Method and system for reducing channel interference in a frame-synchronized wireless communication system

• US 7,877,061 B2
• Filed: 12/28/2006
• Issued: 01/25/2011
• Est. Priority Date: 11/15/2000
• Status: Expired due to Fees

• Current Assignee: Quarterhill Inc. (f/k/a Wi-LAN Inc.)
• Original Assignee: Quarterhill Inc. (f/k/a Wi-LAN Inc.)
• Inventors: Gilbert, Shelden L., Klein, Israel Jay, Stanwood, Kenneth L., Behar, Jacques
• Primary Examiner(s): Edouard; Patrick N
• Assistant Examiner(s): Genack; Matthew W
• Application Number:
  US11/617,557
• Publication Number:
  US 20070111665A1
• Time in Patent Office: 1,489 Days
• Field of Search: 455 631- 632, 455/67.11, 455/423, 455446-447, 455/449, 370/277, 370/281, 370/296, 370328-330, 370/337, 370/347, 370/436, 370/478
• US Class Current: 455/63.1
• CPC Class Codes: H04W 16/02 Resource partitioning among network components, e.g. reuse partitioning
• CPC Class Codes: H04W 16/12 Fixed resource partitioning
• CPC Class Codes: H04W 16/24 Cell structures

Abstract

A method reduces channel interference in a communication system that includes base stations and terminal stations with each base station having a plurality of sectors, each sector having a channel, and with each terminal station associated with a sector of a base station. A first set of terminal stations associated with a first sector that may potentially interfere with a second set of terminal stations associated with a second sector is determined. A first frequency sub-channel for use by the first set of terminal stations is selected and a second frequency sub-channel for use by the second set of terminal stations is selected. Transmissions by the first set of terminal stations are coordinated with transmissions by the second set of terminal stations, thereby reducing channel interference between the terminal stations of the first set and the terminal stations of the second set, as seen by a base station in the first or second sector.

Claims

1. A method for reducing channel interference in a communication system that includes base stations, with each base station having a plurality of sectors and each sector having a channel, and terminal stations with each terminal station associated with a base station sector, the method comprising:

determining a first set of terminal stations in a first base station sector that operate using a channel that potentially interferes with a second set of terminal stations in a second base station sector that operate on the same channel as the first base station sector, where the first set of terminal stations lie along a line of sight that passes through the second base station sector;

selecting a first sub-channel for use by the first set of terminal stations;

selecting a second sub-channel for use by the second set of terminal stations; and

coordinating uplink transmissions by the first set of terminal stations with uplink transmissions by the second set of terminal stations, the first set of terminal stations uplink using the first sub-channel and the second set of terminal stations uplink using the second sub-channel, thereby reducing channel interference at the second base station sector.

2. A method for reducing channel interference in a communication system that includes base stations and terminal stations with each base station having a plurality of sectors, each sector having a channel, and with each terminal station associated with a sector of a base station, the method comprising:

determining a first set of terminal stations associated with a first sector that may potentially interfere with a second set of terminal stations associated with a second sector;

selecting a first frequency sub-channel for use by the first set of terminal stations;

selecting a second frequency sub-channel for use by the second set of terminal stations; and

coordinating uplink transmissions by the first set of terminal stations with uplink transmissions by the second set of terminal stations, thereby reducing channel interference between the terminal stations of the first set and the terminal stations of the second set, as seen by a base station in the first or second sector.

15. A method as claimed in claim 2, wherein the first sector and the second sector operate using the same channel and the second sector is adjacent to the first sector.

3. A method for reducing channel interference in a communication system that includes base stations and terminal stations with each base station having sectors, each sector having a communication channel and each terminal station in a base station sector, the method comprising:

determining a first set of terminal stations in a first base station sector that may potentially interfere with a second set of terminal stations in a second base station sector;

defining a first frequency sub-channel within the communication channel of the first base station sector for use by the first set of terminal stations;

defining a second frequency sub-channel within the communication channel of the second base station sector for use by the second set of terminal stations; and

coordinating downlink transmissions to the first set of terminal stations with downlink transmissions to the second set of terminal stations, thereby reducing channel interference between the terminal stations of the first set and the terminal stations of the second set, as seen by one or more terminal stations of the first or second set of terminal stations.

16. A method as claimed in claim 3, wherein the first base station sector and the second base station sector operate using the same channel and are adjacent sectors.

4. A method for reducing channel interference in a communication system that includes terminal stations operating within at least two base station sectors with each sector having a communication channel, the method comprising:

identifying in a first sector a first set of terminal stations that may potentially interfere with a second set of terminal stations in a second sector;

separating a radio frequency channel into a first sub-channel and a second sub-channel;

establishing communications with the first set of terminal stations over the first sub-channel, and establishing communications with the second set of terminal stations over the second sub-channel wherein the frequency of the first sub-channel and the second sub-channel are orthogonal; and

coordinating communication to and from the first set of terminal stations and communications to and from the second set of terminals stations to minimize channel interference.

5. A method as claimed in claim 4, wherein the first and the second set of terminal stations are located in adjacent sectors served by the same base station.

6. A method as claimed in claim 4, wherein the first and the second set of terminal stations are located in adjacent sectors served by different base stations.

7. A method as claimed in claim 4, wherein the first and the second sub-channels are used for uplink communications.

8. A method as claimed in claim 4, wherein the first and the second sub-channels are used for downlink communications.

9. A method as claimed in claim 4, wherein the step of coordinating comprises, when the terminal stations of the first and the second set transmit simultaneously:

measuring a first value of a quality parameter of the transmissions from the terminal stations in the first set;

measuring a second value of the quality parameter for the transmissions from the terminal stations in the second set; and

dynamically adapting a traffic characteristic of the communications with the terminal stations in the first set and the terminal stations in the second set, based on the first and second values.

10. A method as claimed in claim 9, wherein the quality parameter is the signal to noise ratio.

11. A method as claimed in claim 9, wherein the quality parameter is power.

12. A method as claimed in claim 9, wherein the traffic characteristic is a modulation scheme.

13. A method as claimed in claim 12, wherein the step of dynamically adapting comprises:

maintaining the modulation scheme of the communications with a first terminal station in the first set if the first value indicates an acceptable level of interference between the first terminal station and the terminal stations in the second set; and

changing to a more robust modulation scheme for communications with the first terminal if the first value indicates an unacceptable level of interference between the first terminal station and the terminal stations in the second set.

14. A method as claimed in claim 12, wherein the step of dynamically adapting comprises using a less robust modulation scheme for communications with a first terminal station in the first set if the first value indicates a large interference between the first terminal station and the terminal stations in the second set.

17. A method as claimed in claim 5, wherein the first sector and the second sector operate using the same channel.

18. A method as claimed in claim 6, wherein the first sector and the second sector operate using the same channel.