Wireless network range estimation and associated methods

• US 7,778,651 B2
• Filed: 02/16/2005
• Issued: 08/17/2010
• Est. Priority Date: 02/16/2005
• Status: Active Grant

• Current Assignee: Nera Innovations Limited (Atlantic IP Services Limited)
• Original Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Inventors: Billhartz, Thomas Jay
• Primary Examiner(s): Kincaid, Lester
• Assistant Examiner(s): Zewari, Sayed T
• Application Number:
  US11/058,931
• Publication Number:
  US 20060183488A1
• Time in Patent Office: 2,008 Days
• Field of Search: 455/456.5, 455/456.1, 455/456.2, 455/456.3, 455/414.2, 455/421, 455/440
• US Class Current: 455/456.5
• CPC Class Codes: G01S 13/765 with exchange of information between interrogator and responder
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 40/00 Communication routing or communication path finding

Abstract

The wireless communications system includes a plurality of wireless communications devices, with each device type having a known latency profile associated therewith. A wireless device detector includes a controller for cooperating with a transceiver for transmitting a plurality of device finding signals to a target wireless communications device. The target wireless communications device transmits a respective reply signal for each of the device finding signals. Also, the controller generates an observed latency profile for the target wireless communications device based upon the transmission of device finding signals and the received reply signals therefor, determines a propagation delay based upon the observed latency profile and the known latency profile, and estimates a range to the target wireless communications device based upon the determined propagation delay.

Claims

1. A wireless communications system comprising:

a plurality of wireless communications devices, each wireless communications device having a device type associated therewith from among a plurality of different device types and having a unique identifier (UID) associated therewith, and each device type having a known latency profile associated therewith; and

a wireless device detector comprising

at least one antenna and a transceiver connected thereto, and

a controller for cooperating with said transceiver for transmitting a plurality of device finding signals to a target wireless communications device from among said plurality of wireless communications devices and for inserting the UID for said target wireless communications device in each of said device finding signals;

said target wireless communications device transmitting a respective reply signal for each of said device finding signals based upon the UID in the device finding signals;

said controller of said wireless device detector also for

cooperating with said transceiver for receiving the reply signals,

generating an observed latency profile for said target wireless communications device based upon the transmission of device finding signals and the received reply signals therefor,

determining a propagation delay associated with said target wireless communications device based upon the observed latency profile and the known latency profile of said target wireless communications device, and

estimating a range to said target wireless communications device based upon the determined propagation delay.

2. The wireless communications system of claim 1 wherein the known latency profile and the observed latency profile of each device comprise histograms;

and wherein said controller determines the propagation delay based upon a mathematical cross-correlation of the respective histograms.

3. The wireless communications system of claim 1 wherein said target wireless communications device generates unsolicited signals including the UID thereof;

wherein said controller cooperates with said transceiver to receive at least one unsolicited signal from said target device; and

wherein said controller determines the UID for said target wireless communications device from the at least one unsolicited signal.

4. The wireless communications system of claim 3 wherein said controller determines the device type of said target wireless communications device based upon the UID thereof.

5. The wireless communications system of claim 4 wherein the UIDs comprise media access control (MAC) addresses of respective wireless communications devices, and wherein said controller determines the device type of said target wireless communications device based upon the MAC address thereof.

6. The wireless communications system of claim 1 wherein the wireless device detector further comprises a profile database for storing respective known latency profiles associated with each of the plurality of different device types.

7. The wireless communications system of claim 1 wherein said controller determines the device type of the target wireless communications device based upon the observed latency profile.

8. The wireless communications system of claim 7 wherein the wireless device detector further comprises a profile database for storing respective known latency profiles associated with each of the plurality of different device types.

9. The wireless communications system of claim 1 wherein said wireless device detector further comprises a portable housing carrying said at least one antenna, said transceiver, and said controller.

10. The wireless communications system of claim 1 wherein said wireless communications devices comprise wireless local area network (WLAN) devices.

