Collaboratively locating disconnected clients and rogue access points in a wireless network

• US 7,317,914 B2
• Filed: 01/31/2005
• Issued: 01/08/2008
• Est. Priority Date: 09/24/2004
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Bahl, Paramvir, Chandra, Ranveer, Adya, Atul, Qiu, Lili
• Primary Examiner(s): Perez-Gutierrez; Rafael
• Assistant Examiner(s): GONZALEZ, AMANCIO
• Application Number:
  US11/047,022
• Publication Number:
  US 20060068811A1
• Time in Patent Office: 1,072 Days
• Field of Search: 455/456.1, 455/456.2, 455/67.11, 702/150
• US Class Current: 455/421
• CPC Class Codes: H04W 12/122 Counter-measures against attacks; Protection against rogue devices
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

Methods are described for using collaboration of neighboring wireless devices to enable location of disconnected wireless devices and rogue wireless access points. A central server computes the locations of the neighboring clients and uses those locations to estimate the location of a disconnected client. These techniques may take advantage of the beaconing and probing mechanisms of IEEE 802.11 to ensure that connected clients do not pay unnecessary overheads for detecting disconnected clients. Methods are also described for detecting and locating rogue devices by collaboratively collecting information from neighboring devices and comparing the information to a database.

Claims

1. A computer-readable medium including computer-executable instructions for determining the location of a first wireless client that is unable to connect to an infrastructure network, the computer-executable instructions executing on one or more other wireless clients connected to the infrastructure network and located in the vicinity of the first client, and performing the steps of:

receiving one or more signals from the first client;

determining that the one or more received signals comprise signals indicating that the first client is unable to connect to the infrastructure network;

recording the signal strength of the one or more received signals; and

transmitting the recorded signal strength information to a diagnostic server for estimating the location of the first client,

wherein the diagnostic server estimates the location of the first client by performing the steps of;

receiving the transmitted signal strength information;

computing estimates of the locations of the one or more other wireless clients; and

approximating the location of the first client using the received signal strength information and the computed estimates of the locations of the one or more other wireless clients.

2. The computer-readable medium of claim 1 wherein the location of the first client is approximated to within about twelve meters.

3. The computer-readable medium of claim 1 wherein the location of the first client approximately corresponds to an RF hole.

7. The method of claim 1, wherein the one or more received signals comprise beacon signals.

8. The method of claim 1, wherein the infrastructure network operates according to the IEEE 802.11 protocol.

4. A method for determining the location of a first wireless client that is unable to connect to an infrastructure network, the method comprising:

receiving at one or more other wireless clients one or more signals transmitted from the first client;

determining that the one or more received signals comprise signals indicating that the first client is unable to connect to the infrastructure network;

recording at the one or more other wireless clients the signal strength of the one or more received signals;

transmitting the recorded signal strength information from the one or more other wireless clients to a diagnostic server;

receiving at the diagnostic server the transmitted signal strength information;

computing at the diagnostic server estimates of the locations of the one or more other wireless clients; and

approximating at the diagnostic server the location of the first client using the received signal strength information and the computed estimates of the locations of the one or more other wireless clients.

5. The method of claim 4 wherein the location of the first client is estimated to within about twelve meters.

6. The method of claim 4 wherein the location of the first client approximately corresponds to an RF hole.

9. The method of claim 4, wherein the one or more received signals comprise beacon signals.

10. The method of claim 4, wherein the infrastructure network operates according to the IEEE 802.11 protocol.