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

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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.