Microscopic experimental evaluation of multi-hop video streaming protocol in vehicular networks

Most routing protocols in vehicular networks are geared toward supporting safety applications. In this paper, we shift our attention to study if short-range communication (DSRC or WiFi) could also support real-time video streaming applications for moving vehicles. Rendering real-time video streaming in vehicular network is a challenging task, since video streaming applications tend to have stringent Quality-of-Service (QoS) requirements while vehicle-level mobility and severe outdoor fading channel significantly affect route stability. We present a Quality-of-Service routing framework called multi-Criteria Ad hoc Real-time Streaming (CARS). This framework not only provides a multi-hop route that satisfies the stringent QoS requirements imposed by multimedia applications, but also is flexible enough to support a variety of applications with different types of QoS requirements. Moreover, our proposed routing framework accurately monitors network conditions and switches to a better route as the quality of the ongoing route significantly degrades. We further implement our CARS protocol into a small fleet of research vehicles and experiment the implemented protocol in realistic driving scenarios. We learn valuable lessons through empirical experiments and our first-hand experience helps develop a number of optimization policies to further improve performance.