A Fluid Simulation Methodology and Tool for Complex Large Scale Net-works

在这项提案中，我们对超宽带(UWB)无线电中的基本问题进行了全面的研究，包括实验和分析。所提出的工作涉及实验和分析组件之间的强烈交互，因此实验得出的模型可以用于设计优化算法，而优化算法可以反过来进行测试。为此，需要无线电、视频和测试设备来补充超宽带无线电实验室(ULTRA Lab)的现有设施。该设备将用于三个密切相关的研究项目，以支持全移动室内视频通信系统的发展。激励无线技术的是扩频脉冲无线电，它缓解了多径问题，但必须与大约500 MHz到2 GHz频率范围内的信号共存于同一频谱中。这些实验的目的是(1)量化不同无线电系统在同一频段内共存而不相互干扰的能力；(2)量化超宽带天线和传播环境的失真特性；(3)测量室内无线电性能异常对视频传输的影响。所要求的设备包括消声室组件、灵活的软件视频压缩系统、可用于视频和无线电干扰实验的高质量局域网、误码率测试仪以及干扰和共存测试所需的其他组件。这些实验将产生一个频道测量数据库，它描述了传播、天线和干扰影响的特征。该数据库将被用来提取统计模型，这些模型将被用来开发接收机信号处理和视频速率控制的算法。这一实验、模型提取和算法开发过程将在请求支持期间反复进行。这些实验中的每一个都简要描述如下：(1)干扰抑制和共存实验与分析(Scholtz和Chugg)。这项实验工作将探索功率谱从500 MHz到2 GHz的稀疏分布的冲激无线电在短距离信道上与该宽谱内的无数其他电子系统共存的能力。这项工作将测试与局域网、无绳电话、微波炉、无线电视链路等的共存。将检查脉冲无线电中采用的扩频技术的处理增益，并测试当前脉冲无线电的动态范围。这些实验将决定冲激无线电实现的研究方向。(2)超宽带天线和传播环境的特性(Prata，Chugg，Scholtz)。在电波暗室的受控环境中进行的实验工作支持了脉冲无线电超宽带天线的特性，以及窄带天线的特性以评估其接收/拒绝脉冲的能力。这种环境将用于评估新的UWB天线设计，这些设计提供更稳健的空间覆盖、更好的脉冲整形特性和极化分集，并研究UWB信号在不同类型材料中的传播。根据这笔赠款购买的设备将用于在不久的将来建造一个至少15‘(宽)x 15’(H)x 30‘(L)的暗室(包含这个暗室的建筑的建筑工程现在正在开始)。(3)在UWB无线链路上使用软件压缩的异步视频的实验(奥尔特加，楚格)。在稳健的异步视频传输的实验工作中，计划了两个阶段。在第一阶段，将使用笔记本电脑和无线局域网设备来测试技术，这些技术目前正在研究时变信道上的速率控制。所有视频功能(压缩、速率控制、纠错、重传等)将在软件中实现。在第二阶段，算法将被改装成在实验性的脉冲无线电链路上运行。在这一点上，将纳入初始阶段的结果，还将实施针对脉冲无线电特定传输条件所需的更改。申请资助的每一名学生研究人员都将参与所有这三个方面的工作。这项研究将得到UltraLab基础设施的进一步支持，该基础设施最近在NSF的支持下通过集成媒体系统中心ERC和我们的行业赞助商开发。基础设施包括实验室空间、设备、一支协助实验室程序的本科生优秀学者团队，以及从南加州大学合作者和产业合作伙伴那里获得电路和半导体工艺专业知识的途径。本提案中描述的研究是开发和演示UWB室内无线电多媒体系统所需的基础研究的一部分(对集成电路设计的补充研究也是必要的，但不是本文提出的研究的一部分)。这项提议的原始设备预算已经修订，以反映从其他来源购置的设备，目前没有关于这项工作的其他提议待决。

In this proposal a complete study of fundamental issues, both experimentaland analytical, in ultra-wideband (UWB) radio is presented. The proposedwork involves a strong interaction between experimental and analyticalcomponents, so that experimentally derived models can be used to designoptimized algorithms, which can in turn be tested. For this purpose, radio,video, and test equipment is requested to complement existing facilities inthe ultra-wideband radio lab (UltRa Lab). This equipment will be used forthree closely related research projects that support the development offully mobile indoor video communication systems. The motivating wirelesstechnology is spread-spectrum impulse radio, which alleviates multipathproblems, but must coexist in the same spectrum with signals in thefrequency range from roughly 500 MHz to 2 GHz. The experiments are aimed at(1) quantifying the ability of different radio systems to coexist in thesame band without mutually interfering, (2) quantifying the distortionproperties of ultra-wideband antennas and propagation environments, and (3)measuring the effects of indoor radio performance anomalies on videotransmissions. The equipment requested includes anechoic chambercomponents, a flexible software video compression system, high quality LANsthat can be utilized in both the video and radio interference experiments,and a bit error rate tester and other components necessary for interferenceand coexistence tests. These experiments will result in a database ofchannel measurements which characterize propagation, antenna, andinterference effects. The database will be used to extract statisticalmodels which, in turn, will be used to develop algorithms for receiversignal processing and video rate control. This process of experimentation,model extraction, and algorithm development will be iterated throughout theduration of the requested support. Each of these experiments is brieflydescribed below.