Techniques for reducing noise and interference in wireless communication systems

• US 8,229,362 B2
• Filed: 05/18/2009
• Issued: 07/24/2012
• Est. Priority Date: 05/18/2009
• Status: Expired due to Fees

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola Mobility, Inc. (Lenovo Group Ltd.)
• Inventors: Hariharan, Raghunath, Stephens, Robert V.
• Primary Examiner(s): Donovan, Lincoln
• Assistant Examiner(s): Chen, Sibin
• Application Number:
  US12/467,473
• Publication Number:
  US 20100291876A1
• Time in Patent Office: 1,163 Days
• Field of Search: None
• US Class Current: 455/63.1
• CPC Class Codes: H04W 72/541 using the level of interference

Abstract

A technique for decreasing noise and interference in an uplink of a wireless communication system includes detecting, at a serving base station, noise and interference levels above a threshold. In response to the detecting, a noise and interference measurement frame is scheduled that includes respective allocated portions for respective active subscriber stations and respective unallocated portions that are adjacent to the respective allocated portions and are not allocated to one of the respective active subscriber stations. The respective allocated portions and the respective unallocated portions are configured in a selected pattern in the noise and interference measurement frame. The respective noise and interference levels are determined, at the serving base station, in the respective unallocated portions of the noise and interference measurement frame. One or more rogue subscriber stations, included in the respective active subscriber stations, are then identified based on the respective noise and interference levels associated with the respective active subscriber stations. When it is ambiguous as to whether a subscriber station is a rogue subscriber station, additional noise and interference measurement frames may be scheduled to resolve the ambiguity.

Claims

1. A method of decreasing noise and interference in an uplink of a wireless communication system, comprising:

detecting, at a serving base station, noise and interference levels above a threshold in unallocated portions for active subscriber stations, wherein the unallocated portions comprise the portions that are not assigned to any active subscriber station;

scheduling, in response to the detecting, a noise and interference measurement frame that includes respective allocated portions for respective active subscriber stations and respective unallocated portions that are adjacent to the respective allocated portions, wherein the respective allocated portions and the respective unallocated portions are configured in a selected pattern;

determining based on the scheduled frame, at the serving base station, respective signal levels in allocated portions and respective noise and interference levels in the respective unallocated portions of the noise and interference measurement frame;

identifying one or more rogue subscriber stations, included in the respective active subscriber stations, based on the respective noise and interference levels associated with the respective active subscriber stations; and

isolating the identified one or more rogue subscriber stations from other active subscriber stations.

2. The method of claim 1, wherein the respective active subscriber stations are each allocated respective single transmission time-slots in the noise and interference measurement frame, and wherein none of the respective single transmission time-slots are adjacent.

3. The method of claim 2, wherein the respective single transmission time-slots are separated in time by at least two unallocated time-slots in the noise and interference measurement frame.

4. The method of claim 1, further comprising:

placing the one or more rogue subscriber stations in a rogue device list; and

deregistering, with the serving base station, the one or more rogue subscriber stations.

5. The method of claim 4, further comprising:

adding respective medium access control addresses for the one or more rogue subscriber stations to a blacklist; and

filtering, at the serving base station, initial ranging requests from the one or more rogue subscriber stations on the blacklist.

6. The method of claim 4, further comprising:

reporting the one or more rogue subscriber stations in the rogue device list to an element management system.

7. The method of claim 1, wherein the detecting, at a serving base station, noise and interference levels above a threshold further comprises:

periodically determining noise and interference levels in unallocated portions of an uplink subframe; and

comparing the determined noise and interference levels to the threshold.

8. The method of claim 1, further comprising:

determining, at the serving base station, respective signal levels in the respective allocated portions of the noise and interference measurement frame; and

identifying the one or more rogue subscriber stations, included in the respective active subscriber stations, based on the respective noise and interference levels and the respective signal levels for the respective active subscriber stations.

