Communications Systems

• US 20090163237A1
• Filed: 12/16/2008
• Published: 06/25/2009
• Est. Priority Date: 12/21/2007
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: ABEDI, Saied
• Granted Patent: US 8,694,035 B2
• Time in Patent Office: Days
• US Class Current: 455/501
• 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 varying the local size of a part only 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

varying the local size of a part only 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 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.

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

4. The method of claim 1 wherein varying the local size of the part of the exclusion zone comprises varying the size of the exclusion zone non-uniformly around the perimeter of the exclusion zone.

5. The method of claim 1 wherein varying the local size of the part of the exclusion zone comprises moving one or more portions of the perimeter of the exclusion zone towards or away from a central region of the exclusion zone.

6. The method of claim 5 comprising moving the said one or more portions independently of other portions of the perimeter.

7. The method of claim 1 wherein varying the local size of the part of the exclusion zone comprises dynamically varying the local size.

8. 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 local size of a part of the exclusion zone;

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

9. The method of claim 8 comprising storing a predefined mapping table of the level of interference against the desired local size of the part of the exclusion zone, and using the mapping table to determine the desired local size of the part of the exclusion zone.

10. The method of claim 8 wherein determining a desired local size of the part of the exclusion zone comprises determining a desired variation in the size of the exclusion zone which is non-uniform around the perimeter of the exclusion zone.

11. The method of claim 8 wherein determining a desired local size of the part of the exclusion zone comprises determining a desired movement of one or more portions of the perimeter of the exclusion zone towards or away from a central region of the exclusion zone.

12. The method of claim 11 comprising determining the desired movement of the said one or more portions independently of other portions of the perimeter.

13. 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 to vary the local size of a part of the exclusion zone in dependence on a level of interference inflicted on the first wireless communications system.

14. The apparatus of claim 13 comprising beacon circuitry configured to transmit 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.

15. The apparatus of claim 13 comprising memory circuitry configured to store a predefined mapping table of the level of interference against the local size of the part of the exclusion zone, wherein the exclusion zone circuitry is configured to use the mapping table to vary the local size of the part of the exclusion zone in dependence on the level of interference.

16. The apparatus of claim 13 wherein the exclusion zone circuitry is configured to vary the size of the exclusion zone non-uniformly around the perimeter of the exclusion zone.

17. The apparatus of claim 13 wherein the exclusion zone circuitry is configured to move one or more portions of the perimeter of the exclusion zone towards or away from a central region of the exclusion zone.

18. The apparatus of claim 17 wherein the exclusion zone circuitry is configured to move the said one or more portions independently of other portions of the perimeter.

19. The apparatus of claim 13 wherein the exclusion zone circuitry is configured to vary the local size dynamically.

20. 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 local size of a part 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 local size of the part of the exclusion zone.

21. The controller of claim 20 comprising memory circuitry configured to store a predefined mapping table of the level of interference against the desired local size of the part of the exclusion zone, wherein the control circuitry is configured to use the mapping table to determine the desired local size of the part of the exclusion zone.

22. The controller of claim 20 wherein the control circuitry is configured to determine a desired variation in the size of the exclusion zone which is non-uniform around the perimeter of the exclusion zone.