Conventionally, P2P video is regarded as CBR traffic. However, our measurements have shown that the rate reset cannot be neglected in a practical IPTV system because each rate reset often leads to performance degradat...Conventionally, P2P video is regarded as CBR traffic. However, our measurements have shown that the rate reset cannot be neglected in a practical IPTV system because each rate reset often leads to performance degradation. Thus, addressing the problem of inferring playback rate and rate reset in a P2P video system is significant. In this article, an algorithm termed piecewise linear envelope approximation (PLEA) is proposed, in which a follow-up time is introduced to smooth rate fluctuations in a small time scale and to adapt rate jumps in a large time scale automatically. With the PLEA algorithm, discontinuity introduced by blind segmentations adopted by current methods is avoided. Furthermore, unlike existing algorithms in which both segmentation and combinations are performed in multiple runs, only a single computation path is involved in the PLEA algorithm. This makes PLEA algorithm amenable to implementation of low complexity by either software or hardware. Both theoretical analysis and experiment based on measured data show that the PLEA outperforms existing algorithms based on segmentation.展开更多
随着无线通信发展,无线信道的时变性、有限的带宽及可用功率使得在多用户的无线通信系统中传输高质量的视频成为挑战。自适应速率控制技术能够根据当前的吞吐量情况自适应地调整视频的比特率,可以较好地解决视频播放中断问题。视频播放...随着无线通信发展,无线信道的时变性、有限的带宽及可用功率使得在多用户的无线通信系统中传输高质量的视频成为挑战。自适应速率控制技术能够根据当前的吞吐量情况自适应地调整视频的比特率,可以较好地解决视频播放中断问题。视频播放缓冲区的播放阈值会影响视频播放的上溢或下溢概率,导致视频播放中断或视频跳帧的情况。文中提出了一种LTE网络下考虑Qo E(Quality of Experience)的联合速率控制和缓冲区管理的优化方法 RCBM(Rate Control and Buffer Management)。算法在进行速率控制的同时兼顾播放缓冲区的管理、及时的速率控制和最佳的阈值选择,使得在有限资源的约束和网络状况多变的情况下有效地降低视频播放中断和视频播放跳帧的发生,最大化视频传输服务的Qo E。实验结果表明,并与现有的相关算法比较,RCBM算法能够在有限资源的约束和网络状况多变的情况下有效地降低视频播放中断和视频播放跳帧的发生,从而提升视频的Qo E。展开更多
基金supported by the National Natural Science Foundation of China(60672069,60772043)the National Basic Research Program of China(2007CB307101)
文摘Conventionally, P2P video is regarded as CBR traffic. However, our measurements have shown that the rate reset cannot be neglected in a practical IPTV system because each rate reset often leads to performance degradation. Thus, addressing the problem of inferring playback rate and rate reset in a P2P video system is significant. In this article, an algorithm termed piecewise linear envelope approximation (PLEA) is proposed, in which a follow-up time is introduced to smooth rate fluctuations in a small time scale and to adapt rate jumps in a large time scale automatically. With the PLEA algorithm, discontinuity introduced by blind segmentations adopted by current methods is avoided. Furthermore, unlike existing algorithms in which both segmentation and combinations are performed in multiple runs, only a single computation path is involved in the PLEA algorithm. This makes PLEA algorithm amenable to implementation of low complexity by either software or hardware. Both theoretical analysis and experiment based on measured data show that the PLEA outperforms existing algorithms based on segmentation.
文摘随着无线通信发展,无线信道的时变性、有限的带宽及可用功率使得在多用户的无线通信系统中传输高质量的视频成为挑战。自适应速率控制技术能够根据当前的吞吐量情况自适应地调整视频的比特率,可以较好地解决视频播放中断问题。视频播放缓冲区的播放阈值会影响视频播放的上溢或下溢概率,导致视频播放中断或视频跳帧的情况。文中提出了一种LTE网络下考虑Qo E(Quality of Experience)的联合速率控制和缓冲区管理的优化方法 RCBM(Rate Control and Buffer Management)。算法在进行速率控制的同时兼顾播放缓冲区的管理、及时的速率控制和最佳的阈值选择,使得在有限资源的约束和网络状况多变的情况下有效地降低视频播放中断和视频播放跳帧的发生,最大化视频传输服务的Qo E。实验结果表明,并与现有的相关算法比较,RCBM算法能够在有限资源的约束和网络状况多变的情况下有效地降低视频播放中断和视频播放跳帧的发生,从而提升视频的Qo E。
基金国家高技术研究发展计划(863)(the National High-Tech Research and Development Plan of China under Grant No.2005AA103320) 国家发改委基金项目(the Foundation of National Development and Reform Commission No.科发函字[2005]54 号) 。