Regarding the advantages of video for communications, it is expected that video transmission becomes an inseparable part of most IoT solutions which raises numerous challenges especially over LLNs (Low Power Lossy Networks). Considering these challenges and video transmission requirements for IoT applications, utilizing a proper application layer protocol plays an important role consequently. In this paper, a new application layer protocol for IoT video transmission scenarios, named VE-CoAP is proposed. VE-CoAP, which is an extended version of CoAP, develops complementary methods for improving CoAP performance and overcoming its challenges for video transmission scenarios especially over IoT and LLNs. These methods include pushing data from server to client, supporting parallel flows for data transmission as well as preserving video quality with a combination of guaranteed and best-effort transmission and also a ULP (Unequal Loss Protection) method for prioritizing data partitioned H.264 video sequence. To compare the performance of VE-CoAP to CoAP and HTTP, an evaluation considering metrics such as PSNR, SSIM and video delivery duration is performed. The evaluation shows that VE-CoAP outperforms its rivals for burst data transmission in both lossy or low loss networks and it also preserves video quality at a superior level compared to other protocols over LLNs.

关于用于通信的视频的优势，预计视频传输将成为大多数物联网解决方案不可分割的一部分，这尤其在LLN（低功耗有损网络）方面提出了许多挑战。考虑到这些挑战和物联网应用的视频传输要求，因此，使用适当的应用层协议将发挥重要作用。本文针对物联网视频传输场景提出了一种新的应用层协议VE-CoAP。VE-CoAP是CoAP的扩展版本，它开发了补充方法来改善CoAP性能并克服其在视频传输场景中的挑战，尤其是在IoT和LLN上。这些方法包括将数据从服务器推送到客户端，支持并行流进行数据传输，并通过保证和尽力而为的传输相结合来保持视频质量，还提供了一种ULP（不等损保护）方法来对数据分区的H.264视频序列进行优先级排序。为了将VE-CoAP与CoAP和HTTP的性能进行比较，执行了一项评估，该评估考虑了PSNR，SSIM和视频传递持续时间等指标。评估表明，VE-CoAP在有损或低损网络中的突发数据传输方面均优于竞争对手，并且与其他协议相比，在LLN上，其视频质量也保持较高水平。进行考虑诸如PSNR，SSIM和视频传递持续时间等指标的评估。评估表明，VE-CoAP在有损或低损网络中的突发数据传输方面均优于竞争对手，并且与其他协议相比，在LLN上，其视频质量也保持较高水平。进行考虑诸如PSNR，SSIM和视频传递持续时间等指标的评估。评估显示，VE-CoAP在有损或低损耗网络中的突发数据传输方面都优于竞争对手，并且与其他协议相比，VE-CoAP可以将视频质量保持在更高水平。