A deterministic MAC protocol for infrastructure to vehicle communications in motorways

The current wireless standards devised for vehicle communications are not designed for hard real-time restrictions. In certain scenarios, such as motorways where a high density of vehicles travelling at high speed is common, the Medium Access Layer (MAC) of the existing standards is not deterministic and does not guarantee an upper bound for the delay of communications. This article discusses several proposals to address this issue and presents a deterministic MAC protocol for infrastructure to vehicle communications: the vehicular flexible time triggered protocol