Abstract—Nowadays, cooperative ITS is the trend and the focus of the world, which can solve traffic safety problems through data dissemination in Vehicular Ad-hoc Networks (VANETs). Messages generated by different applications have different levels of urgency, thus they should have different priorities and Quality of Service (QoS) requirements. At present, most researches simply prioritize messages based on the message type, and set fixed priorities for messages according to the empirical urgency level. The fixed priority setting cannot adapt to the actual dynamic traffic environment. Therefore, according to the urgency level of different applications, we propose a dynamic priority algorithm and a cross-layer priority-mapping method to implement broadcasting messages with different priorities. In order to reflect more accurate priority of messages timely, several aspects are considered, including the current transportation situation, effective range and multi-hop broadcasting. Then the priority is mapped to the MAC layer in reference to the EDCA protocol. Several parameters in MAC layer are adjusted to provide different QoS levels for different messages. The simulations verify the performance of broadcasting messages with different priorities and the advantages of the proposed broadcasting mechanism.

Index Terms—VANETs, cross-layer design, QoS, dynamic priority.

Cite: Nguyen Ngoc Van, “The Cross-layer Message-broadcasting Mechanism for Active Road Safety Application Based on Dynamic Priority,”Journal of Communications vol. 14, no. 11, pp. 1075-1083, 2019. Doi: 10.12720/jcm.14.11.1075-1083