Dynamic frequency selection and radar detection with a wireless LAN

• US 20040033789A1
• Filed: 08/19/2002
• Published: 02/19/2004
• Est. Priority Date: 08/19/2002
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Tsien, Chih C.
• Granted Patent: US 7,155,230 B2
• Time in Patent Office: Days
• US Class Current: 455/130
• 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 communication receiver, said communication receiver includes a down-converter and a receiver signal strength indicator unit; and

a radar receiver, said radar receiver includes a peak detector and a comparator, the comparator to compare a radar signal passed from said receiver front end through said peak detector to said comparator with a reference signal to detect a radar signal having a predetermined power level, 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 communication receiver having a bandwidth of approximately 5 GHz.

6. An apparatus as claimed in claim 1, further including a wideband receiver input stage to couple to said communication receiver and said radar receiver.

7. An apparatus as claimed in claim 1, further including a wideband receiver input stage to couple to said communication receiver and said radar receiver, said wideband receiver input stage having a bandwidth of approximately 675 MHz.

8. An apparatus as claimed in claim 1, said communication receiver having an 8.5 MHz bandwidth for direct conversion.

9. An apparatus as claimed in claim 1, said communication receiver having a 17 MHz bandwidth for double conversion.

10. An apparatus as claimed in claim 1, the predetermined power level of the radar signal being about −

52 dBm.

11. An apparatus as claimed in claim 1, said communication receiver and said radar receiver being disposed in a single integrated circuit.

12. An apparatus as claimed in claim 1, said communication receiver and said radar receiver being disposed in separate integrated circuits.

13. An apparatus as claimed in claim 1, said radar receiver further including a video detector, a pulse shaper, and 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

14. 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.

15. An apparatus as claimed in claim 14, said radar receiver includes a pulse delay unit to provide a delayed version of the radar signal from the peak detector to the comparator.

16. An apparatus as claimed in claim 14, 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.

17. An apparatus as claimed in claim 14, 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.

18. An apparatus as claimed in claim 14, 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,

19. A method, comprising:

detecting the presence of a radar signal by comparing a level of the radar signal to a reference level to determine when the radar signal has a power level greater than a predetermined power level;

determining the channel on the radar signal by sweeping the 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.

20. A method as claimed in claim 19, said switching including selecting a channel alternative to the determined channel of the radar signal by selecting a channel having a higher signal-to-noise ratio.

21. A method as claimed in claim 19, said detecting the presence of a radar signal when the radar signal has a power level greater than about −

52 dBm.

22. A method as claimed in claim 19, said detecting including detecting a peak of the radar signal prior to said comparing.

23. A method as claimed in claim 19, said detecting including delaying the radar signal by a predetermined delay prior to the comparing.

24. A method as claimed in claim 19, said detecting including delaying the radar signal by a predetermined delay prior to said comparing, the predetermined delay to match a delay of the communication receiver.

25. An apparatus, comprising:

a wireless local area network receiver to receive a communications signal;

a radar receiver to detect a radar signal; and

a channel selector to switch said wireless local area network receiver to a higher quality channel when said radar receiver detects a radar signal.

26. An apparatus as claimed in claim 25, further comprising a wideband receiver front end to provide a wideband signal to said wireless local area network receiver and to said radar receiver.

27. An apparatus as claimed in claim 25, further comprising a radar power detector to detect a power level of a radar signal when the power level is at least a predetermined value.

28. An apparatus as claimed in claim 25, further comprising a radar channel detector for detecting a channel of the radar signal.

29. An apparatus as claimed in claim 25, further comprising a radar power detector to detect a power level of a radar signal when the power level is at least a predetermined value, and a radar channel detector for detecting a channel of the radar signal.