Cooperative Transmission Aid in Intermittent Broken Connection on VANET

Network quality of VANET (Vehicular Ad-hoc Network) is usually bad due to speed variation, high mobility, driver behavior, traffic density, swarm effect, environment complexity, et al. Speed variation dynamically changes the car-to-car distances frequently and results in broken connections. Besides, VANET´s network topology usually deployed along with the roadside, the nearby car is very probably the best candidate to help with relay packets when a broken connection occurs. On the other hand, each re-establishment of a broken connection will increase transmission time and waste transmission bandwidth. In this paper, we propose a Cookie-Cooperative Automatic Repeat reQuest (CCARQ) mechanism to enhance network performance by repairing intermittent broken connections. CCARQ will be able to assist Network Layer in transmission through MAC layer. Simulations show that CCARQ outperforms both AODV and Bypass-AODV in packet delivery ratio, end to end delay, and goodput.