BASEBAND COMPENSATION FOR PHASE DISCONTINUITIES IN RADIO FREQUENCY COMMUNICATION DEVICES

• US 20110141930A1
• Filed: 08/27/2010
• Published: 06/16/2011
• Est. Priority Date: 12/11/2009
• Status: Abandoned Application

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Chellappa, Vijay K., Asuri, Bhushan Shanti, Verma, Sumit
• Application Number:
  US12/870,562
• Publication Number:
  US 20110141930A1
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04L 27/368 adaptive predistortion

Abstract

A method for compensating for phase discontinuities on a communication device is described. A communication device may determine a desired output power. The communication device may determine a Digital-to-Analog Converter (DAC) gain corresponding to the desired output power. The communication device may determine a cumulative phase offset based on the DAC gain. The communication device may apply the DAC gain. The communication device may apply a phase compensation to a rotator to adjust for the cumulative phase offset.

Claims

1. A method for compensating for phase discontinuities on a communication device, comprising:

determining a desired output power on a communication device;

determining, on the communication device, a Digital-to-Analog Converter (DAC) gain corresponding to the desired output power;

determining, on the communication device, a cumulative phase offset based on the DAC gain or the desired output power;

applying the DAC gain to the communication device; and

applying, on the communication device, a phase compensation to a rotator to adjust for the cumulative phase offset.

2. The method of claim 1, wherein the phase compensation is synchronized with the application of the DAC gain.

3. The method of claim 1, wherein the phase discontinuities occur as a result of applying the DAC gain to the communication device.

4. The method of claim 1, further comprising:

determining, on the communication device, a gain of transmitter components;

determining, on the communication device, the cumulative phase offset, wherein determining the cumulative phase offset is further based on the gain of the transmitter components;

applying the gain of the transmitter components to the communication device; and

applying, on the communication device, the phase compensation to the rotator to adjust for the cumulative phase offset that is further based on the gain of the transmitter components.

5. The method of claim 4, wherein the phase compensation is synchronized with the application of the gain of the transmitter components.

6. The method of claim 4, wherein the phase discontinuities occur as a result of applying the gain of the transmitter components to the communication device.

7. The method of claim 4, wherein the transmitter components comprise a baseband filter.

8. The method of claim 4, wherein the transmitter components comprise an upconverter.

9. The method of claim 4, wherein the transmitter components comprise a Voltage Controlled Oscillator/Phase Lock Loop (VCO/PLL).

10. The method of claim 4, wherein the transmitter components comprise a driver amplifier.

11. The method of claim 4, wherein the phase discontinuities occur as a result of activating or deactivating at least one of the transmitter components or as a result of activating or deactivating at least one sub-block of the transmitter components.

12. The method of claim 1, further comprising:

determining, on the communication device, a Power Amplifier (PA) gain;

determining, on the communication device, the cumulative phase offset, wherein determining the cumulative phase offset is further based on the PA gain;

applying the PA gain to the communication device; and

applying, on the communication device, the phase compensation to the rotator to adjust for the cumulative phase offset that is further based on the PA gain.

13. The method of claim 12, wherein the phase compensation is synchronized with the application of the PA gain.

14. The method of claim 12, wherein the phase discontinuities occur as a result of applying the PA gain to the communication device.

15. The method of claim 1, wherein the phase compensation is applied via a single phase compensation path in the baseband of the communication device.

16. The method of claim 1, wherein the phase compensation is fine phase compensation.

17. The method of claim 1, wherein the communication device is a wireless communication device.

18. The method of claim 1, wherein the communication device is a base station.

19. The method of claim 1, wherein the phase compensation is always applied.

20. A communication device configured to compensate for phase discontinuities, comprising:

a modulator configured for modulating a baseband signal, wherein the modulator comprises a rotator configured for rotating a phase of the baseband signal;

a Digital-to-Analog Converter (DAC) configured for converting a modulated digital signal to an analog signal; and

a transmit gain controller configured to control a DAC gain and to provide a phase offset to the rotator in the modulator in order to compensate for a phase shift in a transmission chain, wherein the transmit gain controller selects the DAC gain and phase offset based on a desired output power.

21. The communication device of claim 20, wherein the phase offset is provided synchronously with the control of the DAC gain.

22. The communication device of claim 20, wherein the phase discontinuities occur as a result of controlling the DAC gain.

23. The communication device of claim 20, further comprising:

transmitter components configured to format a signal for transmission; and

wherein

the transmit gain controller is further configured to control a gain of the transmitter components and to provide the phase offset to the rotator in the modulator in order to compensate for the phase shift in the transmission chain, wherein the transmit gain controller further selects the gain of the transmitter components based on the desired output power.

24. The communication device of claim 23, wherein the phase offset is provided synchronously with the control of the gain of the transmitter components.

25. The communication device of claim 23, wherein the phase discontinuities occur as a result of controlling the gain of the transmitter components.

26. The communication device of claim 23, wherein the transmitter components comprise a baseband filter.

27. The communication device of claim 23, wherein the transmitter components comprise an upconverter.

28. The communication device of claim 23, wherein the transmitter components comprise a Voltage Controlled Oscillator/Phase Lock Loop (VCO/PLL).

29. The communication device of claim 23, wherein the transmitter components comprise a driver amplifier.

30. The communication device of claim 23, wherein the phase discontinuities occur as a result of activating or deactivating at least one of the transmitter components or as a result of activating or deactivating at least one sub-block of the transmitter components.

31. The communication device of claim 20, further comprising:

a power amplifier (PA) configured to amplify a signal for transmission; and

wherein

the transmit gain controller is further configured to control a PA gain and to provide the phase offset to the rotator in the modulator in order to compensate for the phase shift in the transmission chain, wherein the transmit gain controller further selects the PA gain based on the desired output power.

32. The communication device of claim 31, wherein the phase offset is provided synchronously with the control of the PA gain.

33. The communication device of claim 31, wherein the phase discontinuities occur as a result of controlling the PA gain.

34. The communication device of claim 20, wherein the compensation for the phase shift is applied via a single phase compensation path in the baseband of the communication device.

35. The communication device of claim 20, wherein the compensation for the phase shift is fine phase compensation.

36. The communication device of claim 20, wherein the communication device is a wireless communication device.

37. The communication device of claim 20, wherein the communication device is a base station.

38. The communication device of claim 20, wherein the compensation for the phase offset is always applied.

39. A computer-program product for compensating for phase discontinuities on a communication device, the computer-program product comprising a non-transitory tangible computer-readable medium having instructions thereon, the instructions comprising:

code for determining a desired output power;

code for determining a Digital-to-Analog Converter (DAC) gain corresponding to the desired output power;

code for determining a cumulative phase offset based on the DAC gain;

code for applying the DAC gain; and

code for applying a phase compensation to a rotator to adjust for the cumulative phase offset.

40. A communication device configured to compensate for phase discontinuities, comprising:

means for determining a desired output power on a communication device;

means for determining, on the communication device, a Digital-to-Analog Converter (DAC) gain corresponding to the desired output power;

means for determining, on the communication device, a cumulative phase offset based on the DAC gain or the desired output power;

means for applying the DAC gain to the communication device; and

means for applying, on the communication device, a phase compensation to a rotator to adjust for the cumulative phase offset.