Fixed wireless communication system having power control for downlink data traffic

• US 6,711,416 B1
• Filed: 11/28/2000
• Issued: 03/23/2004
• Est. Priority Date: 11/28/2000
• Status: Expired due to Fees

• Current Assignee: Clearwire Ip Holdings LLC (Deutsche Telekom AG)
• Original Assignee: Clearwire Corporation (Deutsche Telekom AG)
• Inventors: Zhang, Hongliang
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): Miller, Brandon J
• Application Number:
  US09/723,647
• Time in Patent Office: 1,211 Days
• Field of Search: 455/63, 455/67.1, 455/522, 455/524, 455/448, 455/449-450, 455/63.1, 455/67.11, 455/127.1
• US Class Current: 455/522
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 52/242 taking into account path loss
• CPC Class Codes: H04W 72/535 based on resource usage policies
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems

Abstract

A fixed wireless communication system adjusts the downlink data transmission power based on the location of a recipient remote subscriber unit to minimize co-channel interference. The network includes a plurality of service areas, each served by a base station that transmits data to the remote subscriber units within the service area. Each remote subscriber unit is assigned to a particular group to which a respective transmission power is associated.

Claims

1. A method for controlling a signal transmission power level from a base station to remote subscriber units in a fixed wireless communication system, the method comprising:

determining a pathloss range for a service area;

apportioning the pathloss range into a plurality of intervals;

assigning each of a plurality of groups to a respective one of the plurality of pathloss intervals;

assigning each one of a plurality of remote subscriber units to a respective one of the plurality of groups based upon a pathloss from a base station to the remote subscriber units;

assigning a signal transmit power level to each of the plurality of groups; and

adjusting a transmit power level of a signal transmitted by the base station to a destination remote subscriber unit based upon a power level associated with the group to which the destination remote subscriber unit is assigned.

2. The method according to claim 1, wherein determining the pathloss range for the service area further includes determining a difference between a maximum pathloss for the service area and a minimum pathloss for the service area.

3. The method according to claim 2, wherein apportioning the pathloss range into a plurality of groups further includes dividing the pathloss range by a predetermined group pathloss range interval.

4. The method according to claim 1, wherein apportioning the pathloss range into a plurality of groups further includes selecting a desired number of groups each having a corresponding pathloss range interval.

5. The method according to claim 1, wherein apportioning the pathloss range into pathloss intervals further includes linearly apportioning the pathloss range.

6. The method according to claim 1, further including receiving data to be transmitted by the base station and placing the received data in respective bins corresponding to the destination remote subscriber unit.

7. The method according to claim 6, further including assigning a respective transmit power level to the bins.

8. The method according to claim 1, further including re-assigning a remote subscribe unit to a respective group based upon a number of errors in data received by the destination remote subscriber unit.

9. The method according to claim 1, further including determining scaling factors for symbol constellation points in an OFDM system.

10. The method according to claim 9, wherein the scaling factors are derived from the signal transmit power associated with the groups.

11. A method for reducing co-channel interference in a fixed wireless communication system, comprising:

determining a respective area pathloss range for a plurality of service areas;

apportioning the area pathloss range for each service area into a plurality of pathloss intervals;

assigning each of a plurality of groups to a respective one of the plurality of pathloss intervals;

assigning each of a plurality of fixed remote subscriber units within a respective service area to one of the groups based upon a pathloss range from a base station to the remote subscriber unit;

assigning a respective transmit power level to each group based upon the group pathloss range; and

selecting a transmit power level for data to be transmitted to a destination remote subscriber unit based upon the group to which the destination remote subscriber unit is assigned.

12. The method according to claim 11, wherein the pathloss range corresponds to a difference between a maximum pathloss for the service area and a minimum pathloss for the service area.

13. The method according to claim 11, wherein the group pathloss range corresponds to the pathloss range for the service area divided by a selected group interval size.

14. The method according to claim 11, further including adaptively re-assigning a respective one of the remote subscriber units.

15. The method according to claim 11, further including assigning a respective constellation scaling level to each of the transmit power levels.

16. A fixed wireless communication system, comprising:

a base station for communicating with a plurality of remote subscriber units located within a service area having a predetermined pathloss range apportioned into a plurality of pathloss intervals;

a plurality of groups assigned to respective ones of the plurality of pathloss intervals and respective ones of the plurality of remote subscriber units being assigned to respective ones of the plurality of groups based upon a pathloss from the base station to each of the plurality of remote subscriber units;

a signal transmit power level being assigned to each of the plurality of groups, wherein the base station transmits data to a destination remote subscriber unit of the plurality of remote subscriber units at a power level assigned to a predetermined group of the plurality of groups to which the destination remote subscriber unit of the plurality of remote subscriber units is assigned.

17. The system according to claim 16, wherein the base station includes a data traffic scheduling entity for receiving data to be transmitted to the remote subscriber units, the data traffic scheduling entity including a plurality of bins each corresponding to a respective remote subscriber unit.

18. The system according to claim 17, wherein the data traffic scheduling entity further includes a lookup table for associating a respective transmit power level with data to be transmitted to the remote subscriber units.

19. The system according to claim 16, wherein the system is an OFDM system.

20. The system according to claim 16, wherein constellation symbols are scaled by respective scaling factors.

21. A method for controlling a signal transmission power level from a fixed base station to a plurality of fixed remote subscriber units in a wireless communication system, the method comprising:

determining a pathloss range for a service area serviced by the fixed base station and the plurality of fixed remote subscriber units;

measuring pathloss from the fixed base station to each one of the plurality of fixed remote subscriber units;

apportioning the pathloss range for the service area into a plurality of pathloss intervals;

assigning each of a plurality of group designations to a respective one of the plurality of pathloss intervals;

assigning each one of the plurality of fixed remote subscriber units to a respective one of the plurality of group designations based upon the measured pathloss from the fixed base station to such one of the plurality of fixed remote subscriber units;

assigning a signal transmit power level to each of the plurality of group designations;

adjusting a transmit power level of a signal transmitted by the fixed base station to one of the fixed remote subscriber units based upon a power level associated with the group to which the one of the fixed remote subscriber unit is assigned; and

assigning a constellation scaling level to each respective signal transmit power level corresponding to each of the plurality of groups for adjusting each respective signal transmit power level during a downlink data transmission.