An adaptive TDMA scheduling strategy based on beacon messages for vehicular ad-hoc network

Aiming at dynamic changes of network topology, high real-time security services and high network load in VANETs, this paper proposes an adaptive TDMA slot allocation strategy based on beacon messages (BMA strategy). BMA strategy makes full use of neighbor nodes' beacon messages, including vehicular direction, position, velocity, etc. Meanwhile, each vehicle establishes neighbor table containing beacon messages. By using time slot acquisition algorithm, neighbor table update algorithm and BMA slot allocation strategy, the related model is established. BMA strategy can predict time slot allocation of next frame according to node density ratio. Furthermore, vehicles with similar velocity could acquire near slots, this mechanism reduces the rate of merge collisions. Comparing with ADHOC and VeMAC protocols, BMA strategy has higher time slot competition success rate, less node collision and better scalability.