A QoS-Aware Congestion Control Scheme for C-V2X Safety Communications

In vehicle-to-vehicle (V2V) communication, vehicles must periodically broadcast their kinematics information to reduce the chances of collision. When the communication channel utilization becomes high, however, congestion control for the periodic broadcast traffic is inevitable. So far, all standard or proposed congestion control schemes for V2X safety communication have been quality of service (QoS)-blind. Which aspect of the QoS is compromised by a given congestion control scheme has been purely the artefact of the mechanism(s) employed by the scheme, detached from the needs of the safety application running at the time. This paper demonstrates the feasibility of congestion control that allows V2X safety applications to choose a QoS class that preferentially protects the QoS aspect that is more prized for their requirement. And yet, it shows that such congestion control scheme can be engineered to reduce the channel utilization in a uniform manner as before, regardless of the individual choices made by each V2X application.