METHODS AND APPARATUS FOR LOCATING A MOBILE DEVICE IN A SLEEP MODE

• US 20100110948A1
• Filed: 10/31/2008
• Published: 05/06/2010
• Est. Priority Date: 10/31/2008
• Status: Active Grant

• Current Assignee: Extreme Networks, Inc.
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: BATTA, Puneet
• Granted Patent: US 8,391,169 B2
• Time in Patent Office: Days
• US Class Current: 370/311
• CPC Class Codes: G01S 11/06 using intensity measurements
• CPC Class Codes: G01S 5/0027 of actual mobile position, i.e. position determined on mobile
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04W 52/0235 where the received signal is a power saving command
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Apparatus and methods are provided for locating a mobile device in a sleep mode. A method comprises transmitting a beacon signal configured to initiate transmission of a response signal from a mobile device in a sleep mode. The mobile device is associated with a first wireless access device on a first communication channel. The method further comprises receiving the response signal from the mobile device on the first communication channel and determining the physical location of the mobile device based on the response signal.

Claims

1. A method for locating a mobile device being initially in a sleep mode, the method comprising:

waking the mobile device from the sleep mode, wherein the mobile device transmits a frame in response to waking;

receiving the frame by a plurality of wireless access devices; and

determining a location of the mobile device based on a respective characteristic for the frame received at each wireless access device of the plurality of wireless access devices.

2. The method of claim 1, the mobile device being associated with a first wireless access device of the plurality of wireless access devices, wherein waking the mobile device comprises transmitting a beacon frame from the first wireless access device, the beacon frame being configured such that a traffic information map associated with the mobile device indicates pending data for the mobile device.

3. The method of claim 1, the mobile device being associated with a first wireless access device of the plurality of wireless access devices on a first channel, wherein the method further comprises configuring the plurality of wireless access devices for receiving data on the first channel.

4. The method of claim 3, wherein configuring the plurality of wireless access devices for receiving data on the first channel comprises:

configuring a second wireless access device of the plurality of wireless access devices for receiving data on the first channel; and

configuring a third wireless access device of the plurality of wireless access devices for receiving data on the first channel.

5. The method of claim 1, the mobile device being associated with a first wireless access device of the plurality of wireless access devices on a first channel, the first wireless access device receiving the frame with a first signal strength, wherein the method further comprises:

identifying a second wireless access device of the plurality of wireless access devices for communication on the first channel;

configuring the second wireless access device for receiving data on the first channel, wherein the second wireless access device receives the frame with a second signal strength; and

determining the location of the mobile device comprises determining the location of the mobile device based at least in part on the first signal strength and the second signal strength.

6. The method of claim 1, further comprising returning the mobile device to the sleep mode after the mobile device transmits the frame.

7. The method of claim 6, wherein returning the mobile device to the sleep mode comprises responding to the frame such that the mobile device returns to the sleep mode.

8. The method of claim 1, further comprising identifying a first wireless access device of the plurality of wireless access devices, the first wireless access device being associated with the mobile device on a first channel, wherein waking the mobile device comprises indicating pending data for the mobile device from the first wireless access device.

9. The method of claim 8, wherein indicating pending data comprises transmitting a beacon frame from the first wireless access device, the beacon frame including a traffic information map, wherein the traffic information map associated with the mobile device is configured to notify the mobile device of data awaiting delivery to the mobile device.

10. A method for determining a physical location of a mobile device, wherein the mobile device is associated with a first wireless access device on a first communication channel, the method comprising:

transmitting, at a first time, a beacon signal, the beacon signal being configured to initiate transmission of a response signal from the mobile device, wherein the mobile device is in a power save mode at the first time;

receiving the response signal from the mobile device on the first communication channel; and

determining the physical location of the mobile device based on the response signal.

11. The method of claim 10, wherein transmitting the beacon signal comprises transmitting the beacon signal from the first wireless access device, the beacon signal being configured to indicate pending data for the mobile device.

12. The method of claim 11, wherein transmitting the beacon signal from the first wireless access device comprises configuring a traffic information map associated with the mobile device to indicate pending data for the mobile device.

13. The method of claim 10, wherein:

receiving the response signal comprises receiving the response signal from the mobile device on the first communication channel at a plurality of locations; and

determining the physical location comprises determining the physical location of the mobile device based on a characteristic of the response signal for each location of the plurality of locations.

14. The method of claim 13, the first wireless access device having a first location, wherein the method further comprises:

identifying a second wireless access device for communication on the first communication channel, the second wireless access device having a second location; and

configuring the second wireless access device for receiving data on the first communication channel, the second wireless access device receiving the response signal on the first communication channel, wherein determining the physical location of the mobile device comprises determining the physical location of the mobile device based on a characteristic of the response signal at the first location and a characteristic of the response signal at the second location.

15. The method of claim 14, wherein identifying the second wireless access device comprises determining a wireless access device of a plurality of wireless access devices for communication on the first communication channel based on a selection criterion.

16. The method of claim 10, the first wireless access device having a first antenna and a second antenna, wherein:

receiving the response signal comprises;

receiving the response signal at the first antenna at a second time; and

receiving the response signal at the second antenna at a third time; and

determining the physical location of the mobile device comprises determining the physical location of the mobile device based at least in part on a difference between the second time and the third time.

17. A wireless switch for a wireless network having a plurality of wireless access devices, wherein a mobile device is associated with a first wireless access device of the plurality of wireless access devices on a first channel, the wireless switch comprising:

a communication module, the communication module being configured to communicate with the plurality of wireless access devices;

a database, the database being configured to maintain physical location information for each wireless access device of the plurality of wireless access devices; and

a processor coupled to the communication module and the database, wherein the processor is configured to;

wake up the mobile device from a sleep mode, wherein the first wireless access device receives a response signal from the mobile device having a first characteristic;

configure a second wireless access device for receiving data on the first channel, wherein the second wireless access device receives the response signal having a second characteristic; and

determine a physical location of the mobile device based at least in part on a physical location of the first wireless access device, a physical location of the second wireless access device, the first characteristic, and the second characteristic.

18. The wireless switch of claim 17, wherein the processor is configured to wake up the mobile device by initiating transmission of a beacon signal from the first wireless access device, the beacon signal being configured to wake up the mobile device from the sleep mode.

19. The wireless switch of claim 17, wherein the processor is configured to configure a third wireless access device for receiving data on the first channel, wherein the third wireless access device receives the response signal having a third characteristic.

20. The wireless switch of claim 19, wherein the processor is configured to determine the physical location of the mobile device by triangulating the physical location of the mobile device based on the first characteristic, the second characteristic, the third characteristic, the physical location of the first wireless access device, the physical location of the second wireless access device, and a physical location of the third wireless access device.