Weighted-Fairness in Message Rate Based Congestion Control for Vehicular Systems

• US 20140119210A1
• Filed: 10/30/2012
• Published: 05/01/2014
• Est. Priority Date: 10/30/2012
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Bansal, Gaurav, Kenney, John
• Granted Patent: US 8,948,044 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback
• CPC Class Codes: H04W 28/021 in wireless networks with changing topologies, e.g. ad-hoc networks self-organizing networks H04W84/18

Abstract

A system and method for implementing congestion control for vehicles based at least in part on weighted fair message rates is disclosed. The system comprises a measurement module, a calculation module and a determination module. The measurement module measures a channel busy ratio describing a fraction of time during which a channel is busy. The calculation module calculates a ratio error by comparing the measured channel busy ratio with a target channel busy ratio. The determination module determines a first parameter value for a first vehicle based at least in part on a ratio of weights and determines a message rate for the first vehicle based at least in part on the ratio error and the first parameter value. The message rate describes a speed for transmitting messages from the first vehicle.

Claims

1. A computer-implemented method, comprising:

measuring a channel busy ratio describing a fraction of time during which a channel is busy;

calculating a ratio error by comparing the measured channel busy ratio with a target channel busy ratio;

determining a first parameter value for a first vehicle based at least in part on a ratio of weights; and

determining a message rate for the first vehicle based at least in part on the ratio error and the first parameter value, the message rate describing a speed for transmitting messages from the first vehicle.

2. The method of claim 1, wherein determining the first parameter value for the first vehicle further comprises:

determining a parameter ratio based at least in part on the ratio of weights; and

determining the first parameter value for the first vehicle based at least in part on the parameter ratio.

3. The method of claim 2, wherein the parameter ratio describes a proportion between the first parameter value for the first vehicle and a second parameter value for a second vehicle.

4. The method of claim 2, wherein the parameter ratio equals to the ratio of weights.

5. The method of claim 2, wherein determining of the first parameter value for the first vehicle is further based at least in part on a type of the first vehicle.

6. The method of claim 1, wherein determining the message rate for the first vehicle further comprises determining the message rate for the first vehicle recursively so that the message rate for the first vehicle converges to a steady state message rate based at least in part on the ratio of weights.

7. The method of claim 1, wherein determining the message rate for the first vehicle further comprises:

determining a sign of the ratio error; and

determining the message rate for the first vehicle based at least in part on the sign of the ratio error.

8. A system comprising:

a measurement module for measuring a channel busy ratio describing a fraction of time during which a channel is busy;

a calculation module communicatively coupled to the measurement module, the calculation module calculating a ratio error by comparing the measured channel busy ratio with a target channel busy ratio; and

a determination module communicatively coupled to the calculation module, the determination module determining a first parameter value for a first vehicle based at least in part on a ratio of weights and determining a message rate for the first vehicle based at least in part on the ratio error and the first parameter value, the message rate describing a speed for transmitting messages from the first vehicle.

9. The system of claim 8, wherein determining the first parameter value for the first vehicle further comprises:

determining a parameter ratio based at least in part on the ratio of weights; and

determining the first parameter value for the first vehicle based at least in part on the parameter ratio.

10. The system of claim 9, wherein the parameter ratio describes a proportion between the first parameter value for the first vehicle and a second parameter value for a second vehicle.

11. The system of claim 9, wherein the parameter ratio equals to the ratio of weights.

12. The system of claim 9, wherein determining of the first parameter value for the first vehicle is further based at least in part on a type of the first vehicle.

13. The system of claim 8, wherein determining the message rate for the first vehicle further comprises determining the message rate for the first vehicle recursively so that the message rate for the first vehicle converges to a steady state message rate based at least in part on the ratio of weights.

14. The system of claim 8, wherein determining the message rate for the first vehicle further comprises:

determining a sign of the ratio error; and

determining the message rate for the first vehicle based at least in part on the sign of the ratio error.

15. A computer program product comprising a non-transitory computer readable medium encoding instructions that, in response to execution by a computing device, cause the computing device to perform operations comprising:

measuring a channel busy ratio describing a fraction of time during which a channel is busy;

calculating a ratio error by comparing the measured channel busy ratio with a target channel busy ratio;

determining a first parameter value for a first vehicle based at least in part on a ratio of weights; and

determining a message rate for the first vehicle based at least in part on the ratio error and the first parameter value, the message rate describing a speed for transmitting messages from the first vehicle.

16. The computer program product of claim 15, wherein determining the first parameter value for the first vehicle further comprises:

determining a parameter ratio based at least in part on the ratio of weights; and

determining the first parameter value for the first vehicle based at least in part on the parameter ratio.

17. The computer program product of claim 16, wherein the parameter ratio describes a proportion between the first parameter value for the first vehicle and a second parameter value for a second vehicle.

18. The computer program product of claim 16, wherein the parameter ratio equals to the ratio of weights.

19. The computer program product of claim 16, wherein determining of the first parameter value for the first vehicle is further based at least in part on a type of the first vehicle.

20. The computer program product of claim 15, wherein determining the message rate for the first vehicle further comprises determining the message rate for the first vehicle recursively so that the message rate for the first vehicle converges to a steady state message rate based at least in part on the ratio of weights.