System and methods for synchronizing edge devices on channels without carrier sense

• US 9,848,446 B2
• Filed: 06/16/2016
• Issued: 12/19/2017
• Est. Priority Date: 08/03/2011
• Status: Active Grant

• Current Assignee: Dominion Enterprises (Landmark Media Enterprises LLC), TRC Companies Incorporated
• Original Assignee: Dominion Enterprises (Landmark Media Enterprises LLC), Astrolink International Llc (Qurate Retail Group (f/k/a Liberty Interactive Corporation))
• Inventors: Martin, Marcia R., Abendschein, Andrew Louis, Bernheim, Henrick F.
• Primary Examiner(s): PARK, JUNG H
• Application Number:
  US15/184,642
• Publication Number:
  US 20160302238A1
• Time in Patent Office: 551 Days
• CPC Class Codes: H04L 41/5022 by giving priorities, e.g. assigning classes of service
• CPC Class Codes: H04L 47/6245 Modifications to standard FIFO or LIFO
• CPC Class Codes: H04L 7/04 Speed or phase control by synchronisation signals H04L7/0075 takes precedence
• CPC Class Codes: H04W 28/065 using assembly or disassembly of packets
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 74/0891 for synchronized access

Abstract

A system and method are disclosed for synchronizing edge devices on a network, wherein the network has limited bandwidth and does not support a practical carrier sense mechanism. The edge devices transmit, using a slotted protocol, to a server located at a central data aggregation point. The server also controls a Central Transmitter, which sends messages to the edge devices to assign transmission slots and provide timing information to the edge devices to ensure that transmissions sent by devices sharing the same communication channel do not collide.

Claims

1. A queue server comprising:

a memory configured to maintain a message queue; and

a processor device communicatively coupled to the memory and configured to;

receive, from a master framing agent, a master frame announcement (MFA) that identifies a future time of a corresponding master frame, the corresponding master frame comprising a plurality of time slots, each time slot associated with a particular intelligent communicating device (ICD) of a plurality of ICDs that are coupled to an electrical distribution grid on a low voltage side of a transformer;

insert the MFA into the message queue;

determine that a transmitter coupled to the electrical distribution grid on a high voltage side of the transformer is ready to transmit;

retrieve the MFA from the message queue;

insert a current time into the MFA; and

provide the MFA to the transmitter for transmission onto the electrical distribution grid.

2. The queue server of claim 1 wherein the processor device is further configured to insert the MFA at a front of the message queue in front of a plurality of other messages in the message queue.

3. The queue server of claim 1 wherein the processor device is further configured to iteratively provide a plurality of MFAs to the transmitter for transmission onto the electrical distribution grid at arbitrary times.

4. A method comprising:

receiving, by a queue server comprising a processor device from a master framing agent, a master frame announcement (MFA) that identifies a future time of a corresponding master frame, the corresponding master frame comprising a plurality of time slots, each time slot associated with a particular intelligent communicating device (ICD) of a plurality of ICDs that are coupled to an electrical distribution grid on a low voltage side of a transformer;

inserting the MFA into a message queue;

determining that a transmitter coupled to the electrical distribution grid on a high voltage side of the transformer is ready to transmit;

retrieving the MFA from the message queue;

inserting a current time into the MFA; and

providing the MFA to the transmitter for transmission onto the electrical distribution grid.

5. The method of claim 4 further comprising inserting the MFA at a front of the message queue in front of a plurality of other messages in the message queue.

6. The method of claim 4 further comprising iteratively providing a plurality of MFAs to the transmitter for transmission onto the electrical distribution grid at arbitrary times.

7. An intelligent communicating device (ICD) comprising:

a communications interface configured to be coupled to an electrical distribution grid on a low voltage side of a transformer;

a clock; and

a processor device communicatively coupled to the communications interface and the clock, and configured to;

receive a respective master frame announcement (MFA) of a plurality of MFAs transmitted at arbitrary times through the transformer by a transmitter coupled to the electrical distribution grid on a high voltage side of the transformer, each MFA identifying a time of transmission of the respective MFA and a future time of a corresponding master frame, the corresponding master frame comprising a plurality of time slots, each time slot associated with a particular ICD of a plurality of ICDs;

based on the time of transmission of the respective MFA and the future time of the corresponding master frame, synchronize the clock;

await the future time of the corresponding master frame; and

transmit data on the electrical distribution grid to the high voltage side of the transformer in a time slot of the corresponding master frame that is associated with the ICD.

