QoS-Aware Video Transmission Over Hybrid Wireless Network for Connected Vehicles

Communication between vehicles enables a wide array of applications and services ranging from road safety to traffic management and infotainment. Each application places distinct quality of service (QoS) constraints on the exchange of information. The required performance of the supported services differs considerably in terms of bandwidth, latency, and communication reliability. For example, high-bandwidth applications, such as video streaming, require highly reliable communication. However, the attenuation of the IEEE 802.11p/DSRC communication link, due to static and mobile obstructing objects, degrades the link quality and can compromise the QoS requirements of the supported applications. On the other hand, a dual-interface hybrid architecture may have a failover or backup mechanism and benefit from more reliable alternatives, such as cellular networks for occasionally offloading data transmission by radio access technology (RAT) selection and vertical handover process. Since 4G/Long-Term Evolution (LTE) is generally not free, it is, therefore, highly desirable to minimize the time during which the cellular interface is used and to return to the IEEE 802.11p/DSRC interface. This paper proposes a hybrid communication approach based on 4G/LTE and the IEEE 802.11p technologies to support a V2X video streaming application. The proposed approach includes details on the underlying communication architecture, a procedure for selecting the best RAT, a real test platform complemented by a standard software protocol stack, and finally an extensive performance evaluation of the proposed solution based on field test measurements. The results indicate that the proposed approach significantly improves the overall reliability of communication with respect to packet and frame delivery metrics.