University of Southern California The USC Andrew and Erna Viterbi School of Engineering USC
The USC Andrew and Erna Viterbi School of Engineering
About Us
Prospective Students Current Students Alumni & Friends
Dean's Welcome
Dean's Report
About Viterbi
Dean's Message
Bold Ideas & Inventive Spirit
Family Fuels Journey of Discovery
USC Viterbi School at a Glance
USC Engineering - Digital Age
Algorithm: A Precise Rule Specifying How to Solve a Problem
Viterbi Algorithm
Viterbi Ad
Press Release
Coverage of the Event
Andrew & Erna Viterbi: The Journey and the Legacy
Facts
Administration
History
Timeline
Viterbi Museum

Home > About Us > About Viterbi > Algorithm: A Precise Rule Specifying How to Solve a Problem

ALGORITHM:
A PRECISE RULE (OR SET OF RULES) SPECIFYING HOW
TO SOLVE A PROBLEM

Andrew J. Viterbi with Irving Reed(left) and Gus Solomon. The Voyager spacecraft images were transmitted to earth using Viterbi packaging of Reed-Solomon codes.
 
Reed-solomon codes
In 1960, prior to joining USC, Irving Reed invented an elegant, powerful algebraic error correction code with his colleague, Gus Solomon. At first, RS codes were admired for their mathematical beauty, but considered too complex for practical use. But in the 1990s, RS codes became the standard error correction method on compact discs, fax machines and numerous other uses. Reed subsequently refined them and created more efficient decoders in further work at USC.
 
 
 
 
 
 
 

Spread-spectrum
synchronization/adaptive
iterative detection
Andreas Polydoros made significant contributions to two problems in dealing with cell phone-like signals decoded using Viterbi Algorithm processes. First, he found a better way to “find the beat” of an incoming signals and to synchronize them, and second, he was able to identify and locate signal groups in marginal reception conditions.

TCP/IP
The Transfer Control Protocol and the Internet Protocol form the foundation definition for transmitting data over the Internet. Among the scientists involved was Jon Postel of USC’s Information Sciences Institute, who from 1977 on worked with Vint Cerf and other innovators. Critically, in 1978, Cerf and Postel split what had a been a single TCP protocol into the TCP and IP protocols, and in 1979 and 1980, Postel wrote the definition of TCP/IP that remains at the base of Internet communication to this day.

Ultrawideband communications
Robert Scholtz wrote the earliest papers, obtained the first federal research grants and organized the first workshops in the mid-1990s in this new technology, which operates at a lower power than the wireless local area network standard known as Wi-Fi, but is capable of handling much larger amounts of data, including streaming video. Commercial applications begin in 2005.

The welch bound
Lloyd Welch established a mathematical basis for judging signal-set design, enabling engineers to determine directly how close to perfect are designs for spread spectrum communication systems.