Mtech Press Releases

FOR IMMEDIATE RELEASE
Novermber 6, 2002

A Distaste for Noise: How the Inventor of Pulse Doppler Radar and the University of Maryland Could Revolutionize Communications

COLLEGE PARK, Md.—Maryland alumnus Dr. Harry Smith doesn't like noise; in fact, he's made a lifetime of eliminating it.

During World War II he developed the first electronic machine to break German codes by sifting through the noise in numbers and breaking the enemy's encryption schemes—10,000 times faster than the Allies could before.

After that he invented Pulse Doppler Radar, which enabled planes to see other aircraft flying below through the glare—or noise, as Smith likes to call it—created by the Earth's reflection below.

Now Smith, his new company APEX/ECLIPSE Inc. (AESI) and University of Maryland researchers are going after the Holy Grail of communications system solutions—which is, aptly—reducing noise.

"Noise has always been the problem," said Dr. John Baras, the University investigator for the joint AESI/Maryland research project. "If you're trying to talk to someone on your cell phone and the weather is bad, you can lose the number of people who can communicate in a network."

Noise can come from weather, interference, or from other people talking. "The wireless medium is a shared medium," Baras explained, "so you need your signal-to-noise (S/N) ratio to be high so your signal goes through more easily."

AESI's system for improving that ratio is two-pronged: it involves APEX, a more directional super antenna, and ECLIPSE, a unique signal processing method that significantly reduces noise in communications. The APEX is formed by a group of tiny antennae lined up in a grid that enables them to form a very narrow beam—one that is much smaller than those formed by a single, larger antenna. "A narrow beam gives you less interfering signals," said Smith, "which allows you to install this antenna in an environment with lots of other signals."

The ECLIPSE portion of AESI's invention involves an algorithm that detects and pulls signals from noise in near real-time. The antenna receives information being sent while the algorithm, built into the receiving system, extracts the signal.

Baras, along with graduate student Amit Muckherjee, is working with AESI through a Maryland Industrial Partnerships (MIPS) program contract to model and simulate AESI's system—first in a wireless environment, and then through wire line communications channels.

The Maryland team has already proven that AESI's system can yield up to a 30 decibel S/N improvement. "If you had a 2 dB [reduction] you'd be a hero," said William Gretsch, chief engineer for AESI, "so this advancement promises to have a substantial impact."

That impact, according to Smith, could widen the bandwidth of a wireless system by up to 1,000 times.

The APEX/ECLIPSE system can be applied widely within communication systems. In a wireless environment, it can be exploited to yield greater channel capacity, more users, and reduced infrastructure—all translating to lower costs for end users. For wire line communications, the new system could give more customers access to Digital Subscriber Line (DSL) broadband Internet technologies, since it removes the single largest inhibiting factor for transmitting signals over longer distances—noise.

Baras is the director of the Center for Satellite and Hybrid Networks, and holds a joint appointment in the Institute for Systems Research (ISR) and the department of electrical and computer engineering at the University. His credits include DirecPC, the first satellite Internet product for consumers, which was developed by Baras and Hughes Network Systems through a series of MIPS awards.

Smith earned his Master's degree in electrical engineering from Maryland, as well as a degree in professional management. He is also a member of the A. James Clark School of Engineering's Innovation Hall of Fame, as well as a recipient of the school's Distinguished Engineering Alumnus award.

MIPS provides matching funds for joint industry/University research projects leading to commercial product or process development.

###