Method for addressing user location errors in a cognitive radio system

• US 8,213,954 B2
• Filed: 08/28/2007
• Issued: 07/03/2012
• Est. Priority Date: 08/28/2007
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola Solutions, Inc.
• Inventors: Gurney, David P., Chiou, Wayne W., Ekl, Randy L., Weisman, Douglas H.
• Primary Examiner(s): Hu, Jinsong
• Assistant Examiner(s): Shen, Qun
• Application Number:
  US11/845,940
• Publication Number:
  US 20090061779A1
• Time in Patent Office: 1,771 Days
• Field of Search: 455/456.1, 455/404.2, 455/67.11
• US Class Current: 455/456.1
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition

Abstract

A cognitive radio (CR) system (102) includes CR units (108, 110) that determine and update location-based system operating parameters to avoid interference with other systems operating in the same frequency band. Operational Location Uncertainty region and Allowed Location Error regions can be applied. The CR unit trades off between both, available channels and maximum system operating parameters, such that as Location Uncertainty of the CR device increases, available CR channels and location-based CR system operating parameters decrease over a maximum network reach.

Claims

1. A method of utilizing a geo-location database to avoid interference from a cognitive radio (CR) unit to at least one primary incumbent system, comprising:

estimating, at the CR unit, an Operational Location Uncertainty region for the CR unit, wherein the Operational Location Uncertainty Region comprises a plurality of location points, wherein estimating further comprises;

estimating an operating location for the CR unit;

estimating an operating location estimate accuracy for the estimated operating location;

providing an allowed location determination error for the CR unit by a regulatory authority; and

wherein an Allowed Location Error Region is determined as being centered on the operating location of the CR unit, and extends outward to a distance equal to the difference between the allowed location determination error and the operating location estimate accuracy;

deriving, from the geo-location database, a plurality of location-based system operating parameters that are capable of avoiding interference to the at least one primary incumbent system, wherein the geo-location database represents each of the plurality of location points in the Operational Location Uncertainty Region by a corresponding location-based system operating parameter;

examining the corresponding location-based system operating parameter at each of the plurality of location points in the Operational Location Uncertainty Region to determine a location-based system operating parameter from among the plurality of location points; and

operating the CR unit with the determined location-based system operating parameter that avoids interference to the at least one primary incumbent system, and further comprising;

determining an updated location-based system operating parameter by selecting a maximum location-based system operating parameter from among a plurality of location points over the Allowed Location Error Region, wherein a location point corresponding to a center of the Allowed Location Error Region is a location point corresponding to a minimum location-based system operating parameter selected from among the plurality of location points in the Operational Location Uncertainty Region; and

operating the CR unit using the updated location-based system operating parameter.

2. The method of claim 1, further comprising repeating the steps of estimating through operating the CR unit in response to a change in the Operational Location Uncertainty region for the CR unit.

3. The method of claim 1, wherein the determined location-based system operating parameter comprises at least one of:

an allowed transmit power, an allowed operating bandwidth, an allowed transmit time duration.

4. The method of claim 1, further comprising determining the location-based system operating parameter by selecting a maximum location-based system operating parameter from among a plurality of location points over the Allowed Location Error Region, wherein the geo-location database represents each of the plurality of location points over the Allowed Location Error Region by a corresponding location-based system operating parameter.

5. The method of claim 3, where the transmit power level is determined as a minimum of a plurality of transmit power levels from among the plurality of location points in the Operational Location Uncertainty Region.

6. The method of claim 1, wherein the geo-location database is stored with variable spatial resolution.

7. The method of claim 6, wherein the spatial resolution of the geo-location database decreases as distance from a central CR unit operating location increases.

8. The method of claim 1, wherein the Operational Location Uncertainty Region is determined by one of:

estimating a maximum network reach, determining an actual network reach, CR unit mobility and a predetermined operating region.

9. The method of claim 8, wherein the maximum network reach is estimated from at least one of:

an allowed transmit power level, antenna pattern data, a directional antenna gain.

10. The method of claim 1, further comprising adjusting the estimated Operational Location Uncertainty Region based on mobility of the CR unit over an area in which the CR unit is contained and traversing over a period of time.

31. The method of claim 1, further comprising:

determining that there are one or more communication devices operating in the Operational Location Uncertainty Region on a co-channel corresponding to a channel of the CR unit; and

examining the corresponding location-based system operating parameter at the plurality of location points in the Operational Location Uncertainty Region to determine the location-based system operating parameter from among the plurality of location points without examining the location-based system operating parameter at one or more location points corresponding to the one or more communicating devices.

