ITR: Cross-Layer Design of Ad-Hoc Wireless Networks for Real-Time Media

ad-hoc无线网络是可能移动的无线节点的集合，这些节点可以在没有任何已建立的基础设施的帮助下进行自我配置以形成网络。对于部署通信基础设施过于昂贵、无法快速部署或根本不可行的应用程序来说，缺乏基础设施是非常引人注目的。这些应用范围从多跳无线宽带互联网接入到传感器网络，从楼宇或高速公路自动化到语音、图像和视频通信应急响应，这是我们社会迫切需要的一种救生能力。自组织无线网络的性质使得支持延迟关键型应用程序（如语音和视频）非常具有挑战性。在这个项目中，研究人员研究了一个新的自组织无线网络设计框架，以支持这种延迟关键应用。该框架包括网络资源的动态分配以支持媒体需求，对网络中的变化和不确定性具有鲁棒性的协议，以及自适应媒体压缩技术，即使在网络条件较差时也能保持端到端网络连接。该项目的成果预计将对未来无线网络的发展和关键应用的实现产生重大影响。为支持自组织无线网络中的延迟关键应用而开发的框架是基于跨网络协议栈的跨层设计。该设计集成了跨多协议层的自适应，包括应用层、传输层、网络层和链路层。在此框架内，研究人员开发了一套新技术，通过共同优化错误弹性源编码、数据包调度、基于流的路由、链路容量分配和自适应链路层技术来平衡网络拥塞和实时媒体流的失真。所有节点基于链路状态通信进行动态优化，以不断适应不断变化的链路和轨迹条件。该研究项目系统地研究了这些新想法，并最终在一个小型测试平台上进行了验证。

ABSTRACT0325639Goldsmith, AndreaStanford UniversityAn ad-hoc wireless network is a collection of possibly mobile wireless nodes that self-configure to form anetwork without the aid of any established infrastructure. The lack of infrastructure is extremely compellingfor applications where a communications infrastructure is too expensive to deploy, cannot be deployedquickly, or is simply not feasible. Such applications range from multi-hop wireless broadband Internetaccess to sensor networks to building or highway automation to voice, image, and video communication foremergency response, a life-saving capability urgently needed by our society. The nature of ad-hoc wirelessnetworks makes support of delay-critical applications such as voice and video quite challenging. In thisproject the investigators study a new framework for ad-hoc wireless network design to support such delay-critical applications. The framework includes dynamic allocation of network resources to support mediarequirements, protocols that are robust to variations and uncertainties in the network, and adaptive mediacompression techniques that preserve end-to-end network connectivity even when network conditions arepoor. The results of the project are expected to have a significant impact on the development of futurewireless networks and the enabling of critical applications.The framework being developed to support delay-critical applications in ad-hoc wireless networks is basedon cross-layer design across the network protocol stack. The design incorporates adaptation across multipleprotocol layers, including the application, transport, network, and link layers. Within this framework, theinvestigators develop a suite of new techniques to balance network congestion and distortion of real-timemedia streams by jointly optimizing error-resilient source coding, packet scheduling, stream-based routing, link capacity assignment, and adaptive link layer techniques. The optimization is carried out dynamically by all nodes, based on link state communication, to continuously adapt to changing link and trac conditions.The research project systematically investigates these new ideas and ultimately demonstrates them in a smalltestbed.