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Special Report
Bradley Fellow/Scholar Alumni

 April 2001




Communications Research

Associated Laboratories, Groups and Centers:
Center for Wireless Telecommunications
Digital Signal Processing and Communications Lab
Mobile and Portable Radio Research Group

Current research in the communications area includes fiber optic communications, mobile and portable radio communications, wireless communications, digital signal processing, wideband networks, and satellite communications.

Fiber optic communications research deals broadly with the interrelationship between system technology, architecture, and application. Principal applications that have been considered include high-speed digital long-distance systems, local and wide area computer networks, television distribution networks, and interfaces between fiber and mobile radio systems. During this past year, research continued on (a) system architecture and technology for wavelength-division-multiplexed systems, (b) analysis and simulation of the combined effects of nonlinearity and dispersion in long distance systems and optimal signal design for such systems, (c) design and analysis of new topologies to achieve highly survivable networks, (d) characterization and mitigation of polarization mode dispersion effects in fiber optic systems, and (e) application of plastic optical fiber in automotive networks. (See Electromagnetics for additional fiber optic research activities.)

Representative Research Projects in Communications

Representative Research Projects in Communications
Fractal Modulating Using Wavelets for Digital Communications Systems
Selective Interference Cancellation Techniques for Enhanced Communications Throughput
NAVCIITI Smart Antennas
Configurable and Robust Wireless Communications Nodes
Low Power and Robust Communications using hand-held Smart Antennas for Receiving and Transmitting
An Investigation of Base Station Delivery for Cellular Applications
Reconfigurable Apertures and Space-Time Processing
Turbine Engine Control using MEMS for Reduction of High Cycle Fatigue
Measurement and Modeling of Broadband Millimeter Wave Channels for Fixed and Mobile Next Generation Internet
Development of Simulation and Design Tools for Wireless Research
A Collaborative Problem Solving Environment for Modeling of Broadband Wireless Communication Systems
Research into Spatial Signal Recovery Algorithms in Support of Spectral Spatial Interference Cancellation System
Research & Development for IMT-2000
Broadband Wireless System Design: Riverstone Park
Geographic-Engineering Tool for Wireless Evaluation of Broadband Systems "GETWEBS"
Wireless Link for Miniaturized Robust Multichannel Telemetry System
Monolithic/MCM Filter Development for Highly-Integrated Digital Radios
Testbed for High-Speed End-To-End Communications in Support of Comprehensive Emergency Management
Web-based Service for the Broadband Wireless Industry
Technical Support for "Connexion by Boeing"

Center for Wireless Telecommunications (CWT)

CWT Affiliated ECE Faculty Members:

Charles Bostian, Director
Louis Beex
Luiz DaSilva
Nathaniel Davis IV
William Davis
Dong Ha
Scott Midkiff
Amitabh Mishra
Tim Pratt
Sanjay Raman
Warren Stutzman
Dennis Sweeney

CWT is a Technology Development Center of Virginia's Center for Innovative Technology (CIT). Its primary goals are to help client companies develop new products and deploy services using wireless technology, and to provide a learning environment that prepares graduate students for jobs in wireless telecommunications. A university interdisciplinary research and development center, CWT includes faculty and students from three colleges (Arts and Sciences, Business, Engineering) and nine departments. CWT promotes the collaboration and interaction among its associated faculty and students so that its graduates understand both the technical and the business aspects of the wireless industry.

Broadly, CWT develops technology and designs and builds hardware and software for all wireless applications. It specializes in proof-of-concept prototypes, which are fully tested and operational pieces of equipment that are ready for production. While CWT supports a wide range of projects, its particular areas of concentration are radio hardware design, software for wireless networking, and spectrum allocation. Long-term research work includes embedded radio systems, advanced broadband wireless Internet access, and radio spectrum auction and allocation strategies. CWT's largest and most recent project has been its work with LMDS (Local Multipoint Distribution Service) network development. LMDS is a new 28 GHz allocation and the first of several broadband services to be deployed worldwide. CWT initiated Virginia Tech's participation in the FCC's 1998 spectrum auction, in which the university purchased spectrum licenses for four basic trading areas.

In 1999, CWT worked with Communications Network Services (CNS), the Virginia Tech Office of Information Systems, and Wavtrace, now Harris Corp. of Bellevue, WA, to deploy a point-to-multipoint network in the Blacksburg area. The network delivers two-way, high-speed data, voice, and video traffic from a hub site on the Virginia Tech campus to three off-campus buildings that did not previously have high-speed connections to the on-campus broadband network.

