- Person
- Andrew Viterbi
- Lived
- b. 1935
- Field
- Communications engineering
- From
- Italian-American
The story
Andrew Viterbi was born in Bergamo, Italy, in 1935 into an Italian Jewish family. After Mussolini’s racial laws of 1938 cost his father, an eye surgeon, his hospital post, the family fled, sailing for New York in August 1939. Viterbi grew up in Boston, studied electrical engineering at MIT, and worked on telemetry for early American satellites at the Jet Propulsion Laboratory before becoming a professor at UCLA.
Every digital signal sent by radio arrives with errors, as noise and interference flip some of its ones and zeros. Engineers add structured redundancy, called error-correcting codes, so the receiver can repair the damage. One powerful kind, convolutional codes, was hard to decode, because checking every possible original message against the noisy one received quickly becomes impossible.
In 1966 Viterbi found an elegant solution, published in 1967. His algorithm moves through the received signal step by step, keeping only the most likely path that could have led to each possible state and discarding all the others, so the work grows only modestly with message length. It finds the most likely message that was sent. On a lawyer’s advice, Viterbi did not patent the algorithm, so engineers everywhere could use it freely.
The Viterbi algorithm became one of the most widely used algorithms in engineering. According to the USC school that bears his name, it has been used in all four international digital cellular standards, as well as in data terminals, satellite broadcast receivers and deep-space telemetry. Because it finds the most likely hidden sequence behind noisy observations, it is also used in speech recognition and in analysing DNA sequences. Viterbi went on to co-found Qualcomm and help develop CDMA cellular technology.
The decision not to patent the algorithm was made on a lawyer’s advice, but its effect was to let the algorithm spread into products everywhere without licensing barriers. He and his wife Erna went on to give 52 million dollars to the University of Southern California in 2004, and its engineering school now bears their name.
Why it matters
The Viterbi algorithm helps billions of phones, satellite receivers and spacecraft recover clear digital signals from noise, every day.
About Andrew Viterbi
Refugee from Fascist Italy whose Viterbi algorithm decodes digital signals in phones, satellites and space probes, and who co-founded Qualcomm and helped build CDMA mobile networks.
Sources
- Andrew Viterbi Wikipedia
- About Andrew J. Viterbi USC Viterbi School of Engineering
- One Family, Two Diverging Experiences in Fascist Italy Primo Levi Center
Another act of tikkun olam. This is part of tikkun olam, the Jewish idea of repairing the world, and every one of us can add to it.