9. A method of decreasing noise and interference in an uplink of a wireless communication system, comprising:

detecting, at a serving base station, noise and interference levels above a threshold in unallocated portions for active subscriber stations, wherein the unallocated portions comprise the portions that are not assigned to any active subscriber station;

scheduling, in response to the detecting, a first noise and interference measurement frame that includes respective allocated portions for respective active subscriber stations and respective unallocated portions that are adjacent to the respective allocated portions, wherein the respective allocated portions and the respective unallocated portions are configured in a selected pattern;

determining based on the scheduled frame, at the serving base station, respective noise and interference levels in the respective unallocated portions of the first noise and interference measurement frame;

determining based on the scheduled frame, at the serving base station, respective signal levels in the respective allocated portions of the first noise and interference measurement frame;

identifying one or more rogue subscriber stations, included in the respective active subscriber stations, based on the respective noise and interference levels and the respective signal levels for the respective active subscriber stations and

isolating the identified one or more rogue subscriber stations from other active subscriber stations.

10. The method of claim 9, wherein the respective active subscriber stations are each allocated respective single transmission time-slots in the first noise and interference measurement frame, and wherein none of the respective single transmission time-slots are adjacent.

11. The method of claim 10, wherein the respective single transmission time-slots are separated in time by at least two unallocated time-slots in the first noise and interference measurement frame.

12. The method of claim 9, further comprising:

placing the one or more rogue subscriber stations in a rogue device list; and

deregistering, with the serving base station, the one or more rogue subscriber stations.

13. The method of claim 12, further comprising:

adding respective medium access control addresses for the one or more rogue subscriber stations to a blacklist; and

filtering, at the serving base station, initial ranging requests from the one or more rogue subscriber stations on the blacklist.

14. The method of claim 13, further comprising:

reporting the one or more rogue subscriber stations in the rogue device list to an element management system.

15. The method of claim 9, further comprising

periodically determining noise and interference levels in unallocated portions of an uplink subframe;

and

comparing the determined noise and interference levels in the unallocated portions of the uplink subframe to a threshold to determine whether to schedule the first noise and interference measurement frame.

16. The method of claim 9, further comprising:

scheduling, when the determined respective noise and interference levels and the determined signal levels associated with the first noise and interference measurement frame are ambiguous as to whether two or more of the respective active subscriber stations should be included in the one or more rogue subscriber stations, a second noise and interference measurement frame that includes respective allocated portions for the two or more of the respective active subscriber stations and respective unallocated portions that are adjacent to the respective allocated portions and are not allocated to one of the two or more of the respective active subscriber stations.

17. A wireless communication device, comprising:

a scheduler configured to;

detect noise and interference levels above a threshold in unallocated portions for active subscriber stations, wherein the unallocated portions comprise the portions that are not assigned to any active subscriber station;

a transceiver configured to;

transmit, in response to the detection, a schedule for a first noise and interference measurement frame that includes respective allocated portions for respective active subscriber stations and respective unallocated portions that are adjacent to the respective allocated portions and are not allocated to one of the respective active subscriber stations, wherein the respective allocated portions and the respective unallocated portions are configured in a selected pattern;

a circuit coupled to the transceiver, wherein the circuit is configured to;

measure, based on the scheduled frame, the respective noise and interference levels in the respective unallocated portions of the first noise and interference measurement frame;

measure, based on the scheduled frame, respective signal levels in respective allocated portions of the first noise and interference measurement frame;

identify one or more rogue subscriber stations, included in the respective active subscriber stations, or determine that none of the respective active subscriber stations are rogue subscriber stations based on the respective noise and interference levels and the respective signal levels for the respective active subscriber stations; and

isolate the identified one or more rogue subscriber stations from other active subscriber stations.

18. The wireless communication device of claim 17, wherein the respective active subscriber stations are each allocated respective single transmission time-slots in the first noise and interference measurement frame, and wherein the respective single transmission time-slots are separated in time by at least two unallocated time-slots in the first noise and interference measurement frame.

19. The wireless communication device of claim 17, wherein the circuit is further configured to:

periodically measure noise and interference levels in an unallocated portion of an uplink subframe; and

compare the determined noise and interference levels in the unallocated portion of the uplink subframe to a threshold to determine whether to schedule the first noise and interference measurement frame.

20. The wireless communication device of claim 17, wherein the circuit is further configured to:

schedule, when the determined respective noise and interference levels and the determined signal levels associated with the first noise and interference measurement frame are ambiguous as to whether two or more of the respective active subscriber stations should be included in the one or more rogue subscriber stations, a second noise and interference measurement frame that includes respective allocated portions for the two or more of the respective active subscriber stations and respective unallocated portions that are adjacent to the respective allocated portions and are not allocated to one of the two or more of the respective active subscriber stations.