Systems and methods for locating mobile computer users in a wireless network

• US 7,133,909 B2
• Filed: 01/12/2001
• Issued: 11/07/2006
• Est. Priority Date: 01/12/2001
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Bahl, Paramvir
• Primary Examiner(s): Barot, Bharat
• Assistant Examiner(s): Bates, Kevin T
• Application Number:
  US09/760,180
• Publication Number:
  US 20020095486A1
• Time in Patent Office: 2,125 Days
• Field of Search: 709/217, 709/223, 709/200, 455/403, 455/404.1, 455/456.1, 701/300
• US Class Current: 709/223
• CPC Class Codes: H04L 67/52 specially adapted for the location of the user terminal
• CPC Class Codes: H04L 67/535 Tracking the activity of the user network monitoring arrangements H04L43/00; recording of computer activity G06F11/34
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

System and methods for locating a computer user are described wherein the computer either periodically updates a network server with its location, or updates the network server when asked by the server to do so. The network server can be a mobile computer. The user'"'"'s computer determines its physical location using a location tracker service and then transmits this location information to the server, which stores it in its memory. The information stored includes the physical location of the computer, the time when the location was identified, a name identifying the user of the computer, and an indicator, which indicates whether or not the user was active on the computer during a specified time interval prior to the transmission. The location of the user is deemed to be the last known location of the computer used by the user. If the user is logged onto more than one computer, the location of the user is deemed to be the last known location of the computer that indicates the user as being active.

Claims

1. A method, comprising:

determining an absolute location of a mobile computing unit, wherein the act of determining the absolute location comprises receiving RF signals and a plurality of RF beacons having known locations and using environmental profiling to establish the absolute location of the mobile computing unit;

periodically transmitting, from the mobile computing unit, the location of the mobile computing unit to a network server together with a user name of a user using the mobile computing unit; and

including an active signal with the periodically transmitted information when the user is actively using the mobile computing unit.

2. The method as recited in claim 1, wherein the network server is a wireless network server.

3. The method as recited in claim 1, further comprising time-stamping the transmission to the network server and transmitting the time stamp with the transmitted information.

4. The method as recited in claim 1, wherein the user actively using the mobile computing unit further comprises the user having used the computing unit to within a pre-defined time period.

5. The method as recited in claim 1, wherein transmitting the absolute location of the mobile computer unit to a network server only occurs upon a request from the network server for the mobile computer unit to update the absolute location of the computer unit.

6. The method as recited in claim 1, further comprising encrypting the absolute location of the mobile computing unit prior to transmitting the absolute location of the computing unit to the network server.

7. A mobile computing unit, comprising:

memory;

a wireless network interface configured to connect the mobile computing unit to multiple wireless access points of one or more remote servers;

a location tracking service configured to determine an absolute location of the mobile computer unit utilizing a radio frequency system capable of determining the absolute location by detecting signals transmitted from multiple wireless access points; and

a location manager configured to periodically transmit the absolute location of the mobile computing unit to one or more of the remote servers via the wireless network interface.

8. The mobile computing unit as recited in claim 7, wherein the location manager is further configured to transmit a user name of a user logged onto the mobile computing unit to one or more of the remote servers together with the absolute location of the mobile computing unit.

9. The mobile computing unit as recited in claim 7, wherein the location manager is further configured to transmit an active signal to one or more of the remote servers together with the absolute location of the mobile computing unit when a user logged onto the mobile computing unit has actively used the unit within a specified period of time.

10. The mobile computing unit as recited in claim 7, further comprising a clock, and wherein the location manager is further configured to time-stamp the transmission of the location information with a time that the transmission is sent.

11. The mobile computing unit as recited in claim 7, wherein the location manager identifies and transmits the absolute location of a network node with which the mobile computing unit is communicating as the absolute location of the mobile computing unit.

12. The mobile computing unit as recited in claim 7, wherein the location manager is configured to invoke the location tracking service when commanded to do so by a second computing unit or one or more of the remote servers.

13. The mobile computing unit as recited in claim 7, wherein the location manager is further configured to encrypt the absolute location of the mobile computing unit before transmitting the absolute location of the mobile computing unit to one or more of the remote servers.

14. A method comprising:

receiving radio frequency transmissions emitted from a plurality of radio frequency base stations of a wireless local area network;

measuring relative strengths of the radio frequency transmissions;

determining an absolute location of a mobile computing device based on the relative strengths;

identifying the absolute location of the mobile computing device as that of a computer user;

receiving a request for the absolute location of the computer user from a computing unit; and

transmitting the absolute location of the computer user to the computing unit.

15. The method of claim 14, wherein the acts of receiving the radio frequency transmissions, measuring the relative strengths, and determining the absolute location are performed by the mobile computing device.

16. The method of claim 14, wherein the act of identifying the absolute location of the mobile computing device as that of the computer user comprises receiving from the mobile computing device an identifier associated with the computer user.

17. The method of claim 14, wherein the act of identifying the absolute location of the mobile computing device as that of the computer user comprises calculating a time differential between a time stamp associated with the absolute location of the mobile computing device and a current time, comparing the time differential with a predetermined time threshold, and defining the absolute location of the mobile computing device as that of the computer user if the time differential is less than the time threshold.

18. The method of claim 14, further comprising:

receiving an active signal indicating that the computer user has actively used the mobile computing device within a specified period of time, and wherein the act of identifying the absolute location comprises defining the absolute location of the mobile computing device as that of the computer user if the active signal has been received within a predetermined period of time.