SYSTEMS AND METHODS FOR A COGNITIVE RADIO HAVING ADAPTABLE CHARACTERISTICS

• US 20090268619A1
• Filed: 08/15/2007
• Published: 10/29/2009
• Est. Priority Date: 08/15/2007
• Status: Active Grant

• Current Assignee: Shared Spectrum Company
• Original Assignee: Shared Spectrum Company
• Inventors: DAIN, Dmitry, Livsics, Jevgenijs, McHenry, Mark A., Bazarov, Igor
• Granted Patent: US 8,184,653 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/54 based on quality criteria
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

Systems and methods for configuring a network of radios for dynamic spectrum access are described. A network radio can include hardware and/or software modules for detecting a radio environment and negotiating common communications channels with a plurality of other radios in the network. Network radio behavior can be defined by a plurality of predefined policies which are used in combination with the information about the radio environment to select common operating parameters.

Claims

1. A radio apparatus for communicating at a dynamically selected radio frequency, comprising:

a policy manager for storing at least one communications policy parameter;

a detector for detecting an environmental radio frequency condition; and

a spectrum manager in communication with the policy manager and the detector and configured to select a communication frequency based on the detected radio frequency condition and the at least one policy parameter.

2. The radio apparatus of claim 1, further comprising a rendezvous subsystem configured to coordinate communication at the dynamically-selected radio frequency with at least one cooperative node.

3. The radio apparatus of claim 2, the rendezvous subsystem further configured to operate in a plurality of modes, the modes comprising:

a startup mode in which an initial communication frequency is selected from a set of candidate frequencies provided by the spectrum manager.

4. The radio apparatus of claim 3, the rendezvous subsystem further configured to operate in the channel-switching mode when a non-cooperative node is detected on a communication channel in use by the radio apparatus.

5. The radio apparatus of claim 3, the modes further comprising:

a channel-switching mode in which a new communication frequency is selected based at least in part on the availability of the new communication frequency to at least one other cooperative node.

6. The radio apparatus of claim 3, the modes further comprising:

a channel maintenance mode in which communication is maintained with the at least one cooperative node.

7. The radio apparatus of claim 1, the spectrum manager configured to select a communication frequency based at least in part on the presence of a non-cooperative communication detected by the detector.

8. The radio apparatus of claim 1, the spectrum manager configured to select a communication frequency by characterizing allowable channels based on radio frequency data received from the detector.

9. The radio apparatus of claim 1, wherein the at least one policy parameter specifies a maximum frequency at which the detector can scan a spectrum.

10. The radio apparatus of claim 1, wherein the at least one policy parameter specifies at least one channel allowed for use by the radio apparatus.

11. A method of communicating on a dynamically-selected communication channel, the method comprising:

determining the availability of at least one channel considered available for use based on a use of the channel by a cooperative node, a use of the channel by a non-cooperative node, an absence of a signal in the channel, or a combination thereof;

selecting an initial communication channel from a candidate channel list, the candidate channel list identifying the at least one channel considered available; and

transmitting a packet to at least one cooperative node over the initial communication channel.

12. The method of claim 11, wherein the packet identifies a preferred channel on which the at least one cooperative node can transmit.

13. The method of claim 11, wherein the packet identifies a number of cooperative nodes using the initial channel.

14. The method of claim 11, wherein the packet indicates a number of channels identified as available for use.

15. The method of claim 11, wherein the packet indicates a geographical location of a cooperative node sending the packet.

16. The method of claim 15, wherein the cooperative node sending the packet is a base station.

17. The method of claim 11, further comprising:

in response to a detection of an adverse environmental frequency condition, selecting a new communication channel from the candidate channel list; and

notifying the at least one cooperative node of the new communication channel.

18. The method of claim 17, wherein the adverse environmental frequency condition comprises the use of the initial communication frequency by a non-cooperative node.

19. The method of claim 17, further comprising receiving a notification of the adverse environmental frequency condition from a remote cooperative node.

20. A method of communicating on a dynamically-selected communication channel, the method comprising:

identifying an initial communication channel used by a first cooperative node;

transmitting a synchronize packet to the first cooperative node over the initial communication channel, the synchronize packet including channel usage information detected by a second cooperative node; and

receiving an acknowledgement packet from the first cooperative node.

21. The method of claim 20, wherein the acknowledgement packet contains an indication of a preferred communication channel for the second cooperative node.

22. The method of claim 20, wherein identifying the initial communication channel comprises:

receiving spectrum usage information from a detector system;

characterizing communication channels based on the spectrum usage information;

identifying a communication channel as a cooperative control channel based on the characterization of the channel; and

receiving, from a cooperative node on the cooperative control channel, information identifying the initial communication channel.

