Centralized TDMA MAC for Advanced ITS Applications

Currently, the vehicular communications are used for advanced vehicle safety applications like cooperative intersection safety. These applications need high reliability and predictable delay in vehicular communications. The CSMA (Carrier Sense Multiple Access) mechanism is not suitable for advanced vehicle safety applications because the communication delay and communication failure rate increase exponentially with the number of communication devices. In addition, CSMA causes unfairness between users as the network load increase. In this paper, the authors propose the Centralized TDMA (Time Division Multiple Access) MAC (Medium Access Control) protocol which has a central controller assigning time slots for the reliability and fairness. In addition, the authors present the implementation by the software and show the test result of the average delay.