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

• US 7,580,995 B2
• Filed: 11/06/2006
• Issued: 08/25/2009
• Est. Priority Date: 01/12/2001
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Bahl, Paramvir
• Primary Examiner(s): BATES, KEVIN T
• Application Number:
  US11/557,054
• Publication Number:
  US 20070067434A1
• Time in Patent Office: 1,023 Days
• Field of Search: 709/223, 709/217, 455/403, 455/404.1, 455/456.1, 342/118, 342/126
• 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 system, comprising:

a server having memory;

a user database stored in the memory of the server, the user database containing a user field for storing a user name of a mobile computer user, and a last known location field for storing a most recent location of a computer user identified in a corresponding user field;

a wireless access point of a wireless local area network configured to receive RF network transmissions from one or more mobile computers;

a mobile computer having memory and a wireless network interface for RF communication with the wireless access point of the wireless local area network;

a location tracking system in the mobile computer memory configured to determine, based on a beacon packet'"'"'s signal strength received from the wireless access point and using a previously established radio map of locations inside a plurality of buildings and locations outside of the buildings, a location of the mobile computer;

a location manager in the mobile computer memory configured to periodically transmit the location of the mobile computer and the user name of a mobile computer user to the server via the wireless network interface, wherein the location manager transmits the location of the mobile computer in absolute coordinates; and

a computing unit having a computing unit location manager configured to search the user database of the server to determine information regarding the location of a mobile user.

2. The system as recited in claim 1, wherein the computing unit is a stationary computing unit.

3. The system as recited in claim 1, wherein the computing unit is a mobile computing unit.

4. The system as recited in claim 1, wherein:

the mobile computer further comprises a clock;

the location manager is further configured to transmit a time of transmission to the server together with the location and user name information; and

the user database further comprises a time field for storing the time that a transmission identifying the location of the mobile user and the user name of the mobile computer user is received from the mobile computer.

5. The system as recited in claim 1, wherein the user database further comprises an active field indicating if the mobile computer user has used the mobile computer within a specified time period.

6. The system as recited in claim 1, wherein the location manager transmits the location of the mobile computer in coordinates relative to a known absolute location.

7. The system as recited in claim 1, wherein the location manager transmits the location of the mobile computer as a geographic unit.

8. The system as recited in claim 1, wherein the location manager transmits the location of a network node with which the mobile computer is communicating as the location of the mobile computer.

9. The system as recited in claim 1, wherein:

the mobile computer is a first computer;

the system further comprises a second computer having a location manager;

the user database further comprises an active field;

the mobile computer user is logged onto both the first mobile computer and the second computer;

the location manager of the first computer and the location manager of the second computer are further configured to transmit an active signal for a specified period of time after the respective computers are used;

the active field corresponding to the first computer indicating the mobile computer user last used the first computer when the active signal is transmitted from the first computer;

the active field corresponding to the second computer indicating the mobile computer user last used the second computer when the active signal is transmitted from the second computer; and

only one active field indicating activity by the mobile computer user at any given time.

10. The system as recited in claim 1, wherein:

the user database further comprises an OK field that contains data that identifies one or more system users that are authorized to receive data regarding the location of the mobile computer user identified in the corresponding user field.

11. The system as recited in claim 1, wherein the location manager of the computing unit is further configured to:

search the user database to locate an entry for a specific user;

calculate a time differential between a current time and a time stored in the time field corresponding to the specific user if the specific user is found;

compare the time differential to a time threshold;

recognize the location contained in the last known location field corresponding to the specific user as the location of the specific user if the time differential is within the time threshold;

transmit a signal to cause the location manager of the mobile computer to invoke the location tracking system of the mobile computer if the time differential is not within the time threshold, to determine the location of the mobile computer and transmit location and user information to the server where it is stored in the user database; and

recognize the newly stored location contained in the last known location field corresponding to the specific user as the location of the specific user.

12. A method for locating a mobile computer user in a wireless network, comprising:

periodically identifying a location of a mobile computer that is used by a mobile user, wherein the location is determined in absolute coordinates, and associating a time stamp with the location indicating a time at which the location was identified, wherein the periodically identifying a location of a mobile computer further comprises identifying the location of the mobile user from a plurality of locations by measuring relative strengths of radio frequency transmissions emitted from a plurality of base stations and wherein the plurality of locations includes at least one location outside of a plurality of buildings and at least one location inside one of the buildings;

transmitting the location of the mobile computer to a network server together with the time stamp and a name of the mobile user;

storing the transmitted information on the network server;

receiving a request from a computing unit for the location of the mobile user;

determining the last known location of the mobile computer by accessing the network server and finding the location having a most recent time stamp; and

recognizing the last known location of the mobile computer as the location of the mobile user.

13. The method as recited in claim 12, wherein the periodically identifying a location of a mobile computer further comprises identifying the location of the mobile user by measuring relative strengths of radio frequency transmissions emitted from a plurality of base stations.

14. The method as recited in claim 12, further comprising:

transmitting an active signal together with the location information if the mobile user has actively used the mobile computer within a specified period of time.

15. A method comprising:

receiving, at a server of a wireless local area network and from a mobile computer within the wireless local area network, multiple locations of the mobile computer, at least one of the locations being outside of a plurality of buildings and least one of the locations being inside one of the buildings, each of the multiple locations being determined in absolute coordinates, and each of the multiple locations received at recurring time periods and determined using RF signals received from a plurality of RF beacons;

time-stamping each of the multiple locations based on the recurring time periods at which each of the multiple locations is received;

receiving, at the server, a request from a computing unit for a current location of a mobile computer user;

determining that the mobile computer user is identified with the mobile computer;

determining which of the multiple locations has a most-recent time-stamp; and

transmitting the location having the most-recent time-stamp to the computing unit.

16. The method of claim 15, wherein the server is integral with a wireless access point.