WCDMA Power Saving with Transmit Diversity

• US 20080151798A1
• Filed: 12/22/2006
• Published: 06/26/2008
• Est. Priority Date: 12/22/2006
• Status: Active Grant

• Current Assignee: Sony Mobile Communications AB (Sony Group Corp.)
• Original Assignee: Sony Ericsson Mobile Communications USA Incorporated (Sony Group Corp.)
• Inventors: Camp, William O.
• Granted Patent: US 9,590,715 B2
• Time in Patent Office: Days
• US Class Current: 370/311
• CPC Class Codes: H04B 1/1615 Switching on; Switching off, e.g. remotely battery saving circuits associated with selective call operation H04W52/00; details of power consumption reduction in a PLL, H03L7/0802, H03L7/14, H03L2207/08, H03L2207/18; muting amplifiers by gain control see H03G3/34
• CPC Class Codes: H04B 7/0404 the mobile station comprising multiple antennas, e.g. to provide uplink diversity
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas
• CPC Class Codes: H04B 7/0693 switching off a diversity branch, e.g. to save power
• CPC Class Codes: H04W 52/0232 according to average transmission signal activity
• CPC Class Codes: H04W 52/20 using error rate
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A mobile terminal reduces its power consumption by selectively switching between a diversity mode and a non-diversity mode. The mobile terminal monitors the total output power of two or more of its transmitters, and selectively switches between the diversity mode and the non-diversity mode based on the total output power. The mobile terminal may also selectively switch between the diversity and non-diversity modes based on a difference in output power levels between the two or more transmitters.

Claims

1. A method of reducing power consumption in a code division multiple access terminal having first and second transmitters, the method comprising:

calculating a total output power level for first and second transmitters; and

switching between transmitting in a diversity mode and a non-diversity mode based on the total output power level.

2. The method of claim 1 wherein switching between transmitting in a diversity mode and a non-diversity mode comprises enabling both the first and second transmitters if the total output power level exceeds a predetermined power level.

3. The method of claim 1 further comprising adjusting the total output power to maintain a desired target error rate.

4. The method of claim 1 wherein switching between transmitting in a diversity mode and a non-diversity mode comprises disabling one of the first and second transmitters if the total output power level falls below a predetermined power level.

5. The method of claim 4 wherein disabling one of the first and second transmitters comprises disabling the transmitter with the least favorable channel conditions.

6. The method of claim 4 wherein disabling one of the first and second transmitters comprises disabling the transmitter with the lowest output power.

7. The method of claim 1 further comprising computing a difference between the output power levels of the first and second transmitters if the total output power level falls below a predetermined power level.

8. The method of claim 7 wherein switching between transmitting in a diversity mode and a non-diversity mode comprises enabling both the first and second transmitters if the total output power level exceeds a predetermined power level and the computed difference falls below a predetermined value.

9. The method of claim 7 wherein switching between transmitting in a diversity mode and a non-diversity mode comprises disabling one of the first and second transmitters if the total output power level falls below a predetermined power level and the computed difference exceeds a predetermined value.

10. The method of claim 9 wherein disabling one of the first and second transmitters comprises disabling the transmitter with the least favorable channel conditions.

11. The method of claim 9 wherein disabling one of the first and second transmitters comprises disabling the transmitter with the lowest output power.

12. A method of reducing power consumption in a code division multiple access terminal having first and second transmitters, the method comprising:

computing a difference between output power levels of first and second transmitters; and

switching between a diversity mode and a non-diversity mode based on the computed difference.

13. The method of claim 12 further comprising adjusting the total output power to maintain a desired target error rate.

14. The method of claim 12 wherein switching between transmitting in a diversity mode and a non-diversity mode comprises enabling both the first and second transmitters if the computed difference exceeds a predetermined value.

15. The method of claim 12 wherein switching between transmitting in a diversity mode and a non-diversity mode comprises disabling one of the first and second transmitters if the computed difference falls below a predetermined value.

16. The method of claim 15 wherein disabling one of the first and second transmitters comprises disabling the transmitter with the least favorable channel conditions.

17. The method of claim 15 wherein disabling one of the first and second transmitters comprises disabling the transmitter with the lowest output power.

18. A code division multiple access terminal comprising:

first and second transmitters configured to transmit signals; and

a control circuit configured to;

calculate a total output power level for the first and second transmitters; and

selectively enable and disable the first and second transmitters based on the total output power level to switch between a diversity mode and a non-diversity mode.

19. The terminal of claim 18 wherein the control circuit is further configured to adjust the total output power to maintain a desired target error rate.

20. The terminal of claim 18 wherein the control circuit is configured to enable both the first and second transmitters if the total output power level exceeds a predetermined power level.

21. The terminal of claim 18 wherein the control circuit is configured to selectively disable one of the first and second transmitters if the total output power level falls below a predetermined power level.

22. The terminal of claim 21 wherein the control circuit is configured to selectively disable the transmitter with the least favorable channel conditions.

23. The terminal of claim 21 wherein the control circuit is configured to selectively disable the transmitter with the lowest output power.

24. The terminal of claim 18 wherein the control circuit is further configured to:

compute a difference between the output power levels of the first and second transmitters if the total output power level falls below a predetermined power level; and

selectively enable and disable the first and second transmitters based on the total output power level and on the computed difference to switch between the diversity mode and the non-diversity mode.

25. The terminal of claim 24 wherein the control circuit is configured to enable both the first and second transmitters if the total output power level exceeds a predetermined power level and if the computed difference falls below a predetermined value.

26. The terminal of claim 24 wherein the control circuit is configured to disable one of the first and second transmitters if the total output power level falls below a predetermined power level and if the computed difference exceeds a predetermined value.

27. The terminal of claim 26 wherein the control circuit is configured to selectively disable the transmitter with the least favorable channel conditions.

28. The terminal of claim 26 wherein the control circuit is configured to selectively disable the transmitter with the lowest output power.

29. A code division multiple access terminal comprising:

first and second transmitters to transmit signals; and

a control circuit configured to;

compute a difference between output power levels of the first and second transmitters; and

selectively enable and disable the first and second transmitters based on the computed difference to switch between the diversity mode and the non-diversity mode.

30. The terminal of claim 29 wherein the control circuit is configured to enable both the first and second transmitters if the computed difference exceeds a predetermined value.

31. The terminal of claim 29 wherein the control circuit is configured to disable one of the first and second transmitters if the computed difference falls below a predetermined value.

32. The terminal of claim 31 wherein the control circuit is configured to selectively disable the transmitter with the least favorable channel conditions.

33. The terminal of claim 31 wherein the control circuit is configured to selectively disable the transmitter with the lowest output power.

34. The terminal of claim 29 wherein the control circuit is further configured to adjust the output power levels of one or both of the first and second transmitters to maintain a desired target error rate.