Intelligent Transportation Systems (ITS) require Vehicle-to-Everything (V2X) communication. In dense traffic, the communication channel may become congested, impairing the reliability of the ITS safety applications. Therefore, European Telecommunications Standard Institute (ETSI) demands Decentralized Congestion Control (DCC) to control the channel load. Our objective is to investigate whether message-rate or data-rate congestion control provides better application reliability. We compare LIMERIC and PDR-DCC as representatives of the two principles. We analyzed the application reliability of LIMERIC with different data-rates and PDR-DCC with different message-rates for varying traffic densities and application requirements. We observed that, for applications with demanding requirements and in a large variety of vehicular densities, PDR-DCC (data-rate) provides more reliable communication support than LIMERIC (message-rate). Furthermore, the study hints that a combined message-rate and data-rate congestion control can improve reliability further.
- congestion control