23. The method of claim 20, wherein identifying the initial communication channel comprises reading a configuration file.

24. The method of claim 20, further comprising receiving a keep-alive packet from the first cooperative node.

25. The method of claim 24, wherein the keep-alive packet identifies a number of cooperative nodes using the initial channel.

26. The method of claim 24, wherein the keep-alive packet indicates a number of channels identified by the first cooperative node as available for use.

27. The method of claim 24, wherein the keep-alive packet indicates a geographical location of a the first cooperative node.

28. The method of claim 24, wherein the first cooperative node comprises a base station.

29. The method of claim 20, further comprising:

detecting an adverse environmental frequency condition; and

notifying the first cooperative node of the adverse environmental frequency condition.

30. The method of claim 29, wherein the adverse environmental frequency condition comprises the use of the initial communication frequency by a non-cooperative node.

31. The method of claim 20, further comprising sending a keep-alive packet to the first cooperative node, the keep-alive packet including channel information as detected by the second cooperative node.

32. A method of dynamically changing a communication channel, the method comprising:

during an active communication link with at least one cooperative node over an initial channel, detecting an environmental frequency condition on the initial channel;

transmitting an advertise request to the at least one cooperative node;

receiving at least one advertise reply during a predetermined time frame, the at least one advertising reply providing information from an associated cooperative node regarding channel availability as determined by the associated cooperative node;

identifying an available channel as a new communication channel;

transmitting a channel-switch request to the at least one cooperative node, the request identifying the new communication channel; and

communicating with the at least one cooperative node on the new channel.

33. The method of claim 32, wherein identifying the new communication channel comprises identifying a channel available to the at least one cooperative node based on the channel availability received from the at least one cooperative node.

34. The method of claim 32, further comprising:

after transmitting the channel-switch request, waiting a predetermined amount of time before communicating on the new channel.

35. The method of claim 32, wherein the environmental frequency condition comprises a lost neighbor.

36. The method of claim 32, wherein the environmental frequency condition comprises an empty channel.

37. The method of claim 32, wherein the environmental frequency condition comprises a non-cooperative node detected on the initial channel.

38. The method of claim 32, wherein the environmental frequency condition is detected by the at least one cooperative node.

39. A method of dynamically changing a communication channel, the method comprising:

during communication with a first cooperative node over an initial channel, detecting an environmental frequency condition on the initial channel;

responsive to detecting the environmental frequency condition, transmitting a reset request to the first cooperative node;

receiving an advertise request from the first cooperative node;

sending an advertise reply to the first cooperative node, the advertise reply providing information regarding channel availability as determined by a second cooperative node;

receiving a channel-switch request from the first cooperative node, the request identifying the new communication channel; and

communicating with the first cooperative node on the new channel.

40. The method of claim 39, wherein the environmental frequency condition comprises a lost neighbor.

41. The method of claim 39, wherein the environmental frequency condition comprises an empty channel.

42. The method of claim 39, wherein the environmental frequency condition comprises a non-cooperative node detected on the initial channel.

43. A method of identifying usable communication channels comprising:

receiving output from a radio frequency detector, the output providing usage information for a plurality of communication channels;

categorizing each of the plurality of communication channels according to the presence of a signal corresponding to use of the channel by a non-cooperative transmitter, the presence of a signal corresponding to use of the channel by a cooperative transmitter, the absence of a signal, or a combination thereof; and

generating a list of candidate channels, the list including each channel not having a signal indicating use of the channel by a non-cooperative transmitter.

44. The method of claim 43, further comprising providing the list of candidate channels to a rendezvous module configured to coordinate communication with at least one cooperative node.

45. The method of claim 43, wherein the categorizing comprises:

dividing a logical channel into a plurality of bins and characterizing each channel based on the radio frequency energy measured in each bin; and

measuring the time since a signal was detected on the channel.

46. A method of determining availability of a plurality of communication channels for use by a dynamic spectrum allocation system, the method comprising:

for each of the plurality of communication channels, dividing the channel into a plurality of bins;

measuring the power level of radio-frequency energy in each bin;

for each channel having at least a predetermined portion of bins with a detected power greater than a first predetermined threshold, identifying the channel as containing a cooperative signal; and

for each channel not identified as containing a cooperative signal but having at least one bin with a detected power greater than the first threshold, identifying the channel as containing a non-cooperative channel.

47. The method of claim 46, further comprising:

for each channel not identified as containing a cooperative signal and having at least a predetermined portion of bins with a detected power less than the first predetermined threshold and greater than a second predetermined threshold, identifying the channel as containing a cooperative signal.

48. The method of claim 46, further comprising:

updating a list of candidate channels to identify those channels containing a non-cooperative channel as not available for use by the dynamic spectrum allocation system.