Efficient Integration and QoS Management of Video over Wireless Networks

无线网络视频的高效集成和 QoS 管理

• 批准号: 0087761
• 负责人: Wu-chi Feng
• 金额: $ 30万
• 依托单位: Oregon Health & Science University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-15 至 2005-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0087761&HistoricalAwards=false
• 关键词: Efficient; Integration; QoS; Management; Video

We are currently witnessing an incredible transformation in the way we access information andcomputing power. With small handheld devices such as personal digital assistants, cellular phones,and palmtop computers, users are taking their computers with them more often than not. Fur-thermore, with the developments in wireless technologies, users are beginning to slowly move awayfrom their dependence on wired access to their information. While this trend is building significantmomentum, the types of information that are accessed through these devices is still severely lim-ited by the wireless media. Given the bottle-necks associated with today's power-limited portabledevices, the limitation due to channel conditions has not yet been felt by the user; however thestrain on the underlying wireless network will only get worse. The goal of the proposed research is the construction of high performance algorithms for tetherlessaccess which consider overall system goals through joint optimization across multiple layers. Theobjective will be to solve problems which connect the physical layer to the application layer. In thepast, a classical approach to wireless communication system design was undertaken { a modularapproach loosely based on the Open Systems Interconnection reference stack model. For wiredcommunication networks, such a separation of activities led to functioning systems offering solidperformance. However, the deleterious effects of the wireless communications channel force theinvestigation of all possible methods to improve performance. Thus, to provide the desired fidelityand to transport high-data rate information over the wireless medium, joint optimization acrossmultiple communication layers will be necessary. To focus the research, wireless transport of videovia Direct Sequence Code-Division Multiple-Access (DS-CDMA) will be considered. In this project, we propose the research and development of video streaming algorithms that aremore suited for wireless transmission using DS-CDMA as an access methodology. There are severalreasons why this project is necessary. First, current research onmulti-rate detection and estimationalgorithms at the physical layer are not tailored for specific application layer data. Second, many ofthe video transmission schemes over wireless networks have assumed fixed bit-error rates that areintroduced by the wireless transmission. In CDMA systems, the bit-error rate is highly dependenton the channel and the number of active users, both of these processes are time-varying; however,this variability in bit-error rates has not been fully addressed at the application layer. Third, theelasticity ofvideo can be exploited to design efficient algorithms which can take advantage of theshape of video streams as well as time-varying channel conditions to offer desired quality-of-service. This research project has three principle goals:Investigation of efficient multi-rate detection and estimation algorithms for wireless physicalmedia transmission.Investigation of video streaming techniques for wireless networks that use underlying networkcondition feedback to dynamically adjust the forward error correction used to protect thevideo data.Investigation of the integration of physical layer media characteristics and higher-level videoapplications to provide the highest quality-of- service to applications.

我们目前正在目睹一场令人难以置信的变革，在我们获取信息和计算能力的方式上。对于诸如个人数字助理、蜂窝电话和掌上电脑之类的小型手持设备，用户通常会随身携带他们的计算机。此外，随着无线技术的发展，用户开始慢慢摆脱对有线访问信息的依赖。虽然这一趋势正在形成巨大的势头，但通过这些设备访问的信息类型仍然受到无线媒体的严重限制。考虑到与当今功率受限的便携式设备相关联的瓶颈，用户尚未感受到由于信道条件引起的限制;然而，底层无线网络上的压力只会变得更糟。 建议的研究的目标是建设高性能的算法，考虑整体系统的目标，通过跨多个层的联合优化的tetherlessaccess。目标是解决物理层和应用层之间的连接问题.在过去，无线通信系统设计采用了一种经典的方法（松散地基于开放系统互连参考堆栈模型的模块化方法）。对于有线通信网络来说，这种活动的分离导致了提供可靠性能的功能系统。然而，无线通信信道的不利影响迫使人们研究各种可能的方法来提高性能。因此，为了提供所需的带宽并在无线介质上传输高数据速率信息，跨多个通信层的联合优化将是必要的。为了集中研究，无线传输视频通过直接序列码分多址（DS-CDMA）将被考虑。 在这个项目中，我们提出了研究和开发更适合于无线传输的视频流算法，使用DS-CDMA作为接入方法。有几个原因为什么这个项目是必要的。首先，目前物理层多速率检测和估计算法的研究并不是针对特定的应用层数据量身定制的.第二，许多无线网络上的视频传输方案都假设了无线传输所引入的固定误码率。在CDMA系统中，误码率高度依赖于信道和活动用户的数量，这两个过程都是时变的;然而，这种误码率的变化在应用层还没有得到充分的解决。第三，可以利用视频的弹性来设计有效的算法，这些算法可以利用视频流的形状以及随时间变化的信道条件来提供期望的服务质量。 本研究计划有三个主要目标：研究无线物理媒体传输的有效多速率检测和估计算法;研究无线网络的视频流技术，该技术使用底层网络条件反馈来动态调整用于保护视频数据的前向纠错;研究物理层媒体特性和更高级别视频应用的集成，以提供最高的服务质量。