Wireless mesh network controller synchronization

• US 8,345,660 B2
• Filed: 05/06/2010
• Issued: 01/01/2013
• Est. Priority Date: 05/06/2010
• Status: Active Grant

• Current Assignee: Digi International Inc.
• Original Assignee: Digi International Inc.
• Inventors: Filoso, John P., George, Jay Douglas
• Primary Examiner(s): Yao, Kwang B
• Assistant Examiner(s): NGO, NGUYEN HOANG
• Application Number:
  US12/774,932
• Publication Number:
  US 20110274020A1
• Time in Patent Office: 971 Days
• Field of Search: 370/236, 370/311, 370/324, 370/350, 370/503
• US Class Current: 370/350
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 56/002 Mutual synchronization
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A set sleep period is coordinated among a plurality of mesh network nodes to conserve power. A controller is synchronized with an existing wireless mesh network by sending a network synchronization signal from the controller indicating that sleep timing information is lost, and receiving a reply from one or more wireless mesh network nodes within the existing wireless mesh network comprising sleep timing information for the wireless mesh network.

Claims

1. A method of synchronizing a controller with an existing wireless mesh network, comprising:

sending a network synchronization signal from the controller indicating that sleep timing information is lost; and

receiving a reply from one or more wireless mesh network nodes within the existing wireless mesh network comprising sleep timing information for the wireless mesh network;

wherein the network synchronization signal comprises a sync pulse repeated at a higher than normal rate, wherein the higher than normal rate is such that the network synchronization signal is sent at least twice during a minimum wake period of the wireless mesh network nodes.

2. The method of synchronizing a controller with an existing wireless mesh network of claim 1, further comprising updating sleep timing information in the controller to bring the controller into sleep schedule synchronization with the wireless mesh network.

3. The method of synchronizing a controller with an existing wireless mesh network of claim 1, wherein the controller is coupled to a power line and the one or more wireless mesh network nodes are battery powered.

4. The method of synchronizing a controller with an existing wireless mesh network of claim 1, wherein sending a network synchronization signal from the controller indicating that sleep timing information is lost includes determining, within the controller, whether the controller has the correct sleep timing information for the existing wireless mesh network.

5. A mesh network controller, comprising:

a sleep module operable to coordinate sleeping among a plurality of mesh network nodes comprising a part of the mesh network to conserve power by coordinating sleep timing information among the mesh network nodes; and

a communications module operable to send a network synchronization signal from the controller indicating that sleep timing information is lost in the controller, and to receive a reply from one or more wireless mesh network nodes within the wireless mesh network comprising sleep timing information for the wireless mesh network;

wherein the network synchronization signal comprises a sync pulse repeated at a higher than normal rate, wherein the higher than normal rate is such that the network synchronization signal is sent at least twice during a minimum wake period of the wireless mesh network nodes.

6. The mesh network controller of claim 5, further comprising updating sleep timing information in the controller to bring the controller into sleep schedule synchronization with the wireless mesh network.

7. The mesh network controller of claim 5, wherein the controller is coupled to a power line.

8. The mesh network controller of claim 5, wherein the sleep module determines whether the sleep module has the correct sleep timing information for the mesh network.

9. A wireless mesh network node, comprising:

a sleep module operable to receive sleep timing information from a controller or other wireless mesh network node such that the node is operable to sleep to conserve battery power on a schedule coordinated among nodes in the wireless mesh network; and

a communications module operable to receive a network synchronization signal from the controller indicating that sleep timing information is lost in the controller, and to send a reply comprising sleep timing information for the wireless mesh network;

wherein the network synchronization signal comprises a sync pulse repeated at a higher than normal rate, wherein the higher than normal rate is such that the network synchronization signal is sent at least twice during a minimum wake period of the wireless mesh network node.

10. The wireless mesh network node of claim 9, wherein the mesh network node is battery powered.

11. A non-transitory machine-readable medium with instructions stored thereon, the instructions when executed operable to cause a wireless mesh network controller to:

coordinate sleeping among a plurality of mesh network nodes comprising a part of the mesh network to conserve power by coordinating sleep timing information among the mesh network nodes;

send a network synchronization signal from the controller indicating that sleep timing information is lost in the controller; and

receive a reply from one or more wireless mesh network nodes within the wireless mesh network comprising sleep timing information for the wireless mesh network;

wherein the network synchronization signal comprises a sync pulse repeated at a higher than normal rate, wherein the higher than normal rate is such that the network synchronization signal is sent at least twice during a minimum wake period of the wireless mesh network nodes.

12. The machine-readable medium of claim 11, the instructions when executed further operable to update sleep timing information in the controller to bring the controller into sleep schedule synchronization with the wireless mesh network.

13. The machine-readable medium of claim 11, wherein the controller determines if the controller has the correct sleep timing information for the wireless mesh network.