LTE-V2X下的实时视频流传输策略研究

Research on Transmission Strategy for Real‐time Video Stream Under LTE‐V2X

为提高在蜂窝小区内的视频传输质量,增强智能网联汽车的盲区视角感知能力,从而提高驾驶安全性和便利性,本文提出在LTE-V2X下完成实时视频流传输的可靠策略。首先,为提高蜂窝小区的系统性能和实时视频流传输的画面质量,提出在不完美信道状态下,满足V2X用户异构服务质量的同时,最大化V2V通信吞吐量的资源分配算法。该算法采用1阶自回归模型对真实的信道增益进行建模,分步骤进行功率分配和频谱复用配对,以完成资源分配;接着,采用可伸缩视频编码技术对实时视频流进行编码,编码后具有不同的视频质量等级的视频数据帧,经由网络传送,而以网络感知数据为基础,构建视频流缓冲区;最后,设计自适应传输算法求得当前最佳传输视频质量等级,根据通信网络环境动态调整传输视频画面质量,以有效减少视频播放冻结次数。实验结果表明,相比于具有基础层保护的视频传输算法RALSB和视频质量自适应传输算法VQAS,本文所提策略能有效提高实时视频流质量,减小视频播放冻结次数。

In order to enhance the video transmission quality in cellular community,to strengthen the visual a reliable strategy for achieving real-time video stream transmission under the environment of long-term evolution-vehicle to everything(LTE-V2X)is proposed in this paper.First of all,for improving the system performance of cellular community and the image quality of real-time video stream transmission,a resource allocation algorithm is put forward for maximizing vehicle to vehicle communication throughput,while meeting the requirements of heterogeneous service model for the modeling of real information channel gain,and the power distribution and the multiple access and pairing of spectra are carried out step-by-step to complete the resource allocation.Then,scalable video coding technique is used to encode real-time video streams,the encoded video data frames having different video quality level are transmitted via network,and based on the perceived data from network,video stream buffer is set up.Finally,adaptive transmission algorithm is designed to calculate the current optimal quality level of transmitted video,and the quality of video images transmitted can be dynamically adjusted according to the communication network environment,so the chance of video playback freezing is effectively reduced.The results of experiment show that compared with video transmission algoproposed can effectively enhance the quality of real-time video stream and reduce the chance of video playback freezing.