CDMA signal power control using quadrature signal calculations

• US 6,370,109 B1
• Filed: 03/10/1999
• Issued: 04/09/2002
• Est. Priority Date: 03/10/1999
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Knight, Robin D., Soong, Anthony C. K., Harms, Brian K., Pressley, Todd A., Schwartz, Bruce S.
• Primary Examiner(s): HSU, ALPUS
• Application Number:
  US09/265,205
• Time in Patent Office: 1,126 Days
• Field of Search: 370/203, 370/206, 370/207, 370/208, 370/320, 370/328, 370/329, 370/335, 370/342, 375/130, 375/140, 375/141, 375/146, 375/295-297, 375/302-304, 375/344-346, 375/350, 375/367, 455/68, 455/69, 455/70, 455/115, 455/116, 455/117, 455/230, 455/232.1, 455/234.1, 455/234.2, 455/422, 455/450, 455/507, 455/517, 455/522
• US Class Current: 370/203
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

The invention is CDMA quadrature signal technology that controls the transmit power of a CDMA signal. The CDMA quadrature signal technology receives a CDMA signal, and in response, process quadrature components of the CDMA signal to generate a power control signal. The CDMA quadrature signal technology adjusts the gain of the CDMA signal in response to the power control signal. A CDMA transmitter transmits the CDMA signal after the gain is adjusted. One example of the CDMA transmitter is a CDMA base station. Using the invention, a multi-sector CDMA base station can control power without transferring gain information to base station components for all sectors. The invention eliminates unnecessary data transfer and storage.

Claims

1. A method for transmitting a Code Division Multiple Access (CDMA) signal, the method comprising receiving the CDMA signal;

in response to receiving the CDMA signal, processing quadrature components of the CDMA signal to generate a power control signal;

adjusting gain of the CDMA signal in response to the power control signal; and

transmitting the CDMA signal after adjusting the gain;

wherein processing the quadrature components of the CDMA signal to generate the power control signal further comprises;

processing the quadrature components of the CDMA signal to determine a quadrature CDMA signal power value;

monitoring transmit power of the CDMA signal;

comparing the quadrature CDMA signal power value to the transmit power; and

generating the power control signal based on the comparison.

2. The method of claim 1 wherein processing the quadrature components of the CDMA signal to determine a quadrature CDMA signal power value further comprises:

squaring a quadrature I component of the CDMA signal;

squaring a quadrature Q component of the CDMA signal; and

summing the squared quadrature I component of the CDMA signal and the squared quadrature Q component of the CDMA signal.

3. The method of claim 1 wherein comparing the quadrature CDMA signal power value to the transmit power and generating the power control signal based on the comparison further comprises:

determining a ratio of the transmit power to the quadrature CDMA signal power value;

comparing the ratio to a pre-determined value; and

generating the power control signal to adjust the gain to change the ratio to be closer to the pre-determined value.

4. The method of claim 1 further comprising generating the CDMA signal.

5. The method of claim 1 wherein the method is performed by a multi-sector CDMA base station.

6. The method of claim 1 wherein adjusting gain of the CDMA signal comprises adjusting gain of the CDMA signal without transferring per call gains to gain control circuitry.

7. The method of claim 1 further comprising, in response to receiving the CDMA signal, processing the quadrature components of the CDMA signal to generate a capacity control signal.

8. The method of claim 7 wherein the capacity control signal indicates excess forward link capacity.

9. The method of claim 8 wherein the excess forward link capacity is a number of simultaneous calls.

10. A Code Division Multiple Access (CDMA) device comprising:

quadrature signal logic that is operational to receive and process quadrature components of the CDMA signal to generate a power control signal;

gain circuitry that is operational to automatically adjust a gain of the CDMA signal in response to the power control signal and;

a power monitor that is operational to monitor transmit power of the CDMA signal, and wherein the quadrature signal logic is further operational to process the quadrature components of the CDMA signal and determine a quadrature CDMA signal power value, to compare the quadrature CDMA signal power value to the transmit power, and to generate the power control signal based on the comparison.

11. The CDMA device of claim 10 wherein the quadrature signal logic is further operational to square a quadrature I component of the CDMA signal, to square a quadrature Q component of the CDMA signal, and to sum the squared quadrature I component of the CDMA signal and the squared quadrature Q component of the CDMA signal.

12. The CDMA device of claim 10 wherein the quadrature signal logic is further operational to determine a ratio of the transmit power to the quadrature CDMA signal power value, to compare the ratio to a pre-determined value, and to generate the power control signal to adjust the gain to change the ratio to be closer to the pre-determined value.

13. The CDMA device of claim 10 wherein the device is a multi-sector CDMA base station.

14. The CDMA device of claim 10 further comprising a cell site modem operational to generate the CDMA signal.

15. The CDMA device of claim 14 further comprising a digital-to-analog converter operational to convert the CDMA signal from digital to analog.

16. The CDMA device of claim 15 further comprising a low-pass filter operational to attenuate portions of the CDMA signal outside of a bandwidth.

17. The CDMA device of claim 16 further comprising an up-converter operational to convert the CDMA signal to a radio frequency CDMA signal.

18. The CDMA device of claim 17 further comprising a power amplifier operational to amplify the CDMA signal.

19. The CDMA device of claim 18 further comprising an antenna operational to transmit the CDMA signal.

20. The CDMA device of claim 10 wherein the quadrature signal logic is further operational to generate the power control signal without using information indicating per call gains.

21. The CDMA device of claim 10 wherein the quadrature signal logic is further operational to process the quadrature components of the CDMA signal to generate a capacity control signal.

22. The CDMA device of claim 21 wherein the capacity control signal indicates excess forward link capacity.

23. The CDMA device of claim 22 wherein the excess forward link capacity is a number of simultaneous calls.