Cooperative vehicular networks have yielded remarkable research results to enable the Intelligent Transportation System (ITS) for safe, reliable, convenient, and comfortable driving experience. However, high vehicular mobility, intermittent communication, and frequent network fragmentation hinder the reliable and successful data communication in cooperative vehicular networks. In this paper, we hover the existing group data communication strategies, their common aim is to deliver data to vehicles within a specific group. As the transmission bandwidth is restricted in wireless environments of Vehicular Ad-hoc NETworks (VANET) same as all mobile wireless networks, group data communication is critical for an efficient usage of network resources. To this end, many solutions have been proposed for VANET. In this paper, we briefly summarize the different group data communication in VANET with a detailed synthesis and comparison of all discussed protocols. Furthermore, we classify group-VANET communication into: (i) routing strategy-based and (ii) Quality of Service (QoS)-awareness communication. Moreover, the performance of all protocols is analyzed by comparing their security parameters. Finally, open challenges and future research directions are discussed.

协同车联网已经取得了显着的研究成果，使智能交通系统（ITS）能够提供安全、可靠、便捷、舒适的驾驶体验。然而，高车辆移动性、间歇性通信和频繁的网络碎片阻碍了协作车辆网络中可靠和成功的数据通信。在本文中，我们悬停了现有的组数据通信策略，它们的共同目标是向特定组内的车辆传递数据。由于与所有移动无线网络一样，车载自组织网络（VANET）的无线环境中传输带宽受到限制，因此群组数据通信对于网络资源的有效使用至关重要。为此，已经为 VANET 提出了许多解决方案。在本文中，我们简要总结了 VANET 中的不同组数据通信，并对所有讨论的协议进行了详细的综合和比较。此外，我们将组-VANET 通信分为：（i）基于路由策略和（ii）服务质量（QoS）感知通信。此外，通过比较它们的安全参数来分析所有协议的性能。最后，讨论了开放的挑战和未来的研究方向。