Communications Systems

• US 20090163215A1
• Filed: 12/15/2008
• Published: 06/25/2009
• Est. Priority Date: 12/21/2007
• Status: Abandoned Application

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Abedi, Saied
• Application Number:
  US12/335,515
• Publication Number:
  US 20090163215A1
• Time in Patent Office: Days
• US Class Current: 455/446
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 48/04 based on user or terminal location or mobility data, e.g. moving direction, speed

Abstract

A method of reducing interference in a first wireless communications system, the first wireless communications system being operable in use to take part in a spectrum assignment process involving at least a second wireless communications system, the method comprising defining an exclusion zone in proximity to the first wireless communications system, the exclusion zone indicating that any mobile communications apparatus located within the exclusion zone is not permitted to communicate with the second wireless communications system using a portion of spectrum which was pre-assigned to the first wireless communications system and which is currently re-assigned to the second wireless communications system as part of the spectrum assignment process; and dynamically varying the size of the exclusion zone in dependence on a level of interference inflicted on the first wireless communications system.

Claims

1. A method of reducing interference in a first wireless communications system, the first wireless communications system being operable in use to take part in a spectrum assignment process involving at least a second wireless communications system, the method comprising

defining an exclusion zone in proximity to the first wireless communications system, the exclusion zone indicating that any mobile communications apparatus located within the exclusion zone is not permitted to communicate with the second wireless communications system using a portion of spectrum which was pre-assigned to the first wireless communications system and which is currently re-assigned to the second wireless communications system as part of the spectrum assignment process;

and

dynamically varying the size of the exclusion zone in dependence on a level of interference inflicted on the first wireless communications system.

2. The method of claim 1 comprising transmitting from the first wireless communications system a beacon signal the strength of which indicates the size of the exclusion zone, and adjusting the strength of the beacon signal in order to vary the size of the exclusion zone.

3. The method of claim 1 comprising storing a predefined mapping table of the level of interference against the size of the exclusion zone, and using the mapping table to vary the size of the exclusion zone in dependence on the level of interference.

4. The method of claim 1 comprising triggering a long-term spectrum assignment when the size of the exclusion zone reaches a maximum exclusion expansion.

15. The method of claim 1 wherein varying the size of the exclusion zone comprises varying a local size of a part of the exclusion zone.

16. The method of claim 15 comprising transmitting from the first wireless communications system a local beacon signal the strength of which indicates the local size of the part of the exclusion zone, and adjusting the strength of the local beacon signal in order to vary the local size of the part of the exclusion zone.

21. A computer program which, when run on a computer, causes the computer to perform the method of claim 1.

5. A method of operating a controller for use with a first wireless communications system, the first wireless communications system being operable in use to take part in a spectrum assignment process involving at least a second wireless communications system, the first wireless communications system defining an exclusion zone in proximity to the first wireless communications system, the exclusion zone indicating that any mobile communications apparatus located within the exclusion zone is not permitted to communicate with the second wireless communications system using a portion of spectrum which was pre-assigned to the first wireless communications system and which is currently re-assigned to the second wireless communications system as part of the spectrum assignment process, the method comprising

receiving a signal which is indicative of a level of interference inflicted on the first wireless communications system;

determining, in dependence on the level of interference, a desired size of the exclusion zone;

transmitting to the first wireless communications system a signal which is indicative of the desired size of the exclusion zone.

6. The method of claim 5 comprising storing a predefined mapping table of the level of interference against the desired size of the exclusion zone, and using the mapping table to determine the desired size of the exclusion zone.

7. The method of claim 5 comprising triggering a long-term spectrum assignment when the desired size of the exclusion zone reaches a maximum exclusion expansion.

19. The method of claim 5 wherein determining a desired size of the exclusion zone comprises determining a desired local size of a part of the exclusion zone.

22. A computer program which, when run on a computer, causes the computer to perform the method of claim 5.

8. Apparatus for reducing interference in a first wireless communications system, the first wireless communications system being operable in use to take part in a spectrum assignment process involving at least a second wireless communications system, the apparatus comprising

exclusion zone circuitry configured to define an exclusion zone in proximity to the first wireless communications system, the exclusion zone indicating that any mobile communications apparatus located within the exclusion zone is not permitted to communicate with the second wireless communications system using a portion of spectrum which was pre-assigned to the first wireless communications system and which is currently re-assigned to the second wireless communications system as part of the spectrum assignment process;

wherein the exclusion zone circuitry is configured dynamically to vary the size of the exclusion zone in dependence on a level of interference inflicted on the first wireless communications system.

9. The apparatus of claim 8 comprising beacon circuitry configured to transmit a beacon signal the strength of which indicates the size of the exclusion zone, and wherein the exclusion zone circuitry is configured to adjust the strength of the beacon signal in order to vary the size of the exclusion zone.

10. The apparatus of claim 8 comprising memory circuitry configured to store a predefined mapping table of the level of interference against the size of the exclusion zone, wherein the exclusion zone circuitry is configured to use the mapping table to vary the size of the exclusion zone in dependence on the level of interference.

11. The apparatus of claim 8 comprising triggering circuitry configured to trigger a long-term spectrum assignment when the size of the exclusion zone reaches a maximum exclusion expansion.

17. The apparatus of claim 8 wherein the exclusion zone circuitry is configured to vary the size of the exclusion zone by varying a local size of a part of the exclusion zone.

18. The apparatus of claim 17 comprising beacon circuitry configured to transmit from the first wireless communications system a local beacon signal the strength of which indicates the local size of the part of the exclusion zone, and wherein the exclusion zone circuitry is configured to adjust the strength of the local beacon signal in order to vary the local size of the part of the exclusion zone.

12. A controller for use with a first wireless communications system, the first wireless communications system being operable in use to take part in a spectrum assignment process involving at least a second wireless communications system, the first wireless communications system defining an exclusion zone in proximity to the first wireless communications system, the exclusion zone indicating that any mobile communications apparatus located within the exclusion zone is not permitted to communicate with the second wireless communications system using a portion of spectrum which was pre-assigned to the first wireless communications system and which is currently re-assigned to the second wireless communications system as part of the spectrum assignment process, the controller comprising

communications circuitry configured to receive a signal which is indicative of a level of interference inflicted on the first wireless communications system;

control circuitry configured to determine, in dependence on the level of interference, a desired size of the exclusion zone;

wherein the communications circuitry is configured to transmit to the first wireless communications system a signal which is indicative of the desired size of the exclusion zone.

13. The controller of claim 12 comprising memory circuitry configured to store a predefined mapping table of the level of interference against the desired size of the exclusion zone, wherein the control circuitry is configured to use the mapping table to determine the desired size of the exclusion zone.

14. The controller of claim 12 wherein the control circuitry is configured to trigger a long-term spectrum assignment when the desired size of the exclusion zone reaches a maximum exclusion expansion.

20. The controller of claim 12 wherein the control circuitry is configured to determine a desired size of the exclusion zone by determining a desired local size of a part of the exclusion zone.