Transmit power reduction for a wireless device with multiple transmit signal paths

• US 7,660,598 B2
• Filed: 12/21/2004
• Issued: 02/09/2010
• Est. Priority Date: 12/21/2004
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Barnett, Kenneth Charles, Peterzell, Paul, Persico, Charles J.
• Primary Examiner(s): TRINH, TAN H
• Application Number:
  US11/020,054
• Publication Number:
  US 20060135079A1
• Time in Patent Office: 1,876 Days
• Field of Search: 455/522, 455/69, 455/101, 455/81, 455/287, 455/103, 455/105, 455/63.1, 455/67.13, 455/62, 455/313, 455/522.1, 455/127.3, 455/127.4, 455/550.1, 455/442, 455/135, 370/334, 370/329, 375/344, 375/299, 375/146, 375/229, 375/267, 375/298
• US Class Current: 455/522
• CPC Class Codes: H04B 7/0404 the mobile station comprising multiple antennas, e.g. to provide uplink diversity
• CPC Class Codes: H04B 7/0608 Antenna selection according to transmission parameters
• CPC Class Codes: H04B 7/0619 using feedback from receiving side feedback signaling for adaptive modulation/coding H04L1/0001
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04W 52/221 using past power control commands
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

A wireless device is equipped with multiple (e.g., two) antennas, which may be of different designs. Each antenna interacts with the wireless environment in a different manner and achieves different scattering effect. The wireless device has one transmit signal path for each antenna. Each transmit signal path generates an RF output signal for transmission from the associated antenna. The wireless device controls the operation of one or more transmit signal paths to achieve a larger received signal level at a receiving base station. The wireless device may (1) autonomously adjust the transmit signal path(s) without relying on any feedback from the base station or (2) adjust the transmit signal path(s) based on transmit power control (TPC) commands received from the base station. The wireless device may selectively enable and disable each transmit signal path, vary the phase and/or gain of each transmit signal path, and so on.

Claims

1. A wireless device comprising:

a first transmit signal path operable to generate a first radio frequency (RF) output signal for transmission from a first antenna;

a second transmit signal path operable to generate a second RF output signal for transmission from a second antenna, the first and second antennas being transmit antennas and being de-correlated with respect to each other; and

a controller operable to selectively enable the first transmit signal path, the second transmit signal path, or both the first and second transmit signal paths to achieve a higher received signal level at a receiver, wherein the first and second transmit signal paths are selectively disabled based on transmit power control (TPC) commands received by the wireless device.

2. The wireless device of claim 1, wherein the controller is operable to enable the first transmit signal path at all times and to selectively enable and disable the second transmit signal path.

3. The wireless device of claim 1, wherein the controller is operable to selectively enable and disable the first transmit signal path, the second transmit signal path, or both the first and second transmit signal paths based on the transmit power control (TPC) commands received by the wireless device.

4. The wireless device of claim 3, wherein the controller is operable to select different configurations of the first and second transmit signal paths based on the received TPC commands, each configuration corresponding to a different set of at least one transmit signal path that is enabled.

5. The wireless device of claim 3, wherein the controller is operable to detect for a fade based on the received TPC commands and to select a different configuration of the first and second transmit signal paths whenever a fade is detected.

6. The wireless device of claim 5, wherein the controller detects a fade if a predetermined number of consecutive UP commands is received by the wireless device, each UP command being a TPC command to increase transmit power.

7. The wireless device of claim 5, wherein the controller detects a fade if a predetermined percentage, or higher, of TPC commands received by the wireless device within a time window is UP commands, each UP command being a TPC command to increase transmit power.

8. The wireless device of claim 1, wherein the first and second antennas are of different types.

9. The wireless device of claim 8, wherein the first antenna is a dipole antenna and the second antenna is a patch antenna.

10. The wireless device of claim 1, wherein the first transmit signal path is operable to provide a first output signal level and the second transmit signal path is operable to provide a second output signal level that is lower than the first output signal level.

11. A method of transmitting data, comprising:

generating a first radio frequency (RF) output signal for transmission from a first antenna at a wireless device;

generating a second RF output signal for transmission from a second antenna, the first and second antennas being transmit antennas and being de-correlated with respect to each other;

selectively enabling the generation of the first RF output signal, the second RF output signal, or both the first and second RF output signals to achieve a higher received signal level at a receiver, wherein the first and second RF output signals are selectively disabled based on transmit power control (TPC) commands received by the wireless device.

12. The method of claim 11, further comprising:

receiving the transmit power control (TPC) commands at the wireless device, and wherein the generation of the first RF output signal, the second RF output signal, or both the first and second RF output signals is selectively enabled based on the received TPC commands.

13. The method of claim 12, further comprising:

detecting for a fade based on the received TPC commands, and wherein a different set of at least one RF output signal is generated if the fade is detected.

