Time beacons

• US 10,070,403 B2
• Filed: 03/09/2016
• Issued: 09/04/2018
• Est. Priority Date: 03/09/2016
• Status: Active Grant

• Current Assignee: Mueller International LLC (Mueller Water Products Incorporated)
• Original Assignee: Mueller International LLC (Mueller Water Products Incorporated)
• Inventors: Grady, Robert Henry, Splitz, David Edwin, Magley, Dale McLeod
• Primary Examiner(s): Hamza, Faruk
• Assistant Examiner(s): HAQUE, ABUSAYEED M
• Application Number:
  US15/065,423
• Publication Number:
  US 20170265153A1
• Time in Patent Office: 909 Days
• CPC Class Codes: H04L 25/20 Repeater circuits; Relay circuits
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 56/001 Synchronization between nodes

Abstract

Technologies are described herein for time-synchronizing multiple remote network nodes concurrently with time beacons. A hub device in the network, at a preconfigured start time, begins to periodically broadcast time beacons containing current time values retrieved from an accurate time source over a beacon period, while other nodes of the network, at the same preconfigured start time, start listening for time beacons. When a node receives a time beacon broadcast by the hub device, the node sets a real-time clock of the node to the current time value in the received time beacon.

Claims

1. A method for time-synchronizing multiple nodes of a network concurrently comprising steps of:

at a preconfigured start time, broadcasting, by a hub device, a first time beacon containing a current time value retrieved from an accurate time source;

periodically repeating, by the hub device, the broadcasting over a beacon period;

at the preconfigured start time, listening, by a first node of the network, for time beacons;

receiving, at the first node, a received time beacon broadcast by the hub device;

setting, by the first node, a real-time clock of the node to the current time value in the received time beacon;

upon setting the real-time clock of the node to the current time value, waiting, by the first node, a random time in a second delay period; and

after waiting the random time, periodically broadcasting, by the first node, time beacons containing a current time value retrieved from the real-time clock over a remainder of the beacon period.

2. The method of claim 1, further comprising:

determining, by the hub device, a random time in a first delay period; and

waiting, by the hub device, the random time before broadcasting the first time beacon.

3. The method of claim 1, further comprising determining, by the hub device, a plurality of beacon channels over which to broadcast time beacons, wherein the hub device periodically broadcasts time beacons on alternating beacon channels over the beacon period and wherein listening by the first node comprises repeatedly listening for a listening period on alternating beacon channels.

4. The method of claim 1, further comprising:

at the preconfigured start time, listening, by a second node of the network, for time beacons;

receiving, at the second node, a received time beacon broadcast by the first node; and

setting, by the second node, a real-time clock of the second node to the current time value in the received time beacon.

5. The method of claim 1, wherein the first node comprises a repeater in the network.

6. The method of claim 1, wherein the accurate time source comprises a GPS receiver.

7. The method of claim 1, wherein each time beacon comprises an indication of a relative accuracy of the current time value contained therein.

8. The method of claim 1, wherein the network is utilized to connect hub devices and node devices in an Advanced Metering Infrastructure (“

AMI”

) system.

9. The method of claim 8, wherein the first node is connected to a leak detection device in the AMI system.

10. The method of claim 9, wherein the preconfigured start time comprises a short time before the leak detection device is configured to perform acoustic data recording.

11. A system comprising:

a collection hub in an advanced metering infrastructure (“

AMI”

) network connected to an accurate time source and configured with a start time, a beacon period, and a node ID, the collection hub further configured to

determine one or more beacon channels on which to broadcast time beacons based on the node ID,

at the start time, determine a random time within a first delay period to start broadcasting the time beacons, and

after waiting the random time, repeatedly broadcast time beacons on the one or more beacon channels over the beacon period, each time beacon containing a current time value retrieved from the accurate time source; and

a child node in the AMI network configured with the start time and the node ID of the collection hub, the child node further configured to

determine the one or more beacon channels to which to listen based on the node ID of the collection hub,

at the start time, listen for time beacons on the one or more beacon channels, and

upon receiving a time beacon broadcast by the collection hub, set a real-time clock of the child node to the current time value in the received time beacon.

12. The system of claim 11, wherein the one or more beacon channels comprise a pair of hailing channels, wherein repeatedly broadcasting time beacons by the collection hub comprises periodically broadcasting time beacons on alternating hailing channels, and wherein listening for time beacons on the one or more beacon channels by the child node comprises repeatedly listening on alternating hailing channels for a listening period until a time beacon is detected.

13. The system of claim 11, further comprising a repeater in the AMI network configured with the start time and the node ID of the collection hub, the repeater further configured to:

determine the one or more beacon channels to which to listen based on the node ID of the collection hub;

at the start time, listen for time beacons on the one or more beacon channels;

upon receiving a time beacon broadcast by the collection hub, set a real-time clock of the repeater to the current time value in the received time beacon;

determine a random time within a second delay period to start broadcasting time beacons; and

after waiting the random time, repeatedly broadcast time beacons on the one or more beacon channels for a remainder of the beacon period, each time beacon containing a current time value retrieved from the real-time clock of the repeater.

14. The system of claim 11, wherein the accurate time source comprises a GPS receiver.

15. The system of claim 11, wherein each time beacon comprises an indication of a relative accuracy of the current time value contained therein.

16. The system of claim 11, wherein the child node is connected to a leak detection device in the AMI network, and wherein the start time comprises a short time before the leak detection device is configured to perform acoustic data recording.

17. A non-transitory computer-readable storage medium having processor-executable instructions stored thereon that, when executed by a processor in a node of an advanced metering infrastructure (“

AMI”

) system configured as a collection hub, cause the processor to;

determine one or more beacon channels on which to broadcast time beacons based on a node ID of the collection hub;

at a preconfigured start time, determine a random time within a first delay period to start broadcasting the time beacons; and

after waiting the random time, repeatedly broadcast time beacons on the one or more beacon channels over a beacon period, each time beacon containing a current time value retrieved from an accurate time source connected to the collection hub.

18. The non-transitory computer-readable storage medium of claim 17, having further having processor-executable instructions stored thereon that, when executed by a processor in a node of the AMI system configured as a child node, cause the processor to:

determine the one or more beacon channels to which to listen based on the node ID of the collection hub;

at the preconfigured start time, listen for time beacons on the one or more beacon channels; and

upon receiving a time beacon broadcast by the collection hub, set a real-time clock of the child node to the current time value in the received time beacon.

19. The non-transitory computer-readable storage medium of claim 17, having further having processor-executable instructions stored thereon that, when executed by a processor in a node of the AMI system configured as a repeater, cause the processor to:

determine the one or more beacon channels to which to listen based on the node ID of the collection hub;

at the preconfigured start time, listen for time beacons on the one or more beacon channels;

upon receiving a time beacon broadcast by the collection hub, set a real-time clock of the repeater to the current time value in the received time beacon;

determine a random time within a second delay period to start broadcasting time beacons; and

after waiting the random time, repeatedly broadcast time beacons on the one or more beacon channels for a remainder of the beacon period, each time beacon containing a current time value retrieved from the real-time clock of the repeater.