Weighted-fairness in message rate based congestion control for vehicular systems
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.
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 recursively based at least in part on the ratio error and the first parameter value so that the message rate converges to a steady state message rate based at least in part on the ratio of the weights, 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 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.
7. A system comprising:
one or more processors;
a measurement module executable by the one or more processors to measure a channel busy ratio describing a fraction of time during which a channel is busy;
a calculation module executable by the one or more processors and communicatively coupled to the measurement module, the calculation module executable to calculate a ratio error by comparing the measured channel busy ratio with a target channel busy ratio; and
a determination module executable by the one or more processors and communicatively coupled to the calculation module, the determination module executable to determine a first parameter value for a first vehicle based at least in part on a ratio of weights and to determine a message rate for the first vehicle recursively based at least in part on the ratio error and the first parameter value so that the message rate converges to a steady state message rate based at least in part on the ratio of the weights, the message rate describing a speed for transmitting messages from the first vehicle.
8. The system of claim 7 , 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.
9. The system of claim 8 , 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.
10. The system of claim 8 , wherein the parameter ratio equals to the ratio of weights.
11. The system of claim 8 , 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.
12. The system of claim 7 , 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.
13. 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 recursively based at least in part on the ratio error and the first parameter value so that the message rate converges to a steady state message rate based at least in part on the ratio of the weights, the message rate describing a speed for transmitting messages from the first vehicle.
14. The computer program product of claim 13 , 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.
15. The computer program product of claim 14 , 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.
16. The computer program product of claim 14 , wherein the parameter ratio equals to the ratio of weights.
17. The computer program product of claim 14 , 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.