Explicit rate based transmission control in vehicle to infrastructure communications

Vehicle to infrastructure communications can provide mobile users with a series of Internet services, such as video streaming, digital map downloading, database access, online gaming, and even safety services like accident alarm, traffic condition broadcast, etc., through fixed roadside units. However, the dynamics of communication environment and frequent changing topology critically challenge the design of an efficient transport layer protocol, which makes it difficult to guarantee diverse quality of service (QoS) requirements for various applications. In this paper, we present a novel transport scheme in infrastructure based vehicular networks, and aim to resolve some challenging issues such as source transfer rate adjustment, congestion avoidance, and fairness in end to end data communications. By precisely detecting packet losses and identifying various causes of these losses (for example, link disconnection, channel error, packet collision, buffer overflow), the proposed scheme adopts different reacting mechanisms to each of the losses. Moreover, it timely monitors the buffer size of the bottleneck RSU, and dynamically makes transfer rate feedbacks to the source nodes to avoids buffer overflow or vacancy. Finally, simulation results show that the scheme not only successfully reduces packet losses due to buffer overflow and link disconnection but also improves the utilization efficiency of channel resource.