System and method for detection of primary spectrum users

• US 20070060065A1
• Filed: 09/13/2005
• Published: 03/15/2007
• Est. Priority Date: 09/13/2005
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Meil, Christopher, Kruys, Johannes
• Granted Patent: US 7,548,750 B2
• Time in Patent Office: Days
• US Class Current: 455/67.110
• 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: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02

Abstract

An external primary spectrum user detector (ESUD) is used to take over the role of integral radar detectors, and relieve user devices of the constraints associated with Primary Spectrum User detection. The ESUD can establish a relationship with the user devices by means of a cryptographic signature. The ESUD installation includes assigning it a frequency band to scan for primary spectrum user signals and the type of signals to be detected. Once activated, the ESUD will scan its assigned frequencies and emit to types of messages, “All Clear” and “Primary Spectrum User detected.” User devices on the network listen for the ESUD messages. In the absence of messages from the ESUD, the user devices activate their internal primary spectrum user detectors until ESUD messages are received.

Claims

1. An apparatus for primary spectrum user detection, comprising:

a wireless receiver for receiving signals on a predetermined frequency;

spectrum detection logic for examining the signals received on the predetermined frequency to determine whether a primary spectrum user signal was received; and

a network interface for transmitting at least one message from the group consisting of “

clear” and

“

primary spectrum user detected”

to another device on the network responsive to the spectrum detection device determining whether a primary spectrum user signal was received.

2. An apparatus according to claim 1 wherein the wireless receiver is configured to scan a plurality of frequencies, the spectrum detection logic examines signals from each of the plurality of frequencies and the network interface sends at least one message from the group consisting of “

clear” and

“

primary spectrum user detected”

for each of the plurality of frequencies responsive to the spectrum detection logic examination of each of the plurality of frequencies to another device on the network.

3. An apparatus according to claim 1, wherein clear messages are sent at a first predetermined interval and primary spectrum user detected messages are sent at a second predetermined interval.

4. An apparatus according to claim 1, further comprising:

dynamic frequency selection logic coupled to the spectrum detection logic and the network interface, the dynamic frequency selection logic configured to select a frequency responsive to the spectrum detection logic determining whether a primary spectrum user has been detected; and

wherein the network interface is responsive to send a message indicative of the selected frequency.

5. An apparatus according to claim 1, wherein the spectrum detection logic is configurable to detect a certain type of primary spectrum user.

6. An apparatus according to claim 1, wherein the spectrum detection log is configured to detect radar signals.

7. A wireless device, comprising:

a wireless transceiver;

dynamic frequency selection logic coupled to the wireless transceiver for selecting an operating frequency for the wireless transceiver;

a network interface coupled to the dynamic frequency selection logic and responsive to receiving a signal from a remote primary spectrum user detector to forward the signal from the remote primary spectrum user detector to the dynamic frequency selection logic;

a timer coupled to the network interface for determining the elapsed time from the last signal received from the remote primary spectrum user detector; and

primary spectrum user detection logic coupled to the timer and the dynamic frequency selection logic responsive to the timer to activate after a predetermined time has elapsed;

wherein the dynamic frequency selection logic is responsive to the signal from the remote primary spectrum user detector for selecting the operating frequency for the wireless transceiver; and

wherein the dynamic frequency selection logic is responsive to the primary spectrum user for selecting the operating frequency after the predetermined time has elapsed.

8. A wireless device according to claim 7, wherein the signal from the remote primary spectrum user detector received by the network interface is one of the group consisting of a “

frequency clear” and

“

primary spectrum user detected”

.

9. A wireless device according to claim 8 wherein the timer activates the primary spectrum user detection logic when one of the group consisting of a frequency clear message has not been received within a first predetermined interval and a primary spectrum user detected message has not been within a second predetermined interval.

10. An apparatus for primary spectrum user detection, comprising:

means adapted for receiving signals on a predetermined frequency;

means adapted for examining the signals received on means adapted for receiving to determine whether a primary spectrum user signal was received; and

means adapted for transmitting at least one message from the group consisting of “

clear” and

“

primary spectrum user detected”

to another device on the network responsive to the spectrum detection device determining whether a primary spectrum user signal was received.

11. An apparatus according to claim 10 wherein the means adapted for receiving signals is configured to scan a plurality of frequencies, the means adapted for examining the signals examines signals from each of the plurality of frequencies and the means adapted for transmitting at least one message from the group consisting of “

clear” and

“

primary spectrum user detected”

for each of the plurality of frequencies responsive to the spectrum detection logic examination of each of the plurality of frequencies to another device on the network.

12. An apparatus according to claim 10, further comprising:

dynamic frequency selection means coupled to the means adapted for examining and the means adapted for transmitting, the dynamic frequency selection means configured to select a frequency responsive to the means adapted for examining determining whether a primary spectrum user has been detected; and

wherein the means adapted for transmitting is responsive to send a message indicative of the selected frequency.

13. A wireless device, comprising:

means adapted for sending and receiving wireless signals;

dynamic frequency selection means coupled to the means adapted for sending and receiving wireless signals for selecting an operating frequency for the means adapted for sending and receiving wireless signals;

means adapted for communicating on a network coupled to the dynamic frequency selection means and responsive to receiving a signal from a remote primary spectrum user detector to forward the signal from the remote primary spectrum user detector to the dynamic frequency selection means;

timing means for determining the elapsed time from the last signal received from the remote primary spectrum user detector coupled to the network interface; and

primary spectrum user detection means coupled to the timing means and the dynamic frequency selection means responsive to the timing means to activate after a predetermined time has elapsed;

wherein the dynamic frequency selection means is responsive to the signal from the remote primary spectrum user detector for selecting the operating frequency for the wireless transceiver; and

wherein the dynamic frequency selection means is responsive to the primary spectrum user for selecting the operating frequency after the predetermined time has elapsed.

14. A wireless device according to claim 13, wherein the signal from the remote primary spectrum user detector received by the means adapted for communicating on a network is one of the group consisting of “

frequency clear” and

“

primary spectrum user detected”

.

15. A wireless device according to claim 14, wherein the timing means activates the primary spectrum user detection means when one of the group consisting of a “

frequency clear”

message has not been received within a first predetermined interval and a “

primary spectrum user detected”

message has not been within a second predetermined interval.

16. A method, comprising:

monitoring a channel;

determining whether a primary spectrum user is using the channel; and

sending a message indicative of whether primary spectrum user is using the channel within a predetermined time period.

17. A method according to claim 16, further comprising:

waiting a first predetermined time period before sending the message after a primary user has been detected; and

waiting a second predetermined time period before sending the message after no primary user has been detected.

18. A method according to claim 16, further comprising:

the monitoring step further comprising monitoring a plurality of channels;

the determining step further comprising determining whether a primary spectrum user is using at least one of the plurality of channels; and

the sending a message further comprises sending a message indicative whether the determining step determined a primary user is using at least one of the plurality of channels.

19. A method, comprising:

waiting for a message from a remote primary spectrum user detector indicative of whether a primary spectrum user has been detected on a channel;

selecting a channel responsive to receiving a message from the remote primary spectrum;

determining an elapsed time after the message has been received from the remote primary spectrum user detector; and

activating a second primary spectrum user detector responsive to the determining step determining the elapsed time exceeded a predetermined time.

20. A method according to claim 19, further comprising:

deactivating the second primary spectrum user detector upon receipt of a new message from the remote primary spectrum user detector.