Video broadcasting in Vehicular Ad Hoc Networks (VANETs) is beneficial for traffic management, entertainment, and advertising services because video notifications in active safety applications provide more information regarding accident scenarios than simple text messages. However, broadcasting videos over urban VANETs is challenging because of specificities, e.g., dynamic topology, shadowing phenomena, node mobility, and network partition. Moreover, the delay, jitter, and packet loss ratio associated with video streaming should not exceed strict thresholds for an acceptable quality of experience. To meet video streaming requirements, we propose a receiver-based, line-of-sight-aware and reliable bi-directional broadcasting protocol that obtains a tradeoff between broadcast reliability and coverage capabilities. The road network is segmented into a set of straight sections and the bi-directional broadcast method is applied to each section to address the obstructed line of sight problem and the coverage capacity simultaneously. Our protocol selects a sub-set of forwarders likely to have the best line of sight in a fully distributed manner. Furthermore, we overcame packet loss by designing an enhanced version of the store-carry-and-forward method that prioritizes the retransmission of packets containing more important video blocks. The simulation shows that our solution outperforms two innovative video broadcasting protocols in terms of frame loss, peak signal-to-noise ratio, and mean opinion score while keeping the end-to-end delay within the video streaming requirement range.

车载自组织网络 (VANET) 中的视频广播有利于交通管理、娱乐和广告服务，因为主动安全应用中的视频通知比简单的文本消息提供了更多有关事故场景的信息。然而，由于动态拓扑、阴影现象、节点移动性和网络分区等特殊性，在城市 VANET 上广播视频具有挑战性。此外，与视频流相关的延迟、抖动和丢包率不应超过可接受的体验质量的严格阈值。为了满足视频流的要求，我们提出了一种基于接收器、视线感知且可靠的双向广播协议，该协议在广播可靠性和覆盖能力之间取得了平衡。将路网分割成一组直线路段，对每个路段采用双向广播的方法，同时解决视线受阻问题和覆盖容量问题。我们的协议以完全分布式的方式选择可能具有最佳视线的转发器子集。此外，我们通过设计存储携带转发方法的增强版本来克服数据包丢失问题，该方法优先重传包含更重要视频块的数据包。仿真表明，我们的解决方案在帧丢失、峰值信噪比和平均意见得分方面优于两种创新的视频广播协议，同时将端到端延迟保持在视频流要求范围内。