Method and system for precise transmit power adjustment in wireless communication systems

• US 8,204,460 B2
• Filed: 08/08/2007
• Issued: 06/19/2012
• Est. Priority Date: 08/08/2007
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Rajagopal, Sridhar, Joseph, Brian Chadwick
• Primary Examiner(s): Aminzay, Shaima Q
• Application Number:
  US11/835,924
• Publication Number:
  US 20090042525A1
• Time in Patent Office: 1,777 Days
• Field of Search: 455/232.1, 455/522, 455/69, 455/13.4, 455/127.1, 455/233.1, 455/234.1, 455/240.1, 455/127.2, 455/126, 455/127.5, 370/318, 375/219, 375/297, 330/124.R
• US Class Current: 455/127.2
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04
• CPC Class Codes: H04B 2001/0416 having gain or transmission power control
• CPC Class Codes: H04W 52/36 with a discrete range or set of values, e.g. step size, ramping or offsets
• CPC Class Codes: H04W 52/362 Aspects of the step size
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

A method for precise transmit power adjustment in a wide personal area network (WPAN) is provided that includes coarse adjusting a power level of the radio signal by adjusting a gain setting of an amplifier that is used to power the radio signal, and fine adjusting the power level of the radio signal by adjusting a voltage level of an information signal that is provided to the amplifier so that the power level of the radio signal approaches a maximum allowable power level.

Claims

1. A method for precise transmit power adjustment of a radio signal, the method comprising:

coarse adjusting a power level of the radio signal by adjusting a gain setting of an amplifier that is used to power the radio signal; and

fine adjusting the power level of the radio signal by adjusting a voltage level of an information signal that is provided to the amplifier so that the power level of the radio signal approaches a maximum allowable power level.

2. The method of claim 1, wherein the fine adjusting the voltage level of the information signal includes adjusting an output voltage level of a digital-to-analog converter (DAC), the DAC is configured to generate the information signal.

3. The method of claim 1, wherein the fine adjusting the voltage level of the information signal includes scaling a digital baseband signal that is provided to a DAC, the DAC configured to generate the information signal from the digital baseband signal.

4. The method of claim 3, wherein the scaling is performed via a digital multiplier.

5. The method of claim 1, further comprising:

detecting by a sensor a change in the power level of the radio signal during operation; and

performing coarse and fine adjustments to the power level of the radio signal to compensate for the change in the power level of the radio signal during operation.

6. The method of claim 5, wherein the detecting by the sensor the change in the power level of the radio signal during operation includes:

detecting by a temperature sensor a change in an operating temperature of the amplifier; and

determining, via a data table, the change in the power level of the radio signal that corresponds to the detected change in the operating temperature of the amplifier;

wherein the data table includes data representing the output power level of the amplifier over a temperature range.

7. The method of claim 5, wherein the detecting by the sensor the change in the power level of the radio signal during operation includes:

wherein the detecting by the sensor the change in the power level of the radio signal during operation includes detecting by a voltage sensor a change in a voltage level of the radio signal during operation; and

determining the change in the power level of the radio signal that corresponds to the detected change in the voltage level of the radio signal.

8. The method of claim 5, wherein the detecting by the sensor the change in the power level of the radio signal during operation includes detecting by a power sensor the change in the power level of the radio signal during operation.

9. The method of claim 1, wherein the amplifier is configured to include an output power level with a dynamic range of about 20 dB and a step size of about 1-2 dB.

10. The method of claim 9, wherein the fine adjusting the power level of the radio signal includes a gain resolution of about 0.04 to 0.25 dB step size.

11. The method of claim 1, wherein the radio signal is an orthogonal frequency-division multiplexed (OFDM) signal.

12. A non-transitory computer-readable medium having computer-executable instructions for precise transmit power adjustment of a radio signal, comprising:

instructions for coarse adjusting a power level of the radio signal by adjusting a gain setting of an amplifier that is used to power the radio signal; and

instructions for fine adjusting the power level of the radio signal by adjusting a voltage level of an information signal that is provided to the amplifier so that the power level of the radio signal approaches a maximum allowable power level.

13. The non-transitory computer-readable medium of claim 12, wherein the instructions for fine adjusting the voltage level of the information signal includes adjusting an output voltage level of a digital-to-analog converter (DAC), the DAC is configured to generate the information signal.

14. The non-transitory computer-readable medium of claim 12, wherein the instructions for fine adjusting the voltage level of the information signal includes scaling a digital baseband signal that is provided to a DAC, the DAC configured to generate the information signal from the digital baseband signal.

