Node control in wireless sensor networks

• US 20070097895A1
• Filed: 10/31/2005
• Published: 05/03/2007
• Est. Priority Date: 10/31/2005
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Venkatraman, Lakshmi, Keshavarzian, Abtin
• Granted Patent: US 7,978,666 B2
• Time in Patent Office: Days
• US Class Current: 370/311
• CPC Class Codes: H04W 52/0219 where the power saving management affects multiple terminals
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Network node control is described that includes node wakeup scheduling that reduces the energy consumption of levels of nodes and reduces the delay of information transfer through the network. The node wakeup scheduling includes a crossed ladder pattern that combines two wakeups in one level. The node wakeup scheduling also includes an adaptive version of the crossed ladder pattern that changes the wakeup patterns of the crossed ladder over time to provide uniform energy savings. The network node control also includes the use of multiple trees to transfer information through a network. This multi-parent node assignment assigns multiple parents with different wakeup schedules to each node in the network. This multi-parent assignment reduces the delay in transmission of information through the network and also increases energy efficiency in the nodes.

Claims

1. A method comprising sequentially controlling nodes of a network into an active state from an inactive state, wherein the nodes of the network include a plurality of nodes and a crossing node, wherein sequentially controlling includes placing each node of the plurality of nodes in the active state at least twice during a time period and placing the crossing node in the active state once during the time period, wherein sequentially controlling includes staggering initiation of the active state for the nodes.

2. The method of claim 1, wherein staggering initiation of the active state for the nodes further comprises using a time difference between initiation of the active state for each of the nodes.

3. The method of claim 1, wherein sequentially controlling further comprises controlling the initiation of the active state according to a pattern.

4. The method of claim 3, further comprising alternating the pattern among a plurality of patterns according to an adaptive time period.

5. The method of claim 4, wherein the pattern controls the nodes so that a different one of the nodes is the crossing node during different adaptive time periods.

6. A method comprising:

dividing a plurality of nodes of a network into a plurality of groups;

assigning to each node of the plurality of nodes a parent node from each of the plurality of groups, wherein the parent node watches over a node to which the parent node is assigned; and

controlling the plurality of nodes into an active state by alternately placing nodes into an active state according to the group to which the node is assigned.

7. The method of claim 6, wherein dividing further comprises placing a node having a plurality of connections to other nodes in the network in one of a first group and a second group.

8. The method of claim 7, wherein controlling further comprises alternately placing nodes of the first group and the second group into the active state.

9. The method of claim 7, wherein dividing further comprises placing a node having one connection to another node in the network in a third group.

10. The method of claim 9, wherein controlling further comprises placing nodes of the third group into the active state approximately simultaneously with the placing of nodes of the first group and the second group into the active state.

11. The method of claim 6, further comprising:

receiving a message at a base station and determining a destination node of the message;

determining a group to which the destination node belongs; and

transferring the message through the network via nodes of the group to which the destination node belongs.

12. The method of claim 6, further comprising:

identifying a node having a message for transmission through the network to a base station;

identifying a parent node of the identified node that is the next parent node to be placed into the active state; and

transferring the message to the identified parent node.

13. The method of claim 6, wherein controlling the plurality of nodes into an active state further comprises sequentially placing the nodes into an active state from an inactive state, wherein the plurality of nodes consists of a set of nodes and a crossing node, wherein controlling includes placing each node of the set of nodes in the active state at least twice during a time period and placing the crossing node in the active state once during the time period.

14. The method of claim 6, wherein alternately placing nodes into an active state includes staggering initiation of the active state for the nodes.

15. A system comprising:

a plurality of nodes, wherein at least one node of the plurality of nodes is coupled to at least one other node of the plurality of nodes to form at least one network;

a crossing node that is coupled to at least one of the plurality of nodes, wherein the crossing node is a member of the at least one network; and

a controller coupled to at least one of the plurality of nodes and the crossing node, the controller configured to sequentially control the plurality of nodes and the crossing node into an active state from an inactive state, wherein sequentially controlling includes placing each node of the plurality of nodes in the active state at least twice during a time period and placing the crossing node in the active state once during the time period, wherein sequentially controlling includes staggering initiation of the active state for the plurality of nodes and the crossing node.

16. The system of claim 15, wherein the controller is further configured so that staggering initiation of the active state for the plurality of nodes and the crossing node further comprises using a time difference between initiation of the active state for each of the plurality of nodes and the crossing node.

17. The system of claim 15, wherein the controller is further configured so that sequentially controlling further comprises controlling the initiation of the active state according to a pattern.

18. The system of claim 17, wherein the controller is further configured to alternate the pattern among a plurality of patterns according to an adaptive time period, wherein the pattern controls the nodes so that a different one of the nodes is the crossing node during different adaptive time periods.

19. A system comprising:

a plurality of nodes, wherein at least one node of the plurality of nodes is coupled to at least one other node of the plurality of nodes to form at least one network, wherein the plurality of nodes is divided into a plurality of groups, wherein a parent node from each of the plurality of groups is assigned to each node of the plurality of nodes, wherein the parent node watches over a node to which the parent node is assigned; and

a controller coupled to at least one of the plurality of nodes, the controller configured to control the plurality of nodes into an active state by alternately placing nodes into an active state according to the group to which the node is assigned.

20. The system of claim 19, wherein the plurality of nodes is divided by placing a node having a plurality of connections to other nodes in the network in one of a first group and a second group, wherein controlling further comprises alternately placing nodes of the first group and the second group into the active state.

21. The system of claim 20, wherein the plurality of nodes is divided by placing a node having one connection to another node in the network in a third group, wherein controlling further comprises placing nodes of the third group into the active state approximately simultaneously with the placing of nodes of the first group and the second group into the active state.

22. The system of claim 19, wherein one or more of the plurality of nodes and the controller is configured to receive a message at a base station and determine a destination node of the message, determine a group to which the destination node belongs, and transfer the message through the network via nodes of the group to which the destination node belongs.

23. The system of claim 19, wherein one or more of the plurality of nodes and the controller is configured to identify a node having a message for transmission through the network to a base station, identify a parent node of the identified node that is the next parent node to be placed into the active state, and transfer the message to the identified parent node.