The rapid increase in vehicle density on roads owing to urbanization and motorization has led to increased risks of roadblocks, traffic jams, and accidents. To ensure the reliability of transportation, it is crucial to have stable and timely transmission of safety messages through Vehicle Ad-hoc Networks (VANETs). However, frequent vehicle movement and changes in the network topology may cause link breakage and packet loss. This paper proposes a solution that uses a fuzzy logic system in both the Medium Access Control (MAC) layer and the network layer to broadcast safety messages efficiently. The proposed rule-based model optimizes the Contention Window (CW) and relay selection process to adapt to different traffic conditions. The dynamic CW MAC (DYCW-MAC) model selects the optimum size of CW based on network parameters such as density, velocity, and link quality factor. For multi-hop communication, the model determines the next forwarding relay by considering factors such as direction, velocity difference, coverage factor, and Fast-Expected Transmission Count (F-ETX) between the sender vehicle and surrounding vehicles within its transmission range. The simulation results indicate that the DYCW-MAC model enhances the network throughput and decreases the average packet delay in comparison to other models.

Summary Safety message dissemination is crucial in vehicular ad hoc networks (VANETs) for road safety applications. Vehicles regularly transmit safety messages to surrounding vehicles to prevent road accidents. However, changing vehicle mobility and density can cause unstable network conditions in VANETs, making it inappropriate to use a fixed contention window (CW) for different network densities. It has been proposed a 1‐D Markov model under unsaturation conditions to analyze the performance of the system with varying CWs under changing vehicle densities. Additionally, it introduces the use of cooperative communication (CoC) to relay failed safety messages. In CoC, two control packets, namely, negative acknowledge (NACK) and enable to cooperate (ETC), are utilized. The proposed analytical model named cooperative communication for safety message dissemination (CoC‐SMD) is used to calculate throughput and average packet delay for varying CW and different packet size. The simulation confirms the validity of the analytical results and show significant improvement in the metrics through the use of varying CW sizes and CoC compared with existing techniques.

Road safety applications provided by the Vehicular ad hoc networks demand less delay, high throughput, and reliable communication under highly dense traffic conditions. It becomes very challenging to design a network that suits the high mobility of vehicles and frequently chang ing network topology. To overcome these challenges in the network, we propose a new algorithm to dynamically adapt the contention window size (DYCW) to the vehicle density conditions. Along with that, we have introduced a cooperative relay vehicle for relaying the safety mes sages that failed to reach the destination. We have also carried out analytical study of the proposed model and the simulation results for the our model show that using DYCW enhances the system functioning by leading to higher throughput with stability in the performance and decreases both the delay and the packet drop ratio (PDR) of the system.

Road safety applications provided by the Vehicular ad hoc networks demand less delay, high throughput, and reliable communication under highly dense traffic conditions. It becomes very challenging to design a network that suits the high mobility of vehicles and frequently changing network topology. To overcome these challenges in the network, we propose a new algorithm to dynamically adapt the contention window size (DYCW) to the vehicle density conditions. Along with that, we have introduced a cooperative relay vehicle for relaying the safety messages that failed to reach the destination. We have also carried out analytical study of the proposed model and the simulation results for the our model show that using DYCW enhances the system functioning by leading to higher throughput with stability in the performance and decreases both the delay and the packet drop ratio (PDR) of the system.

Road safety applications provided by the Vehicular ad hoc networks demand less delay, high throughput, and reliable communication under highly dense traffic conditions. It becomes very challenging to design a network that suits the high mobility of vehicles and frequently changing network topology. To overcome these challenges in the network, we propose a new algorithm to dynamically adapt the contention window size (DYCW) to the vehicle density conditions. Along with that, we have introduced a cooperative relay vehicle for relaying the safety messages that failed to reach the destination. We have also carried out analytical study of the proposed model and the simulation results for the our model show that using DYCW enhances the system functioning by leading to higher throughput with stability in the performance and decreases both the delay and the packet drop ratio (PDR) of the system.