Method and apparatus for congestion control in a wireless communication system

• US 20020193118A1
• Filed: 06/07/2001
• Published: 12/19/2002
• Est. Priority Date: 06/07/2001
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Jain, Avinash, Holtzman, Jack M.
• Granted Patent: US 6,983,153 B2
• Time in Patent Office: Days
• US Class Current: 455/453
• CPC Class Codes: H04B 7/264 for data rate control
• CPC Class Codes: H04W 28/12 using signalling between network elements
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 4/24 Accounting or billing

Abstract

Method and apparatus for congestion control in a wireless communication system. In one embodiment, the status of a congestion bit indicates the type of adjustment, such as increase or decrease, to be performed at an access terminal to determine the next data rate for transmissions on the reverse link. The status of the congestion bit is determined by comparing a congestion parameter to a predetermined threshold. One embodiment implements an outerloop threshold having a margin with respect to the desired congestion metric threshold. The outerloop threshold is adjusted in response to comparing a measured congestion metric to the desired threshold. The outerloop threshold adjustment maintains the congestion metric to within a predetermined probability of exceeding the desired threshold.

Claims

1. A method for generating a congestion indicator, comprising:

determining an outerloop threshold as a function of a desired threshold, measuring a congestion metric;

comparing the congestion metric to the desired threshold; and

updating the outer loop threshold in response to comparing the measured congestion metric to the desired threshold.

2. The method as in claim 1, wherein the congestion metric is a Rise-Over-Thermal measurement.

3. The method as in claim 1, further comprising:

Comparing the congestion metric to the outerloop threshold; and

transmitting a congestion indicator in response to comparing the congestion metric to the outerloop threshold.

4. The method as in claim 1, wherein updating the outerloop threshold further comprises:

subtracting a first value Δ

from the outerloop threshold in response to a first result of comparing the congestion metric to the desired threshold; and

subtracting a second value δ

from the outerloop threshold in response to a second result of comparing the congestion metric to the desired threshold.

5. The method as in claim 4, wherein a ratio of Δ

to δ

corresponds to a probability of exceeding the desired threshold of the congestion metric.

6. In a wireless communication system, an apparatus, comprising:

congestion metric measurement unit operative measure a congestion metric of the wireless system; and

outerloop threshold adjustment unit operative to determine an outerloop threshold as a function of a desired threshold.

7. The apparatus as in claim 6, further comprising:

a comparator coupled to the congestion metric measurement unit and the outerloop threshold adjustment unit, operative to determine a next congestion indicator in response to comparing a measured congestion metric to the outerloop threshold.

8. The apparatus as in claim 6, further comprising:

a second comparator coupled to the congestion metric measurement unit and the outerloop threshold adjustment unit, operative to compare the measured congestion metric to a desired threshold, wherein the outerloop threshold adjustment unit adjusts the outerloop threshold in response to the second comparator.

9. The apparatus as in claim 8, wherein the outerloop threshold adjustment unit comprises:

first means for adjusting the outerloop threshold by subtracting a first value Δ

from the outerloop threshold in response to a first result of comparing the congestion metric to the desired threshold; and

second means for adjusting the outerloop threshold by subtracting a second value δ

from the outerloop threshold in response to a second result of comparing the congestion metric to the desired threshold,

wherein a ratio of Δ

to δ

corresponds to a probability of exceeding the desired threshold of the congestion metric.

10. The apparatus as in claim 9, wherein the first means is a set of computer-readable instructions stored on a computer-readable storage unit, and the second means is a second set of computer-readable instructions stored on the computer-readable storage unit.

11. The apparatus as in claim 9, wherein the outerloop threshold adjustment unit initializes the outerloop threshold to the desired threshold.

12. The apparatus as in claim 9, wherein the outerloop threshold adjustment unit determines the outerloop threshold having a predetermined margin with respect to the desired threshold.