Power control outer loop for communication channels with discontinuous transmission (DTX)

• US 20030142632A1
• Filed: 01/31/2002
• Published: 07/31/2003
• Est. Priority Date: 01/31/2002
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Lin, Yu-Chuan, Saints, Keith W., Yoon, Steven
• Granted Patent: US 6,731,606 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04W 52/12 Outer and inner loops
• CPC Class Codes: H04W 52/20 using error rate
• CPC Class Codes: H04W 52/225 Calculation of statistics, e.g. average, variance
• CPC Class Codes: H04W 52/26 using transmission rate or quality of service QoS [Quality of Service]
• CPC Class Codes: H04W 52/287 when the channel is in stand-by
• CPC Class Codes: H04W 52/44 in connection with interruption of transmission

Abstract

Novel techniques are disclosed for adjusting a power control setpoint to compensate for imperfect signal detection in a communication channel capable of discontinuous transmission (DTX). The power control setpoint is compensated for false detections by adjusting the power control setpoint by a dynamically determined setpoint back off amount upon detection of a Good frame. The amount of the setpoint back off is a function of the measured signal quality of the detected Good frame and the number of Erasure indications received immediately preceding the Good frame indication.

Claims

1. In a communication device having discontinuous transmission (DTX) detection, a method of providing outer loop power control comprising:

estimating a number of erroneous frame detections; and

adjusting a power control setpoint associated with the outer loop power control wherein the adjustment is determined at least in part by the estimated number of erroneous frame detections.

2. The method of claim 1, wherein the erroneous frame detections are Erasure detections.

3. The method of claim 1, further comprising detecting a Good frame and wherein adjusting the power control setpoint occurs in response to detecting the Good frame.

4. The method of claim 3, wherein the number of erroneous frame detections is a number of Erasure detections occurring between successive Good frame detections.

5. The method of claim 4, wherein the adjustment to the power control setpoint is zero if the number of Erasure detections is less than a predetermined threshold.

6. The method of claim 5, wherein the predetermined threshold is a constant.

7. The method of claim 5, wherein the predetermined threshold is 10.

8. The method of claim 3, wherein the power control setpoint is adjusted to equal the minimum of:

a historic setpoint; and

a Signal to Noise Ratio (SNR) plus a predetermined margin.

9. The method of claim 8, wherein the SNR is a measured value.

10. The method of claim 8, wherein the SNR is a E_b/N_t value of the detected Good frame.

11. The method of claim 8, wherein the current setpoint and SNR are in units of dB and the predetermined margin is substantially 2 dB.

12. The method of claim 1, wherein adjusting the power control setpoint comprises:

setting the power control setpoint to the maximum of a predetermined minimum setpoint value and a current setpoint value, if the number of erroneous frame detections equals or exceeds a predetermined threshold; and

setting the power control setpoint to the current setpoint value, if the number of erroneous frame detections is less than the predetermined threshold value.

13. The method of claim 1, wherein the outer loop power control is reverse outer loop power control.

14. The method of claim 1, wherein the outer loop power control is forward outer loop power control.

15. The method of claim 1, wherein the communication device is one of a CDMA base station, a CDMA base station controller, and a CDMA mobile station.

16. In a communication device having discontinuous transmission (DTX) detection, a method of providing outer loop power control comprising:

estimating a number of erroneous Erasure detections;

detecting a Good frame; and

in response to detecting the Good frame indication, adjusting a power control setpoint associated with the outer loop power control wherein the adjustment comprises;

detecting a frame sequence number in the detected Good frame; and

setting the setpoint to a dynamically determined setpoint backoff value determined in part on the estimated number of Erasure detections if the frame sequence number is not continuous with a prior frame sequence number.

17. A wireless communication device having discontinuous transmission (DTX) detection and outer loop power control comprising:

means for estimating a number of erroneous frame detections; and

means for adjusting a power control setpoint associated with the outer loop power control wherein the adjustment is determined at least in part by the number of erroneous frame detections.

18. The device of claim 17, wherein the erroneous frame detections are Erasure detections.

19. The device of claim 17, further comprising means for detecting a Good frame and wherein the means for adjusting the power control setpoint responds to the means for detecting the Good frame.

20. The device of claim 19, wherein the means for estimating the number of erroneous frame detections counts a number of Erasure detections occurring between successive Good frame detections.

21. The device of claim 20, wherein the adjustment to the power control setpoint is zero if the number of Erasure detections is less than a predetermined threshold.

22. The device of claim 21, wherein the predetermined threshold is a constant.

23. The device of claim 21, wherein the predetermined threshold is 10.

24. The device of claim 19, wherein the means for adjusting the power control setpoint adjusts the power control setpoint to equal the minimum of:

a historic setpoint; and

a Signal to Noise Ratio (SNR) plus a predetermined margin.

25. The device of claim 24, wherein the SNR is a measured value.

26. The device of claim 24, wherein the SNR is a E_b/N_t value of the detected good frame.

27. The device of claim 24, wherein the current setpoint and SNR are in units of dB and the predetermined margin is substantially 2 dB.

28. The device of claim 17, wherein the means for adjusting the power control setpoint comprises:

means for setting the power control setpoint to the maximum of a predetermined minimum setpoint value and a current setpoint value if the number of erroneous frame detections equals or exceeds a predetermined threshold; and

means for setting the power control setpoint to the current setpoint value if the number of erroneous frame detections is less than the predetermined threshold value.

29. The device of claim 17, wherein the outer loop power control is reverse outer loop power control.

30. The device of claim 17, wherein the outer loop power control is forward outer loop power control.

31. The device of claim 17, wherein the wireless communication device is one of a CDMA base station, a CDMA base station controller, and a CDMA mobile station.