ITR: Collaborative Research: Optimization and Integrated Control of Low Power Wireless Multimedia Networks

ITR：协作研究：低功耗无线多媒体网络的优化和集成控制

• 批准号: 0082064
• 负责人: Mary Irwin
• 金额: $ 49.86万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2004-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0082064&HistoricalAwards=false
• 关键词: ITR; Collaborative; Research; Optimization; Integrated

Recent years have seen an explosive growth in the number of multimedia devices and communication tech-nologies. While these multimedia technologies still depend on wireline links, the future of multimedia com-munication is in wireless. Mobile multimedia networks will provide seamless communication between roam-ing users. Applications such as video conferencing or internet access will become available from any where in the world. Widely varying classes of network traffic (traffic heterogeneity) that change over time will be generated by multimedia applications. The network itself will consist of both wireline and wireless links (network heterogeneity). We are already beginning to feel this change.A major constraint in multimedia wireless technology is the limited power budget. Mobile devices such as laptops and personal digital assistants have limited battery life. The re-chargeable battery technology has resulted only in a small increase in battery efficiency. So, it is important to optimize network protocols for minimum power to ensure the continued growth of wireless based multimedia communication. Many attempts have been made towards this goal at individual layers of the network protocol stack. Most of these efforts have concentrated only at the physical and link layers. In this proposal, we deal with the wireless network protocol stack as a whole and provide a unified framework to optimize both computation and transmission power at various layers of the protocol stack. A power manager serves as the central core of our framework. Thedifferent layers of the protocol stack communicate with each other through the power manager that makes adaptive policy decisions based on the network, traffic, and power limitations. This is a uniqueness of the proposal. In the conventional model, the network layers have minimal or no communication at all leading to poor performance compared to the proposed framework. The proposed methods strive to optimize the quality of service (QoS) with minimum power consumption at the mobile wireless nodes. Towards achieving our objectives we consider the following research issues :Adaptive source coding and modulation strategies at the physical layer that minimize power for a desired reliability. The adaptation is done based on channel state estimates produced by the link layer.New error-resilient coding methods that do not have the drawbacks of the conventional forward error correcting codes. Little overhead, graceful degradation, and simple encoding and decoding that reduce the power requirements for computations are the main strengths of the coder. The coders are especially well-suited for state-of-the-art compression standards like JPEG, MPEG, and H.263. Radically different on-line channel state estimators are also proposed.Power-aware transport control protocols that distinguish between various channel and battery state.Application layer adaptation mechanisms to conserve power. The mechanisms use techniques from networking and signal processing areas to improve the performance.Adaptive power manager (integrated controller) policies that control the entire wireless network from a global point of view. Reliability, bandwidth, robustness and power considerations are taken into account for policy decisions.A simulation framework to experiment with different hardware configurations and network topologies and constraints. The developed framework will be help to validate and update our theories. This tool that will be made available through the web will be invaluable for other researchers in designing future energy-efficient wireless multimedia systems.

近年来，多媒体设备和通信技术的数量呈爆炸式增长。 虽然这些多媒体技术仍然依赖于有线链路，但多媒体通信的未来是无线的。移动的多媒体网络将提供漫游用户之间的无缝通信。视频会议或互联网接入等应用程序将在世界任何地方都可用。多媒体应用程序将产生随时间变化的各种网络流量（流量异质性）。网络本身将包括有线和无线链路（网络异构性）。我们已经开始感受到这种变化。多媒体无线技术的一个主要限制是有限的功率预算。诸如膝上型计算机和个人数字助理之类的移动的设备具有有限的电池寿命。可再充电电池技术仅导致电池效率的小幅提高。因此，为了保证无线多媒体通信的持续发展，优化网络协议以实现最小功耗就显得尤为重要。已经在网络协议栈的各个层上朝着这个目标进行了许多尝试。这些努力大多只集中在物理层和链路层。在这个建议中，我们处理的无线网络协议栈作为一个整体，并提供了一个统一的框架，以优化计算和传输功率在各个层的协议栈。电源管理器是我们框架的核心。协议栈的不同层通过电源管理器相互通信，电源管理器根据网络、流量和功率限制做出自适应策略决策。这是提案的独特之处。在传统的模型中，网络层具有最小的通信或根本没有通信，导致与所提出的框架相比性能较差。所提出的方法力求优化服务质量（QoS），在移动的无线节点的功耗最小。 为了实现我们的目标，我们考虑以下研究问题：物理层的自适应信源编码和调制策略，以最大限度地减少功耗以获得所需的可靠性。自适应是根据链路层产生的信道状态估计来完成的。新的差错恢复编码方法不具有传统前向纠错码的缺点。小开销、适度降级和简单的编码和解码（降低计算的功率要求）是编码器的主要优势。这些编码器特别适合JPEG、MPEG和H.263等最先进的压缩标准。还提出了完全不同的在线信道状态估计器。区分各种信道和电池状态的功率感知传输控制协议。应用层自适应机制以节省功率。这些机制使用网络和信号处理领域的技术来提高性能。自适应电源管理器（集成控制器）策略，从全局角度控制整个无线网络。策略决策考虑了可靠性、带宽、鲁棒性和功耗等因素。一个仿真框架可以在不同的硬件配置、网络拓扑和约束条件下进行实验。该框架的建立将有助于验证和更新我们的理论。这个工具，将通过网络提供将是非常宝贵的其他研究人员在设计未来的节能无线多媒体系统。