zero-crossing detector module and a modem device.

8. The PLC system of claim 1, wherein the PLC transmits data using one of OFDMA (Orthogonal Frequency Division Multiple Access), TDMA (Time Division Multiple Access), and CDMA (Code Division Multiple Access) communication protocols.

9. A Power Line Communication (PLC) system comprising:

a power line configured to carry AC current;

a Data Concentration Unit (DCU) configured to generate a data frame synchronization signals; and

a PLC node coupled with the power line and configured to detect the data frame synchronization signal and further configured to transmit data over the power line upon detection of the frame synchronization signal.

10. The PLC system of claim 9, wherein the PLC node comprises a frame synchronization detector module, a modem, and a computing device.

11. The PLC system of claim 9, wherein the DCU is further configured to register a plurality of PLC nodes during a discovery period and assign a different time slot to each of the plurality of the PLC nodes.

12. The PLC system of claim 9, wherein the data frame synchronization signal marks the beginning of a plurality of time slots.

13. The PLC system of claim 9, wherein the DCU is configured to send a polling message to each of a plurality of PLC nodes to synchronize transmission by each of the plurality of PLC nodes

14. The PLC system of claim 9, wherein each PLC is configured to transmit data during one of a time slot assigned to the PLC and a random time slot.

15. A method of communicating data over a Power Line Communication (PLC) system, the method comprising:

detecting a zero-crossing of an AC current transmitted over a power line;

indicating the event of zero-crossing to at least one Power Line Communication (PLC) node; and

transmitting data over the power line after receiving the indication of the event of zero-crossing.

16. The method of claim 15, further comprising detecting a frame sync signal and indicating the detection of the frame sync signal to the at least one PLC node.

17. The method of claim 15, further comprising transmitting an ID or a signature by the at least one PLC node to a Data Concentrator Unit (DCU) during a discovery period.

18. The method of claim 15, further comprising assigning a time slot by a Data Concentrator Unit (DCU) to the at least one PLC node to be used for data transmission by the at least one PLC node.

19. The method of claim 15, wherein the PLC node is configured to use an assigned time slot or a random time slot to transmit data.

20. The method of claim 15, further comprising polling the at least one PLC node to synchronize data transmissions by the at least one PLC node.