一种多路传输可伸缩视频流的分组调度算法

A Packet Scheduling Algorithm for Multihomed Scalable Video Streaming

由于无线网络带宽不足,不能满足高质量视频的传输要求,终端用户往往会遭受频繁的播放中断。为了解决上述问题,一种可能的办法是利用终端的多模特性并发地多路传输视频流。多路传输视频流的关键技术之一是分组调度算法,即将视频分组分配到适合的接口进行传输。本文研究了一种多路传输可伸缩编码视频流下基于质量驱动的分组调度算法。为了最大限度地提升接收端的视频质量,该分组调度算法考虑了接入网络的特性以及视频帧的特征。在本文中,视频数据包调度的问题建模为一个受限多重背包问题,而这个问题是已知为NP-hard的。然后,提出了一种分组调度算法,将视频分组调度到合适的接入网进行传输。在NS-2仿真软件中使用真实的视频trace文件去验证该算法利用多模终端传输可伸缩编码视频的性能。仿真结果表明,分组调度算法在PSNR上优于速率控制算法和传统的round-robin算法。

High- quality video delivery in wireless network often suffers from playback interruption due to the limited bandwidth resources. One potential solution is to utilize multiple interfaces of smartphone to transmit video via multi - homing service. To perform multi - homing video transmission, the packet scheduling algorithm should be used to choose which packet should be allocated to which wireless interface. In this paper, a quality - driven streaming algorithm for transmitting scalable video from a remote server to a multi- homed terminal via heterogeneous wireless access networks simultaneously is studied. With the objective to maximize the received video quality at the receiver, the access network conditions and the video frame characteristics are exploited for packet scheduling. The pack- et scheduling algorithm is performed on the unit of Group of Pictures （GoP） and we formulate the packet scheduling problem as a restricted multiple knapsacks problem which is known to be NP - hard. Then we develop a heuristic algorithm to choose the wireless access networks for transmitting the video packets in every time slot. We also evaluate the performance of the proposed algorithm for multihomed scalable video streaming using real video traces in NS - 2. The simulation results demonstrate that our proposed heuristic algorithm outperforms the rate control algorithm and round - robin algorithm in term of PSNR.