(1) Interference Rejection and Coexistence Experiments and Analysis(Scholtz and Chugg). This experimental work will explore the ability ofimpulse radio with power spectrum thinly spread roughly from 500 MHz to 2GHz to coexist over short range channels with the myriad of other electronicsystems in that broad spectrum. This effort will test coexistence withLANs, cordless phones, microwave ovens, wireless TV links, etc. Theprocessing gain of the spread spectrum techniques employed in the impulseradio will be checked and the dynamic range of current impulse radios willbe tested. These experiments will determine the direction of researchefforts on impulse radio implementation.(2) Characterization of ultra-wideband antennas and propagationenvironment (Prata, Chugg, Scholtz). The experimental work to be carriedout in the controlled environment of an anechoic chamber supports thecharacterization of ultra-wideband antennas for impulse radio, and thecharacterization of narrower-band antennas to evaluate their ability toreceive/reject impulses. This environment will be used to evaluate new UWBantenna designs that provide more robust spatial coverage, better pulseshaping characteristics, polarization diversity, and to study thepropagation of UWB signals through different kinds of materials. Theequipment purchased under this grant is destined for an anechoic chamber atleast 15' (w) x 15' (h) x 30' (l) to be constructed in the near future(architectural work on the building containing this chamber is beginningnow).(3) Experiments with Software-Compressed Asynchronous Video over UWBWireless Links (Ortega, Chugg). Two stages are planned in the experimentalwork with robust asynchronous video transmission. In a first stage, laptopsand wireless LAN equipment will be used to test techniques, which arecurrently under study for rate control over a time varying channel. Allvideo functions (compression, rate control, error correction,retransmission, etc.) will be implemented in software. In a second stagethe algorithms will be adapted to operate over an experimental impulse radiolink. At that point the results from the initial stage will be incorporatedand also changes needed for the particular transmission conditions ofimpulse radio will be implemented.Each of the student researchers supported under the requested funding willbe involved in all three of these aspects. This research will be furthersupported by the UltRa Lab infrastructure, which has been developed recentlyunder the support of NSF and through the Integrated Media System Center ERCand our industrial sponsors. The infrastructure includes laboratory space,equipment, a team of undergraduate merit scholars to assist in laboratoryprocedures, and access to circuit and semiconductor process expertise fromboth USC collaborators and industrial partners. The research described inthis proposal is a portion of the fundamental investigations required todevelop and demonstrate UWB indoor radio multimedia systems (complementaryinvestigations into integrated circuit design are also necessary, but arenot part of the research proposed herein). The original equipment budget forthis proposal has been revised to reflect equipment acquisitions from othersources and no other proposals for this work are currently pending.