Wireless communication system with base station beam sweeping

• US 20030195017A1
• Filed: 06/03/2003
• Published: 10/16/2003
• Est. Priority Date: 09/30/1999
• Status: Active Grant

• Current Assignee: Fuyun Ling, Jack Holtzman, Stein A. Lundby, Tao Chen, Yu-Cheun Jou
• Original Assignee: Fuyun Ling, Jack Holtzman, Stein A. Lundby, Tao Chen, Yu-Cheun Jou
• Inventors: Jou, Yu-Cheun, Lundby, Stein A., Chen, Tao, Ling, Fuyun, Holtzman, Jack
• Granted Patent: US 7,117,017 B2
• Time in Patent Office: Days
• US Class Current: 455/562.1
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity
• CPC Class Codes: H04B 7/0615 of weighted versions of same signal
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming

Abstract

A method and apparatus for wireless communications wherein a base station transmits a signal to sending data to a subscriber station through a signal beam that sweeps through the coverage area of the base station. User data addressed to the subscriber station is buffered until the signal beam angle of the signal beam allows efficient transmission. The base station may alter the beam sweep speed or the shape of the beam'"'"'s radiation pattern over time to maximize system efficiency and capacity.

Claims

1. A method of identifying a time for transmitting user data on a forward link from a base station to a subscriber station, wherein the base station transmits and receives signals through a base station signal beam having a beam angle that changes over time, the method comprising:

storing the user data in a transmit buffer;

predicting an optimal transmit time for efficiently transmitting forward-link supplemental channel traffic to the subscriber station based on the beam angle; and

transmitting the user data at the predicted optimal transmit time.

2. The method of claim 1 wherein the predicting comprises comparing a reverse link transmit power to a reverse link power threshold.

3. The method of claim 2 wherein the predicting comprises evaluating a rate at which the user data is being accumulated in the transmit buffer.

4. The method of claim 1 wherein the predicting comprises correlating a transmit power transmitted by the subscriber station to the beam angle.

5. The method of claim 1 wherein the predicting comprises evaluating a rate at which the user data is being accumulated in the transmit buffer.

6. The method of claim 1 wherein the predicting comprises determining a value of the beam angle at which a target carrier-to-interference ratio can be maintained using minimal transmit power.

7. The method of claim 1 wherein the storing comprises storing the user data in a transmit buffer located in the base station.

8. The method of claim 1 wherein the storing comprises storing the user data in a transmit buffer located in a base station controller.

9. The method of claim 1 further comprising adjusting a rate of change of the beam angle based on the predicting.

10. The method of claim 1 further comprising forming the base station signal beam using at least one mechanically moving directional antenna.

11. The method of claim 1 further comprising forming the base station signal beam using a plurality of spatially separated antennas.

12. An apparatus comprising:

a buffer configured to store user data and to provide the user data to a channel element module based on a data release signal; and

a control processor configured to predict an optimal transmit time for efficiently transmitting forward-link traffic from a base station to a subscriber station, wherein the base station transmits and receives signals through a base station signal beam having a beam angle that changes over time, wherein the control processor is configured to predict the optimal transmit time based on the beam angle.

13. The apparatus of claim 12 further comprising a backhaul interface configured to transport the user data between the base station and a base station controller.

14. The apparatus of claim 12 further comprising a base station controller, wherein the base station controller comprises the buffer.

15. The apparatus of claim 12 further comprising the base station, wherein the base station comprises the buffer.

16. The apparatus of claim 12 further comprising a beam sweeping controller configured to form the base station signal beam using a plurality of spatially separated antennas.

17. The apparatus of claim 12 further comprising at least one mechanically moving directional antenna configured to form the base station signal beam.

18. The method of claim 12 further comprising a plurality of spatially separated antennas configured to form the base station signal beam.

19. A method of identifying a time for transmitting user data on a reverse link from a subscriber station to a base station, wherein the base station sends and receives signals through a base station beam having a beam angle that changes over time, the method comprising:

storing the user data in a transmit buffer;

determining an efficiency of sending the user data immediately on the reverse link; and

identifying the time to transmit the user data based on the efficiency.

20. The method of claim 19 further comprising transmitting the user data when a reverse link transmit power is below a reverse link power threshold.

21. The method of claim 19 wherein the determining comprises evaluating a rate at which the user data is being accumulated in the transmit buffer.

22. An apparatus comprising:

a transmit data buffer configured to store user data and to provide the user data to a channel element module based on a data release signal; and

a control processor configured to predict an optimal transmit time for efficiently transmitting reverse-link traffic from a subscriber station to a base station, wherein the base station transmits and receives signals through a base station signal beam having a beam angle that changes over time, wherein the control processor is configured to predict the optimal transmit time based on the beam angle.

23. The apparatus of claim 22 further comprising a power control module configured to monitor a signal-to-noise ratio of forward-link signals received from the base station, wherein the control processor is configured the predict the optimal transmit time based on the signal-to-noise ratio.

24. The apparatus of claim 22 further comprising a power control module configured to regulate a reverse-link power level of the transmitted reverse-link traffic, wherein the control processor is configured the predict the optimal transmit time based on the reverse-link power level.