面向异构无线网移动视频传输的联合信源信道编码方式

A Novel Joint Source-Channel Coding Scheme for Mobile Video Delivery in Heterogeneous Wireless Networks

文中针对异构无线网环境下端到端移动视频传输问题,提出一种新的联合信源信道编码方式DRAJSCC.现有的联合信源信道编码(JSCC)方式的主要问题是将服务器与客户端之间的网络视为单一的传输链路.在异构无线网环境下该问题更为复杂,因为通信终端之间存在多个可用的无线接入网络,如果在并发传输过程中选择不可靠的传输链路会严重降低视频质量.为了解决上述问题,文中提出一种基于动态速率分配(Dynamic Rate Assignment)的联合信源信道编码方式(DRA-JSCC),该方法包含3个主要步骤:(1)根据视频应用可容忍的传输丢失率调整前向纠错编码的冗余度;(2)基于端到端传输的延迟上限调整视频编码速率;(3)进行动态视频流多路径分配使端到端的视频失真最小化.文中构建了JSCC方法在多个无线链路并发传输场景的端到端视频失真优化问题,并且对视频信源以及信道失真进行了综合分析.在仿真平台Exata上使用H.264实时视频流进行的实验表明,DRA-JSCC相对于现有方法能有效提高视频峰值信噪比(Peak Signal-to-Noise Ratio,PSNR)以及降低端到端延迟.

To effectively deliver mobile video streaming in heterogeneous wireless networks, we propose a novel Dynamic Rate Assignment based Joint Source Channel Coding （DRA-JSCC） scheme. The existing JSCC schemes generally consider the communication network between end devices as a single transport link. Challenges arise in the context of multiple available links because involving an unreliable wireless network in the transmission will only degrade the video quality. The proposed DRA-JSCC addresses the challenging problem with following steps： （1） FEC redundancy estimation under the loss requirement; （2） source rate adaption within the delay constraint, and （3） dynamic rate assignment for minimizing the end-to-end video distortion. We analytically formulate the JSCC for optimizing video quality over multiple wireless channels and provide comprehensive analysis for the channel distortion. The performance of DRA-JSCC is evaluated through emulations in Exata. Experimental results show that DRA-JSCC outperforms the competing models in terms of video PSNR （Peak Signal-to-Noise Ratio） and end-to-end delay.