Method and apparatus for setting the threshold of a power control target in a spread spectrum communication system

• US 20040203462A1
• Filed: 11/25/2002
• Published: 10/14/2004
• Est. Priority Date: 11/25/2002
• Status: Abandoned Application

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Shen, Chiang-Hwa, Lin, Wei, Lee, Yuan Kang
• Application Number:
  US10/303,189
• Publication Number:
  US 20040203462A1
• Time in Patent Office: Days
• US Class Current: 455/67.13
• CPC Class Codes: H04W 52/12 Outer and inner loops
• CPC Class Codes: H04W 52/26 using transmission rate or quality of service QoS [Quality of Service]
• CPC Class Codes: H04W 52/36 with a discrete range or set of values, e.g. step size, ramping or offsets

Abstract

A communication system and method for revising an updated target signal to interference ratio (SIR) ensure that the updated target SIR does not fall below a threshold target SIR that is required to ensure a specified minimum quality of service. In one aspect, the present invention provides a method for controlling an updated target signal to interference ratio in a communication system. In this method 180, an updated target signal to interference ratio is received (block 182). A threshold signal to interference ratio is established (block 184) and the updated target signal to interference ratio and the threshold signal to interference ratio are compared (block 186). The updated target signal to interference ratio is then set equal to the threshold signal to interference ratio if the updated target signal to interference ratio is less than the threshold signal to interference ratio (block 188).

Claims

1. A process for controlling an updated target signal to interference ratio in a communication system, the process comprising:

receiving an updated target signal to interference ratio;

establishing a threshold signal to interference ratio;

comparing the updated target signal to interference ratio and the threshold signal to interference ratio; and

setting the updated target signal to interference ratio equal to the threshold signal to interference ratio if the updated target signal to interference ratio is less than the threshold signal to interference ratio.

2. A process in accordance with claim 1, wherein the communication system comprises a multi-data rate communication system and wherein establishing the threshold signal to interference ratio comprises:

establishing a minimum signal to interference ratio for each possible data transmission rate; and

setting the threshold signal to interference ratio equal to the maximum of the minimum signal to interference ratios.

3. A process in accordance with claim 2, wherein establishing the threshold signal to interference ratio further comprises increasing the threshold signal to interference ratio by an signal to interference ratio enhancement factor.

4. A process in accordance with claim 3, wherein the signal to interference ratio enhancement factor is received from a remote device.

5. A process in accordance with claim 1, wherein establishing the threshold signal to interference ratio comprises:

establishing a minimum signal to interference ratio for each possible data transmission rate;

weighting each minimum signal to interference ratio; and

combining together each of the weighted minimum signal to interference ratios, thereby generating the threshold signal to interference ratio.

6. A process in accordance with claim 5, wherein each minimum signal to interference ratio is weighted according to a probability of a respective possible data transmission rate.

7. A process in accordance with claim 5, wherein establishing the threshold signal to interference ratio further comprises modifying the threshold signal to interference ratio based on a signal to interference ratio enhancement factor.

8. A process in accordance with claim 7, wherein the signal to interference ratio enhancement factor is received from a remote device.

9. A process in accordance with claim 1, and further comprising computing the updated target signal to interference ratio prior to receiving the updated target signal to interference ratio.

10. A handheld communication device comprising:

an antenna;

a signal input/output section coupled to the antenna;

a user interface; and

a processor, the processor coupled to the signal input/output section and the user interface, wherein

the processor is adapted to receive an updated target signal to interference ratio;

the processor is adapted to establish a threshold signal to interference ratio;

the processor is adapted to compare the updated target signal to interference ratio and the threshold signal to interference ratio; and

the processor is adapted to set the updated target signal to interference ratio equal to the threshold signal to interference ratio if the updated target signal to interference ratio is less than the threshold signal to interference ratio.

11. An apparatus in accordance with claim 10, wherein the processor is adapted to establish a threshold signal to interference ratio by establishing a minimum signal to interference ratio for each possible data transmission rate, and setting the threshold signal to interference ratio equal to the maximum of the minimum signal to interference ratios.

12. An apparatus in accordance with claim 11, wherein the processor is further adapted to increase the threshold signal to interference ratio by the signal to interference ratio enhancement factor.

13. An apparatus in accordance with claim 10, wherein the processor is adapted to establish a threshold signal to interference ratio by establishing a minimum signal to interference ratio for each possible data transmission rate and taking the weighted average of the minimum signal to interference ratios.

14. An apparatus in accordance with claim 13 wherein each minimum signal to interference ratio is weighted according to a probability of a respective possible data transmission rate.

15. An apparatus for use in a spread-spectrum, multi-data rate communication system, the apparatus comprising:

means for comparing an updated target signal to interference ratio (SIR) to a threshold SIR; and

means for setting the updated target SIR equal to the threshold SIR if the updated target SIR is less than the threshold SIR.

16. The apparatus of claim 15 and further comprising means for establishing the threshold SIR, the means for establishing comprising:

means for establishing a minimum SIR for each possible data transmission rate; and

means for setting the threshold SIR equal to the maximum of the minimum SIRs.

17. The apparatus of claim 16 wherein the means for establishing the threshold SIR further comprises means for increasing the threshold SIR by an SIR enhancement factor.

18. The apparatus of claim 17 and further comprising means for receiving the SIR enhancement factor from a remote device.

19. The apparatus of claim 15 and further comprising means for establishing the threshold SIR, the means for establishing comprising:

means for establishing a minimum signal to interference ratio for each possible data transmission rate;

means for weighting each minimum signal to interference ratio; and

means for combining together each of the weighted minimum signal to interference ratios, thereby generating the threshold signal to interference ratio.

20. The apparatus of claim 19 wherein each minimum signal to interference ratio is weighted according to a probability of a respective possible data transmission rate.