A current CWT project, funded by the NSF, is called GETWEBS (Geographic-Engineering Tool for Wireless: Evaluation of Broadband Systems). As part of the project, a new course is offered through the departments of Geography, ECE, and Finance, in which advanced undergraduate and graduate students along with faculty are developing a suite of software tools for wireless network system design and layout. This course brings together students and faculty from engineering, business, and the social sciences to evaluate implementation strategies for fourth-generation wireless communications. It will be offered for the second time during Summer, 2001.

CWT has recently worked with the Boeing Company on the policy and regulatory aspects of its plan to offer Internet access to commercial air travelers with Connexion by Boeing™.
CWT researchers are developing a flexible and rapidly deployable "last mile" broadband wireless network based on, but not limited to, LMDS technology. The goal is to provide a communications system that can be moved into a disaster area and quickly integrated with surviving federal, state, and local fiber networks. The wireless network can become a common electronic meeting ground for the disaster relief community.

In January 2001, CWT was selected by the Wireless Telecommunications Association as a WEMMIE award winner. 'Wireless Emmys' were presented to those providing the most advanced technologies and/or the best broadband service to underserved communities, including schools, colleges and remote rural areas.

Digital Signal Processing and Communications Lab (DSPCL)
Amy Bell, Director

The members of the Digital Signal Processing and Communications Lab (DSPCL; pronounced "de-speckle") conduct state-of-the-art research in signal processing and communications.  The specific research interests within DSPCL include: wavelet-based image compression, wavelet modulation, image segmentation, engineering education and fusion-based algorithms for improved geolocation estimates in wireless networks. DSPCL researchers have presented and published their work in the premier international journals and conferences in signal processing and communications. DSPCL's research endeavors have been financially supported by several organizations, among them: the National Science Foundation; Nortel Networks; and, the Alfred P. Sloan Foundation. Former DSPCL students are employed throughout the U.S. and Europe in information technology industries ranging from large, international corporations to small, start-up companies.


Mobile and Portable Radio Research Group (MPRG)

MPRG ECE Faculty
Jeffrey Reed, Director
Theodore S. Rappaport
William H. Tranter
Brian Woerner

Associated ECE Faculty
Lynn Abbott
Annamalai Annamalai
Peter Athanas
Luiz DaSilva
David deWolf
Dong Ha
Ira Jacobs
Pushkin Kachroo
Scott Midkiff
Amitabh Mishra
Sanjay Raman
Hugh VanLandingham


Bill Newhall (G) tests his software radio in the MPRG laboratory. The software-defined measurement receiver simultaneously samples signals from four antenna elements at 1 gigasample per second for each channel. The system is being used for wideband smart antenna experiments and radio channel characterization.



The MPRG provides leading-edge research and state-of-the-art educational opportunities for students in wireless communications. Its research focuses on the creation of wireless systems that will permit ubiquitous and instantaneous access to information throughout our daily lives. The MPRG works to understand the interplay between propagation, receiver design, signal processing, networking and applications. The work has commercial applications in the areas of cellular telephone, personal communications, land mobile radio, wireless data networks, and high-speed data links.

Five core faculty members, 12 associated faculty members, nine staff members, and 40 graduate students work together to provide a national resource for research and education in the field of wireless communications. Since its inception in 1990, MPRG has graduated more than 200 undergraduate and graduate students, who are now employed in positions of leadership in the rapidly expanding wireless communications industry.

MPRG researchers are recognized leaders in the fields of radio wave propagation measurement and prediction, digital signal processing, code division multiple access, software radio, and communications system design and simulation. MPRG's 2000 research budget was more than $2 million. Core support for MPRG is provided through a coalition of 22 industrial affiliate companies. The MPRG also conducts long-term research sponsored by the NSF, DARPA, the Office of Naval Research, and several leading wireless communications companies. The MPRG affiliates program facilitates rapid dissemination of research results to industry. In June 2001, the 11th Symposium on Wireless Personal Communications will attract over 200 working engineers to Virginia Tech for continuing education and exposure to Virginia Tech's wireless expertise.

During the past year, MPRG researchers completed a DARPA-funded software radio project that proved the utility of reconfigurable computing applied to software radio design.  They also developed new array processing techniques designed to reduce the size of cellular antennas, while extending the range and increasing the capacity of emerging 3rd Generation wireless systems. Recent research initiatives include the creation of several test beds for space-time signal processing. Additionally, MPRG is examining WLAN systems and Bluetooth™ technologies and their related interference and deployment issues.


The Bradley Department
of Electrical and Computer Engineering
Virginia Tech

Last Updated, July 15, 2001
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