8. The intelligent communicating device of claim 7 wherein the processor device is further configured to access a policy that identifies the time slot of the corresponding master frame that is associated with the ICD.

9. A method comprising:

receiving, by an intelligent communicating device (ICD) coupled to an electrical distribution grid on a low voltage side of a transformer, a respective master frame announcement (MFA) of a plurality of MFAs transmitted at arbitrary times through the transformer by a transmitter coupled to the electrical distribution grid on a high voltage side of the transformer, each MFA identifying a time of transmission of the respective MFA and a future time of a corresponding master frame, the corresponding master frame comprising a plurality of time slots, each time slot associated with a particular ICD of a plurality of ICDs;

based on the time of transmission of the respective MFA and the future time of the corresponding master frame, synchronizing a clock of the ICD;

awaiting the future time of the corresponding master frame; and

transmitting data on the electrical distribution grid to the high voltage side of the transformer in a time slot of the corresponding master frame that is associated with the ICD.

10. The method of claim 9 further comprising accessing a policy that identifies the time slot of the corresponding master frame that is associated with the ICD.

11. A queue server comprising:

a communications interface configured to communicate via a data communications network; and

a processor device configured to;

maintain a queue of messages, at least one of the messages comprising a master frame announcement (MFA) that identifies a future time of a corresponding master frame, the corresponding master frame comprising a plurality of time slots associated with communications via an electrical distribution grid, each time slot associated with a particular ICD of a plurality of ICDs coupled to the electrical distribution grid located on a low voltage side of a transformer;

receive a request from a first ICD of the plurality of ICDs via the data communications network; and

in response to the request, send, via the data communications network, a subset of messages in the queue of messages, the subset of messages including the MFA, to the first ICD.

12. The queue server of claim 11 wherein each message in the queue of messages includes a unique sequence number, and wherein the processor device is further configured to:

maintain, for each respective ICD of the plurality of ICDs, a corresponding unique sequence number that identifies a largest sequence number of any message previously sent to the respective ICD; and

wherein to send the subset of messages to the first ICD the processor device is further configured to;

access the corresponding unique sequence number that identifies a largest sequence number of any message previously sent to the first ICD;

send to the first ICD each message in the queue of messages having a unique sequence number that is greater than the largest sequence number of any message previously sent to the first ICD;

determine the largest sequence number of any message sent to the first ICD; and

store the largest sequence number as the corresponding unique sequence number that identifies the largest sequence number of any message previously sent to the first ICD.

13. A method comprising:

maintaining, by a queue server comprising a processor device, a queue of messages, at least one of the messages comprising a master frame announcement (MFA) that identifies a future time of a corresponding master frame, the corresponding master frame comprising a plurality of time slots associated with communications via an electrical distribution grid, each time slot associated with a particular ICD of a plurality of ICDs coupled to the electrical distribution grid located on a low voltage side of a transformer;

receiving a request from a first ICD of the plurality of ICDs via a data communications network, the data communications network being different from the electrical distribution grid; and

in response to the request, sending, via the data communications network, a subset of messages in the queue of messages, the subset of messages including the MFA, to the first ICD.

14. The method of claim 13 wherein each message in the queue of messages includes a unique sequence number, and further comprising:

maintaining, for each respective ICD of the plurality of ICDs, a corresponding unique sequence number that identifies a largest sequence number of any message previously sent to the respective ICD; and

wherein sending the subset of messages to the first ICD further comprises;

accessing the corresponding unique sequence number that identifies the largest sequence number of any message previously sent to the first ICD;

sending to the first ICD each message in the queue of messages having a unique sequence number that is greater than the largest sequence number of any message previously sent to the first ICD;

determining the largest sequence number of any message sent to the first ICD; and

storing the largest sequence number as the corresponding unique sequence number that identifies the largest sequence number of any message previously sent to the first ICD.