Dynamic frequency selection and radar detection with a wireless LAN

• US 7,155,230 B2
• Filed: 08/19/2002
• Issued: 12/26/2006
• Est. Priority Date: 08/19/2002
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Tsien, Chih C.
• Primary Examiner(s): Nguyen, Duc M.
• Application Number:
  US10/223,251
• Publication Number:
  US 20040033789A1
• Time in Patent Office: 1,590 Days
• Field of Search: 455/450, 455/452.1, 455/452.2, 455462-464, 455/465, 455/426.1, 455/426.2, 455/423, 455/424, 455/63.1, 455/63.3, 455/67.11, 455/67.13, 455/500, 455/501, 455/507, 455/509, 455/62, 455/226.1, 455/226.2, 455/296, 455/334, 455/336, 455/337, 342/57, 342/159
• US Class Current: 455/450
• CPC Class Codes: G01S 7/021 Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals
• CPC Class Codes: H04B 1/1027 assessing signal quality or detecting noise/interference for the received signal
• CPC Class Codes: H04K 2203/18 for wireless local area networks or WLAN
• CPC Class Codes: H04K 3/226 Selection of non-jammed channel for communication spectrum sharing arrangements H04W16/14; selection of wireless resources by user or terminal H04W72/02
• CPC Class Codes: H04K 3/822 by detecting the presence of a surveillance, interception or detection
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 36/06 Reselecting a communication resource in the serving access point
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A receiver in a wireless communication system detects a possibly interfering radar signal, and uses dynamic frequency selection to switch to a non-interfering channel. The power level and the channel of the radar signal may be detected. When a radar signal that exceeds a predetermined power level is detected, the receiver may be tuned until the channel of the radar signal matches the communication receiver channel. The communication receiver may then be tuned to a higher quality channel to mitigate or avoid interference between communication signals and the radar signal.

Claims

1. An apparatus, comprising:

a wireless local area network device, said wireless local area network device to operate at a frequency of about 2 GHz to about 5 GHz; and

a dynamic frequency selection receiver disposed in said wireless local area device, said dynamic frequency selection receiver comprising;

a receiver input stage;

a communication receiver, said communication receiver includes a down-converter and an receiver signal strength indicator unit; and

a radar receiver coupled to said receiver input stage, said radar receiver includes a peak detector and a comparator, the comparator to compare a radar signal passed from a receiver input stage through said peak detector to said comparator with a reference signal to detect a radar signal having a predetermined power level, said radar receiver further including a video detector, a pulse shaper, and said receiver signal strength indicator unit indicates a quality of a channel of said communication receiver, said communication receiver to select a higher quality channel when the radar signal having a predetermined power level is detected.

2. An apparatus as claimed in claim 1, said radar receiver includes a pulse delay unit to provide a delayed version of the radar signal from the peak detector to the comparator.

3. An apparatus as claimed in claim 1, said radar receiver includes a pulse delay unit to provide a delayed version of the radar signal from the peak detector to the comparator, the pulse delay unit to provide a delay to the radar signal to match a delay of said communication receiver.

4. An apparatus as claimed in claim 1, said radar receiver includes a pulse delay unit to provide a delayed version of the radar signal from the peak detector to the comparator, the pulse delay unit being programmable to provide a delay to the radar signal to match a delay of said communication receiver.

5. An apparatus as claimed in claim 1, said radar receiver further comprising an AND gate, the AND gate to receive a radar signal passed through said communication receiver through the video detector and the pulse shaper, the AND gate to indicate that a channel of the radar signal channel is the same as a channel of said communication receiver selected by the down converter.

6. An apparatus comprising:

a receiver front end;

a communication receiver having a down-converter and a receiver signal strength indicator unit; and

a radar receiver having a peak detector, a pulse delay unit, and a comparator, the pulse delay unit to receive a radar signal from the peak detector and to provide a delay to the radar signal to match a delay of said communication receiver, the comparator to receive the delayed version of the radar signal from the pulse delay unit and to compare said delayed version with a reference signal to detect a radar signal having at least a predetermined power level, and said receiver signal strength indicator unit to indicate a quality of a channel of said communication receiver, said communication receiver to select a higher quality channel when the radar signal having at least the predetermined power level is detected.

7. The apparatus of claim 6, wherein the pulse delay unit is programmable to provide the delay to the radar signal to match the delay of said communication receiver.

8. An apparatus comprising:

a receiver front end;

a communication receiver having a down-converter and a receiver signal strength indicator unit;

a radar receiver having

a peak detector to receive a radar signal from the receiver front end;

a comparator coupled to the peak detector and configured to receive the radar signal to compare the received radar signal to a reference signal to detect a radar signal having at least the predetermined power level, and

a video detector, a pulse shaper, and an AND gate coupled to one another and configured to receive a radar signal passed through the communication receiver and to indicate that a channel of the radar signal is the same as a channel of said communication receiver selected by the down converter; and

said receiver signal strength indicator unit configured to indicate a quality of a channel of said communication receiver, said communication receiver to select a higher quality channel when the radar signal having at least the predetermined power level is detected.

9. A method comprising:

detecting a presence of a radar signal by delaying a received signal by a predetermined delay to match a delay of a communication receiver, and comparing a level of the delayed received signal to a reference level to determine when the delayed received signal has a power level greater than a predetermined power level;

determining a channel on the radar signal by sweeping a channel of a communication receiver until the channel of the communication receiver matches the channel of the radar signal; and

switching the channel of the communication receiver to another channel.

10. An apparatus comprising:

a front end to receive a radar signal;

a communication receiver coupled to the front end and having a first processing chain;

a radar receiver coupled to the front end and having a second processing chain, which is at least partially parallel to the first processing chain, configured to determine that the radar signal has a power level of at least a predetermined power level and to cooperate with the communication receiver to detect one or more channels on which the radar signal is received based at least in part on said determining that the power level is at least the predetermined power level.

11. The apparatus of claim 10, wherein the radar receiver is of a first bandwidth and the communication receiver is of a second bandwidth that is smaller than the first bandwidth.

12. The apparatus of claim 11, wherein the first bandwidth is approximately 17 Megahertz (MHz) or less and the second bandwidth is greater than 17 MHz.

13. The apparatus of claim 12, wherein the second bandwidth is approximately 675 MHz.

14. The apparatus of claim 10, wherein said communication receiver and said radar receiver are disposed in separate integrated circuits.

15. The apparatus of claim 10, wherein the communication receiver is a wireless local area network receiver.

16. The apparatus of claim 10, wherein the communication receiver is configured to tune to each of a plurality of channels and to provide a signal for each of the tuned-to plurality of channels, and the radar receiver is configured to detect the one or more channels on which the radar signal is received based at least in part on said provided signals from each of the tuned-to plurality of channels.

17. The apparatus of claim 16, wherein the communication receiver is further configured to determine a channel quality of each of the plurality of channels.

18. A method comprising:

receiving a radar signal;

determining, with a first processing chain of a radar receiver, that the radar signal has a power level of at least a predetermined power level; and

detecting, with the radar receiver in cooperation with a communication receiver having a second processing chain, which is at least partially parallel with the first processing chain, one or more channels on which the radar signal is received based at least in part on said determining that the power level is at least the predetermined power level.

19. The method of claim 18, wherein said detecting of the one or more channels on which the radar signal is received further comprises:

tuning, by the communication receiver, to each of a plurality of channels; and

providing, by the communication receiver to the radar receiver, a signal for each of the tuned-to plurality of channels.

20. The method of claim 19, further comprising:

determining a channel quality for each of the plurality of channels.