32. The method of claim 1, further comprises:

operating the CR unit in a home television spectrum white spaces (TVWS) communication system, and wherein a location of the CR unit is derived from a home address linked to a cable set top box located in the home.

11. A cognitive radio (CR) communication network, comprising:

a CR base station located within a network Location Uncertainty Region, the CR base station having an estimated maximum network reach and further storing a geo-location database comprising CR system operating parameters;

a prospective subscriber CR device, the prospective subscriber CR device having an Allowed Location Error Region about its center; and

the prospective subscriber CR device increasing its Location Uncertainty about the network Location Uncertainty Region in exchange for a decrease in available channels from the CR base station and a decrease in transmit power from the CR base station;

wherein the CR base station accesses the geo-location database to derive CR system operating parameters that are capable of avoiding interference to at least one primary incumbent system and further wherein the CR base station examines the derived CR system operating parameters by applying a maximization technique for trading off the Location Error Region for maximum allowed system operating parameters and applying a minimization technique for trading off the Location Uncertainty Region for minimum allowed system operating parameters to utilize a least amount of transmit power for communicating with the prospective subscriber device while avoiding interference to the at least one primary incumbent system; and

,

the network Location Uncertainty Region and Allowed Location Error Region being updated in response to an update in the location of the subscriber CR device; and

the CR system operating parameters being updated in response to the update in the at Allowed Location Error Region or Location Uncertainty Region; and

the prospective subscriber CR device being operated with the updated location-based system operating parameters that avoid interference to the at least one primary incumbent system.

12. The cognitive radio of claim 11, wherein the CR system operating parameters include the transmit power.

13. A method of updating a cognitive radio (CR) location-based operating parameters for communicating within a CR communication network comprising:

determining, at the CR unit, an Allowed Location Error Region for the CR unit, wherein the Allowed Location Error Region comprises a plurality of location points;

determining, at the CR unit, an Operational Location Uncertainty Region of the CR unit, wherein the Operational Location Uncertainty Region comprises a plurality of location points;

deriving, from a geo-location database, a plurality of location-based system operating parameters that are capable of avoiding interference to at least one primary incumbent system, wherein the geo-location database represents each location point in the Allowed Location Error Region and the Operational Location Uncertainty Region by a corresponding location-based system operating parameter;

examining the corresponding location-based system operating parameter at each of the plurality of location points in the operational Location Uncertainty Region to determine a minimum location-based system operating parameter from among the plurality of location points, wherein a location point corresponding to a center of the Allowed Location Error Region is a location point corresponding to the minimum location-based system operating parameter;

examining the corresponding location-based system operating parameter at each of the plurality of location points in the Allowed Location Error Region to determine a maximum location-based system operating parameter from among the plurality of location points;

updating the CR location-based system operating parameters with the maximum location-based system operating parameter; and

operating the CR unit with the maximum location-based system operating parameter that avoids interference to the at least one primary incumbent system.

14. The method of claim 13, wherein the location-based system operating parameters comprise at least one of:

a maximum allowable transmit power, an allowable operational bandwidth, an allowable transmit time duration.

15. The method of claim 13 wherein the operational Location Uncertainty Region is determined based on one or more of:

a maximum network reach, a predetermined operating region, CR device mobility.

16. The method of claim 13, wherein the minimum location-based system operating parameter corresponds to a least amount of transmit power level and further wherein the least amount of transmit power level is determined as a minimum of a plurality of transmit power levels from among the plurality of location points in the Operational Location Uncertainty Region.

17. The method of claim 14, wherein the maximum location-based system operating parameter corresponds to the maximum allowable transmit power level and further wherein the maximum allowable transmit power level is determined as a maximum of a plurality of transmit levels from among the plurality of location points in the Allowed Location Error Region.

18. The method of claim 13, wherein the Allowed Location Error Region is determined by a current location of the CR unit, location estimate accuracy of the CR unit and an allowed location determination error for the CR unit.