14. A wireless apparatus, comprising:

means for generating a first radio frequency (RF) output signal for transmission from a first antenna;

means for generating a second RF output signal for transmission from a second antenna, the first and second antennas being transmit antennas and being de-correlated with respect to each other; and

means for selectively enabling the means for generating the first RF output signal, the means for generating the second RF output signal, or both the means for generating the first RF output signal and the means for generating the second RF output signal to achieve a higher received signal level at a receiver, wherein the first and second RF output signals are selectively disabled based on transmit power control (TPC) commands received by the wireless device.

15. A wireless device comprising:

a first transmit signal path operable to generate a first radio frequency (RF) output signal for transmission from a first antenna;

a second transmit signal path operable to generate a second RF output signal for transmission from a second antenna, the first and second antennas being transmit antennas and being de-correlated with respect to each other; and

a controller operable to autonomously adjust operation of the first transmit signal path, the second transmit signal path, or both the first and second transmit signal paths without feedback from a receiver receiving the first and second RF output signals, wherein the first and second transmit signal paths are selectively disabled based on transmit power control (TPC) commands received by the wireless device.

16. The wireless device of claim 15, wherein the second transmit signal path is operable to vary amplitude of the second RF output signal over time.

17. The wireless device of claim 15, wherein the second transmit signal path is operable to vary phase of the second RF output signal over time.

18. The wireless device of claim 15, wherein the controller is operable to alternately enable and disable the second transmit signal path over time.

19. The wireless device of claim 15, wherein the controller is operable to select different configurations of the first and second transmit signal paths over time.

20. The wireless device of claim 15, wherein the first and second antennas are of different types.

21. A wireless device comprising:

a first transmit signal path operable to generate a first radio frequency (RF) output signal;

a second transmit signal path operable to generate a second RF output signal;

a first antenna for transmitting the first RF output signal; and

a second antenna for transmitting the second RF output signal, the first and second antennas being transmit antennas and being de-correlated with respect to each other, wherein the first and second transmit signal paths are selectively disabled based on transmit power control (TPC) commands received by the wireless device.

22. The wireless device of claim 21, wherein the first antenna is a dipole antenna.

23. The wireless device of claim 21, wherein the second antenna is a patch antenna.

24. The wireless device of claim 21, wherein the first and second antennas have different polarizations.

25. The wireless device of claim 21, wherein the second transmit signal path is selectively enabled and disabled.

26. The wireless device of claim 25, wherein the second transmit signal path is selectively enabled and disabled based on the transmit power control (TPC) commands received by the wireless device.

27. The wireless device of claim 21, wherein the second transmit signal path comprises at least one circuit element operable to adjust phase, amplitude, or both amplitude and phase of the second RF output signal.

28. A wireless device comprising:

a first transmit signal path operable to generate a first radio frequency (RF) output signal having a first power level;

a second transmit signal path operable to generate a second RF output signal having a second power level that is lower than the first power level;

a first antenna for transmitting the first RF output signal; and

a second antenna for transmitting the second RF output signal, the first and second antennas being transmit antennas and being de-correlated with respect to each other, wherein the first and second transmit signal paths are selectively disabled based on transmit power control (TPC) commands received by the wireless device.

29. The wireless device of claim 28, further comprising:

an integrated circuit operable to receive baseband signals and generate a first RF modulated signal for the first transmit signal path and the second RF output signal for the second transmit signal path, the first RF modulated signal being further processed by the first transmit signal path to generate the first RF output signal.

30. The wireless device of claim 28, wherein the second RF output signal is at least three decibels (dB) lower than the first RF output signal.

31. The wireless device of claim 28, wherein the first and second antennas are of different types.

32. The wireless device of claim 28, wherein the second transmit signal path is selectively enabled and disabled.

33. An integrated circuit for a wireless device, comprising:

a modulator operable to receive baseband signals and generate a modulated signal;

a first amplifier operable to amplify the modulated signal and provide a first radio frequency (RF) modulated signal; and

a second amplifier operable to amplify the modulated signal and provide a second RF modulated signal, wherein the first and second RF modulated signals are designated for respective transmission from first and second antennas de-correlated with respect to each other, and wherein operation of the first amplifier, the second amplifier, or both the first and second amplifiers is controlled to achieve a higher received signal level at a receiver, wherein the first and second RF modulated signals are selectively disabled based on transmit power control (TPC) commands received by the wireless device.

34. The apparatus of claim 33, wherein the first amplifier, the second amplifier, or both the first and second amplifiers are selectively enabled and disabled based on the transmit power control (TPC) commands received by the wireless device from the receiver.

35. The apparatus of claim 33, wherein the second amplifier is selectively enabled and disabled autonomously without feedback from the receiver.

36. The apparatus of claim 33, wherein the first and second amplifiers are each controlled by varying gain, phase, or both gain and phase of the amplifier.