Electrical and Computer Engineering
"Massive wireless connectivity can be deployed faster and cheaper than wire alternatives. This will enable more people to use the services."
- Fernando Morales,
"The IRS project is one of our best examples of how a company, CIT, Virginia manufacturers, and the University can work together on a project that combines economic development with important research issues."
New Wave Wireless Services
Department researchers are developing technology for wireless local loop, wireless interactive television, data services and home/personal security systems.
The recent FCC auction of frequency spectra for wireless personal communications services provided a shot of adrenaline to an already vigorous industry. Wireless personal communications systems will involve a range of services from telephone, Internet and data services to interactive television - and even home and personal security systems.
"The demand for wireless systems is so great that by 2020, half of the information sent anywhere in the world will involve wireless communications," said Ted Rappaport, founder of the Department's Mobile and Portable Radio Research Group (MPRG).
Predictions are that the development and deployment of these services will require about $2 for every dollar of the $8 billion spent at auction. Similar to the personal computer industry in the early 1980s, the wireless communications market is expected to involve the large, established communications companies and thousands of small development firms and suppliers. Many of these communications firms are in Virginia.
Through the University's Center for Wireless Telecommunications (CWT) and MPRG, Virginia Tech researchers are involved with Virginia firms and companies across the country on wireless communications projects.
Accessibility and Low Cost
The convenience of use and low cost compared to wired systems are behind the demand for wireless systems. One project under development by MPRG researchers involves a wireless stationary telephone system for use in developing countries and remote areas that do not have an installed base of copper wire. Called a Wireless Local Loop (WLL), the system can provide both high quality voice and data communications to users at fixed locations. "By restricting user mobility, WLL systems can avoid many of the infrastructure costs associated with cellular systems," said Brian Woerner, MPRG director.
Convenience and Flexibility
One start-up firm in Herndon, Virginia, is working with Tech researchers to develop a one-way wireless network that would offer multiple services. The Interactive Return Service, Inc. network could eventually include mobile and high-speed, home-based Internet access, interactive television, wireless home shopping, and wireless monitoring services.
Users would purchase a $29 Audio-Link device, which resembles a hand-held television remote control unit. The Audio-Link device would be capable of sending wireless signals to a central station. With interactive television, for example, a digital code would be inserted into commercials and TV programs. Viewers would press a button on the Audio-Link device when they want to purchase or get more information on an item featured on TV. The device would then transmit a signal that includes the viewers' account numbers, along with the commercial code, to local cellular sites. The cellular sites would relay the information to a host system, which would decode the information and send it to the advertisers, who would send the product or information to the viewers and bill them.
The system would work in a similar mode for monitoring services and panic buttons. Smoke or burglar alarms on the network would automatically and wirelessly send a signal for help. The wireless link could not be easily disrupted, making it more reliable than conventional wired systems.
The Audio-Link system is the brainchild of Fernando Morales, chief executive officer of Interactive Return Service, Inc., who envisions a nationwide network of repeater stations that would transmit signals from homes to local cellular sites, and on to host systems.
Morales projects an annual potential market of $3.8 billion for integrated wireless services. "Users will find them to be easy-to-use, convenient, and reliable," he said.
"The network will also be a boon to advertisers, television networks, and rescue agencies," he said. "Massive wireless connectivity can be deployed faster and cheaper than wire alternatives. This will enable more people to use the services." The cost savings stem from the use of the 900 MHz spectrum, which does not involve licensing costs, and the use of existing cellular infrastructure.
When Morales needed research and development help, he turned to Virginia's Center for Innovative Technology (CIT), and through it to the University's Center for Wireless Telecommunications (CWT), directed by Professor Charles Bostian.
Virginia Tech researchers are designing and building prototypes of the hand-held transmitter, and the repeater stations, along with developing the coding, control and networking techniques. A small, efficient antenna for transmitting has been developed for use on the hand-held unit, along with a receiving antenna for the relay station. A cost-effective wireless web browser is under development, and a communications network has been designed for the cellular architecture.
"The research and development issues of this project are diverse and fascinating," commented Willard Farley, CWT's assistant director. "We have teams in DSP, controls, networks, RF, human factors, and antennas." Tech's effort involves four laboratories, five faculty members, three research associates, 14 graduate students and several undergraduates.
The earliest research for the project involved work by the Department's Digital Signal Processing Research Laboratory inserting digital codes into television commercials. "The challenge was finding a way to hide the digital code within the commercials' audio so that the Audio-Link device could detect it and humans wouldn't hear it," said John Tilki (G), who worked on the problem. "Working in the psycho-acoustic area is fascinating. Human perception of an audio signal is dependent on the signal's duration, frequency content and power level."
"The IRS project is one of our best examples of how a company, CIT, Virginia manufacturers, and the University can work together on a project that combines economic development with important research issues," said Bostian.
Photo: Engineers from Virginia Tech are developing prototype components for a wireless network. Components include a hand-held remote control device for transmission and a relay station. Shown above, graduate student Andy Harmon works with the prototypes in the Center for Wireless Telecommunications Laboratory. The components for the hand-held device are in the foreground, the relay station sits behind, and an antenna for the hand-held device is at the lower right.