System and method for determining the mobility of nodes in a wireless communication network

• US 7,830,842 B2
• Filed: 12/21/2005
• Issued: 11/09/2010
• Est. Priority Date: 12/30/2004
• Status: Active Grant

• Current Assignee: Bison Patent Licensing, LLC
• Original Assignee: MeshNetworks, Inc. (Motorola Solutions, Inc.)
• Inventors: Ramachandran, Shyamal, Strutt, Guenael
• Primary Examiner(s): Ly, Nghi H
• Application Number:
  US11/314,219
• Publication Number:
  US 20060160540A1
• Time in Patent Office: 1,784 Days
• Field of Search: 370/338, 370/328, 455/441, 455/404.2, 455/456.1
• US Class Current: 370/338
• CPC Class Codes: G01S 11/06 using intensity measurements
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 64/006 with additional information processing, e.g. for direction or speed determination
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A system and method for determining the mobility of a node (102) in a wireless communication network (102). The system and method determine the distance between the node (102) and at least one stationary neighboring node (102, 106, 107) at at least two or more time points, using at least two moving average filters, to arrive at two distance values. The system and method then determine the relative velocity based on the at least two distance values, and thus determine whether the node (102) is mobile.

Claims

1. A method for determining mobility of a node in a wireless communication network, the method comprising within the node:

receiving mobility status information from a plurality of other nodes operating within the wireless communication network, wherein the mobility status information identifies each of the other nodes as either a mobile node or a stationary node;

measuring distance information representing a change in distance between the node and each of the stationary nodes in the wireless communication network; and

identifying the node as mobile when the node determines from the measured distance information that it is mobile before each of the other stationary nodes is identified as mobile.

2. A method as claimed in claim 1, further comprising:

periodically performing each of the receiving, measuring, and identifying steps.

3. A method as claimed in claim 1, further comprising:

operating the node to transmit information indicating whether the node is identified as mobile or stationary.

4. A method as claimed in claim 1, further comprising:

mathematically processing the distance information to generate the change in distance value.

5. A method as claimed in claim 4, wherein:

the change in distance value represents a relative velocity between the node and the other node; and

the identifying step comprises identifying the node as mobile or stationary based on the relative velocity and the information received from the other node.

6. A method as claimed in claim 1, wherein:

the identifying step comprises determining a likelihood that the node is stationary based on an average of relative velocities of the node with respect to the other nodes and a skewness of the average of the relative velocities, and determining whether to identify the node as stationary based on the determined likelihood.

7. A method as claimed in claim 1, wherein:

the identifying step comprises setting a value for a verification time based on a likelihood that the node is stationary, and assessing whether the node is stationary or mobile during the verification time.

19. The method of claim 1, further comprising:

identifying the node as being mobile relative to at least one or more other stationary nodes;

setting an expiration timer proportional to a probability of the node being mobile relative to at least one or more other stationary nodes; and

determining that the node is mobile if, by the time the timer has expired, the node has not received notice from the at least one stationary node that it is no longer stationary.

20. The method of claim 19, wherein the probability is proportional to a relative velocity of the node relative to all other stationary nodes.

8. A method for determining mobility of a node in a wireless communication network, the method comprising:

operating the node to receive respective information from each of a plurality of other nodes in the network, each respective information indicating whether the respective other node is identified as a mobile node or a stationary node;

operating the node to determine its respective relative velocity with respect to each of a plurality of other nodes in the network; and

operating the node to determine whether it should be identified as mobile or stationary based on the respective relative velocities and the respective information.

9. A method as claimed in claim 8, wherein:

the node performs the operating steps to determine its respective velocity and to determine whether it should be identified as mobile or stationary at each time that the node receives the respective information from a respective other node.

10. A method as claimed in claim 8, further comprising:

operating the node to periodically determine whether it should remain identified as mobile or stationary.

11. A method as claimed in claim 8, further comprising:

operating the node to transmit information indicating that it is identified as mobile or stationary.

12. A node, for communication in a wireless network, comprising:

a transceiver; and

a controller, operating to control the transceiver to communicate with at least one other node in the wireless communication network including receiving mobility status information from a plurality of other nodes operating within the wireless communication network, wherein the mobility status information identifies each of the other nodes as either a mobile node or a stationary node, and further operating to measure distance information representing a change in distance between the node and the each of the stationary nodes in the wireless communication network, and to identify the node as mobile when the node determines from the measured distance information that it is mobile before each of the other stationary nodes is identified as mobile.

13. A node as claimed in claim 12, wherein:

the controller further operates to control the transceiver to periodically communicate with the other node; and

the controller further operates to periodically repeat the receiving, measuring, and identifying operations.

14. A node as claimed in claim 12, wherein:

the controller further operates to control the transceiver to transmit information indicating whether the node is identified as mobile or stationary.

15. A node as claimed in claim 12, wherein:

the controller further operates to mathematically process the distance information to generate the change in distance value.

16. A node as claimed in claim 15, wherein:

the change in distance value represents a relative velocity between the node and the other node; and

the controller further operates to identify the node as mobile or stationary based on the relative velocity and the information received from the other node.

17. A node as claimed in claim 12, wherein:

the controller operates to determine a likelihood that the node is stationary based on an average of relative velocities of the node with respect to the other nodes and a skewness of the average of the relative velocities, and determine whether to identify the node as stationary based on the determined likelihood.

18. A node as claimed in claim 12, wherein:

the controller operates to set a value for a verification time based on a likelihood that the node is stationary, and assess whether the node is stationary or mobile during the verification time.