A new cooperative communication algorithm for improving connectivity in the event of network failure in VANETs.

Communication in Vehicular Ad-Hoc Networks (VANETs) is frequently disrupted by high mobility of nodes, obstacles, and interference-prone links. The communication link between nodes can be maintained using cooperative communication techniques where nodes collaborate with one another to increase the network performance. Implementation of cooperative communication, which requires helpful nodes to collaborate with others, is a difficult task in VANETs due to their inherent characteristics. Selection of a cooperative node which will help during the retransmission process is the most crucial work in the cooperative communication process considering the dynamic nature of nodes. In this study, we formulate a game-theoretic relay selection protocol for MAC-level retransmission, where every node plans to maximize their received incentives, which is determined by an incentive function. Therefore, cooperative neighboring nodes form tree structures to the destination node from transmitter node by using the proposed algorithm, NGOMA. The distributed incentive function stores promiscuous packets in nodes and forms a tree architecture with cooperative nodes to relay messages to the recipient node from the source node in times of packet-loss events. The network formed by the NGOMA protocol by the source and destination node with relay nodes, converges into a Nash network. Numerical results show that NGOMA, which allows nodes to cooperatively store and transmit lost packets to the recipients, reduces the MAC-level retransmission delay by 63% compared to a non-cooperative function, which does not cooperatively relay messages.