19. A cognitive radio (CR) device, comprising:

a transmitter;

a controller coupled to the transmitter, the controller and transmitter maintaining a geo-location database comprising system operating parameters for the CR device; and

the CR device operating within an Operation Location Uncertainty region comprising a plurality of location points, and the CR device having an Allowed Location Error Region about its center, the CR device accessing the geo-location database to derive CR system operating parameters that are capable of avoiding interference to at least one primary incumbent system and further trading off between both available channels and maximum system operating parameters, such that as Location Uncertainty of the CR device increases, available CR channels and CR system operating parameters decrease, wherein the CR device is operated with the decrease in CR system operating parameters that avoid interference to the at least one primary incumbent system;

wherein the derived CR system operating parameters correspond to transmit power levels, and further wherein the maximum system operating parameters include a maximum allowable transmit power level that is determined as a maximum of a plurality of transmit power levels from among the plurality of location points in the Allowed Location Error Region, and further wherein the minimum allowed system operating parameters include a least amount of transmit power level that is determined as a minimum of a plurality of transmit power levels from among the plurality of location points in the Operation Location Uncertainty Region; and

the Location Uncertainty being updated based on updates to the location of the CR device, and the CR system operating parameters being updated in response to the update in the Location Uncertainty; and

the CR device being operated with the updated CR system operating parameters that avoid interference to the at least one primary incumbent system.

20. The method of claim 19, wherein each derived system operating parameter corresponds to a transmit power level and further wherein the CR device determines a least amount of transmit power level from among a plurality of transmit power levels for communication.

21. The CR device of claim 19, wherein the CR device comprises a mobile CR radio operating within a public safety network.

22. A method of communicating in a cognitive radio (CR) communication network having at least a mobile CR unit, comprising:

at the mobile CR unit;

estimating the location of the mobile CR unit;

determining at least one of an Allowed Location Error Region or Operational Location Uncertainty Region for the CR unit, wherein the Allowed Location Error Region or the Operational Location Uncertainty Region comprises a plurality of location points—

deriving, from a geo-location database, a plurality of location-based system operating parameters that is capable of avoiding interference to at least one primary incumbent system, wherein the geo-location database represents each location point in the Allowed Location Error Region or the Operational Location Uncertainty Region by a corresponding location-based system operating parameter, wherein each derived location-based system operating parameter corresponds to a transmit power level;

examining the corresponding location-based system operating parameter at each of the plurality of location points either in the Allowed Location Error Region or Operational Location Uncertainty Region to determine a location-based system operating parameter from among the plurality of location points, wherein the step of examining, comprises;

determining the Allowed Location Error Region for the CR unit and applying a maximization technique for trading off Location Error Region for maximum allowed system operating parameters, wherein the maximum allowed system operating parameters include a maximum allowable transmit power level that is determined as a maximum of a plurality of transmit power levels from among the plurality of location points in the Allowed Location Error Region; and

determining the Operational Location Uncertainty Region for the CR unit and applying a minimization technique for trading off a Location Uncertainty Region for minimum allowed system operating parameters, wherein the minimum allowed system operating parameters include a least amount of transmit power level that is determined as a minimum of a plurality of transmit power levels from among the plurality of location points in the Operation Location Uncertainty Region;

updating the at least one of Location Uncertainty Region and Location error Region based on an update in the location of the mobile CR unit; and

updating the location-based system operating parameter in response to the update in the at least one of the Allowed Location Error Region or Operational Location Uncertainty Region; and

operating the CR unit with the updated location-based system operating parameter that avoids interference to the at least one primary incumbent system.

23. The method of claim 22, wherein the location-based system operating parameter comprises a global CR transmit power limit utilized by the mobile CR unit within the Operational Location Uncertainty Region.

24. The method of claim 22, wherein the communication network comprises an in-home television spectrum white spaces (TVWS) communication system, and wherein the location of the CR unit is derived from a home address linked to a cable set top box located in the home.

25. The method of claim 22, wherein the location of the mobile CR unit is derived based on an input that includes one or more of street address, locale and city.

26. The method of claim 22, wherein the Location Uncertainty Region is determined by estimating maximum network reach.

27. The method of claim 26, wherein maximum network reach is based on propagation models and the current value of allowed transmit power.

28. The method of claim 22 wherein the location-based system operating parameter comprises one or more of:

CR base unit antenna pattern, directional antenna gain applied to refine the network reach estimate.

29. The method of claim 22, wherein the mobile CR unit operates within a Public Safety Network.

30. The method of claim 22, wherein the step of determining further comprises:

determining the Operational Location Uncertainty Region for the CR unit,

determining that there are co-channel transmitters operating within the Operational Location Uncertainty region; and

examining the corresponding location-based system operating parameter at each of the plurality of location points in the Operational Location Uncertainty Region to determine the location-based system operating parameter without examining the location-based system operating parameter at one or more location points corresponding to the co-channel transmitters.