11. The wireless communications system of claim 1 wherein said wireless communications devices comprise mobile ad-hoc network (MANET) devices.

12. The wireless communications system of claim 1 wherein said wireless communications devices comprise cellular communications devices.

13. A wireless communications system comprising:

a plurality of wireless local area network (WLAN) devices, each WLAN device having a device type associated therewith from among a plurality of different device types and having a unique identifier (UID) associated therewith, and each device type having a known latency histogram associated therewith; and

a wireless device detector comprising

at least one antenna and a transceiver connected thereto, and

a controller for cooperating with said transceiver for transmitting a plurality of device finding signals to a target WLAN device from among said plurality of WLAN devices and for inserting the UID for the target WLAN device in each of the device finding signals;

said target WLAN device transmitting a respective reply signal for each of said device finding signals based upon the UID in the device finding signals;

said controller of said wireless device detector also for

cooperating with said transceiver for receiving the reply signals,

generating an observed latency histogram for said target WLAN device based upon the transmission of device finding signals and the received reply signals therefor,

determining a propagation delay associated with said target WLAN device based upon a mathematical cross-correlation of the observed latency histogram and the known latency histogram of said target WLAN device, and

estimating a range to said target WLAN device based upon the determined propagation delay.

14. The wireless communications system of claim 13 wherein the wireless device detector further comprises a profile database for storing respective known latency histograms associated with each of the plurality of different device types.

15. The wireless communications system of claim 13 wherein said controller determines the device type of the target wireless communications device based upon the observed latency histogram.

16. A wireless device detector for detecting a target wireless communications device, each wireless communications device having a unique identifier (UID) associated therewith, the wireless device detector comprising:

at least one antenna and a transceiver connected thereto; and

a controller for

cooperating with said transceiver for transmitting a plurality of device finding signals to the target wireless communications device, each device finding signal having the UID for the target wireless communications device inserted therein, and receiving a respective reply signal therefrom for each of said device finding signals based upon the UID in the device finding signals,

generating an observed latency profile for said target wireless communications device based upon the transmission of device finding signals and the received reply signals therefor,

determining a propagation delay associated with said target wireless communications device based upon the observed latency profile and a known latency profile of said target wireless communications device, and

estimating a range to said target wireless communications device based upon the determined propagation delay.

17. The wireless device detector of claim 16 wherein the known latency profile and the observed latency profile comprise histograms;

and wherein said controller determines the propagation delay based upon a mathematical cross-correlation of the respective histograms.

18. The wireless device detector of claim 16 further comprising a profile database for storing respective known latency profiles associated with a plurality of different device types.

19. The wireless device detector of claim 18 wherein said controller determines the device type of the target wireless communications device based upon the observed latency profile.

20. The wireless device detector of claim 16 further comprising a portable housing carrying said at least one antenna, said transceiver, and said controller.

21. A method for locating a target wireless communications device from among a plurality of wireless communications devices, each wireless communications device having a device type associated therewith from among a plurality of different device types and having a unique identifier (UID) associated therewith, and each device type having a known latency profile associated therewith, the method comprising:

transmitting a plurality of device finding signals to the target wireless communications device, inserting the UID for the target wireless communications device in each of the device finding signals, and receiving a respective reply signal for each of the device finding signals therefrom, the respective reply signal being based upon the UID in the device finding signals;

generating an observed latency profile for the target wireless communications device based upon the transmission of device finding signals and the received reply signals therefor;

determining a propagation delay associated with the target wireless communications device based upon the observed latency profile and a known latency profile of the target wireless communications device; and

estimating a range to the target wireless communications device based upon the determined propagation delay.

22. The method of claim 21 wherein the known latency profile and the observed latency profile comprise histograms;

and wherein the propagation delay is determined based upon the mathematical cross-correlation of the respective histograms.

23. The method of claim 21 further comprising storing respective known latency profiles associated with the plurality of different device types.

24. The method of claim 21 further comprising determining the device type of the target wireless communications device based upon the observed latency profile.