15. The non-transitory computer-readable medium of claim 12;

further comprising;

instructions for detecting by a sensor a change in the power level of the radio signal during operation; and

instructions for performing the coarse and fine adjustments to the power level of the radio signal to compensate for the change in the power level of the radio signal.

16. The non-transitory computer-readable medium of claim 15, wherein the instructions for detecting by the sensor the change in the power level of the radio signal during operation includes:

instructions for detecting by a temperature sensor a change in an operating temperature of the amplifier; and

instructions for determining, via a data table, the change in the power level of the radio signal that corresponds to the change in the operating temperature of the amplifier;

wherein the data table represents an output power level of the amplifier over a temperature range.

17. The non-transitory computer-readable medium of claim 15, wherein the instructions for detecting by the sensor the change in the power level of the radio signal during operation includes:

instructions for detecting by a voltage sensor a change in a voltage level of the radio signal during operation; and

instructions for determining the change in the power level of the radio signal that corresponds to the detected change in the voltage level of the radio signal.

18. The non-transitory computer-readable medium of claim 15, wherein the instructions for detecting by the sensor the change in the power level of the radio signal during operation includes detecting by a power sensor the change in the power level of the radio signal during operation.

19. The non-transitory computer-readable medium of claim 12, further comprising:

instructions for determining a change in the power level of the radio signal when switching from a first antenna to a second antenna for transmitting the radio signal; and

instructions for compensating for the change in the power level corresponding to the switch.

20. A system for precise transmit power adjustment, comprising:

a digital multiplier for providing a digital baseband signal;

a digital-to-analog converter (DAC) coupled to the digital multiplier, the DAC receiving the digital baseband signal and generating an information signal;

an amplifier coupled to the DAC, the amplifier receiving the information signal and powering a radio signal, the amplifier having a gain setting that controls an output power level of the amplifier; and

a memory having instructions for coarse adjusting a power level of the radio signal by adjusting the gain setting of the amplifier, and instructions for fine adjusting the power level of the radio signal by adjusting a voltage level of the information signal so that the power level of the radio signal approaches a maximum allowable power level.

21. The system of claim 20, further comprising at least one antenna coupled to the amplifier, the at least one antenna configured to transmit the radio signal;

wherein the memory further includes instructions for determining a change in the power level of the radio signal when the system switches from a first antenna to a second antenna for transmitting the radio signal, and instructions for compensating for the change in the power level corresponding to the switch.

22. The system of claim 20, wherein the memory having instructions for fine adjusting the power level of the radio signal includes instructions for fine adjusting the power level of the radio signal by adjusting an output voltage level of the DAC.

23. The system of claim 20, wherein the memory having instructions for fine adjusting the power level of the radio signal includes instructions for fine adjusting the power level of the radio signal by scaling the digital baseband signal via the digital multiplier.

24. The system of claim 20, further comprising a sensor for detecting a change in the power level of the radio signal during operation;

wherein the memory further includes instructions for coarse and fine adjustments to the power level of the radio signal to compensate for the detected change in the power level of the radio signal during operation.

25. The system of claim 24,

wherein the sensor includes a temperature sensor for detecting a change in an operating temperature of the amplifier;

wherein the memory further includes instructions for determining, via a data table, the change in the power level of the radio signal that corresponds to the detected change in the operating temperature of the amplifier; and

wherein the data table represents a relationship between the output power level of the amplifier over a temperature range.

26. The system of claim 24, wherein the sensor includes a power sensor for detecting the change in the power level of the radio signal during operation.

27. The system of claim 24,

wherein the sensor includes a voltage sensor for detecting a change in a voltage level of the radio signal during operation;

and

wherein the memory further includes instructions for determining the change in the power level of the radio signal that corresponds to the change in the voltage level of the radio signal.

28. The system of claim 20, wherein the amplifier is configured to have an output power level with a dynamic range of about 20 dB.

29. The system of claim 20, wherein the radio signal is an orthogonal frequency division multiplexed (OFDM) signal.

30. An apparatus for precise transmit power adjustment of a radio signal, comprising:

means for coarse adjusting a power level of the radio signal by adjusting a gain setting of an amplifier that is used to power the radio signal; and

means for adjusting the power level of the radio signal by adjusting a voltage level of an information signal that is provided to the amplifier so that the power level of the radio signal approaches a maximum allowable power level.