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Home , Andrew Viterbi, Claude Shannon

Announcement Celebration

The Andrew and Erna Viterbi School of Engineering

University of Southern California March 2, 2004

“It’s the right time to turn a page and widen one’s horizons.”

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-10 9 12 16 Viterbi School of Engineering University of Southern California Los Angeles, California 90089-1454 AWGN Channel www.usc.edu/dept/engineering/ phone: 213.740.4750 The Viterbi : 213.740.8493 Revolutionizing how we communicate

design: warren group | studio deluxe

The Andrew & Erna Viterbi School of Engineering

Ninety-nine years after the first engineering classes began on this campus, we are proudly naming our school USC’s Andrew and Erna Viterbi School of Engineering.

No name could more appropriately capture the The Viterbi School is one of only four, and ingenuity and innovation that permeates this the only one in California, with two prestigious school. For Andy Viterbi is one of our own: National Science Foundation-funded Engi- a USC Ph.D., a USC Trustee, a member of the neering Research Centers. We have just become Board of Councilors, a pioneer in the global the site of the Department of Homeland spread of and a vision- Security’s first Center of Excellence. In the ary engineer and entrepreneur who gave birth fierce competitions for all of these centers, our to the cellular technology that connects hun- school placed number one. dreds of millions of people. This wealth of leading-edge research Try to imagine a world without Andy’s enables our Ph.D. students to spread new tech- inventions, and you’d have to travel back nologies around the world. Eight hundred in time  years — before cell phones, direct students are pursuing degrees through our broadcast satellite TV, deep space weather Distance Education Network, which delivers forecasting and video transmissions from the classes utilizing an innovative high-speed surface of Mars. interface designed here. Our under- With their generous gift of  million, the graduate curriculum is experiencing a dramatic largest ever received to name an engineering transformation. And our incoming freshmen school, Andy and his gracious wife, Erna, have have logged the highest average SAT scores at assured the future of the school with far more USC for the past two years. than the growth of our endowment. The inno- These talented young women and men 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 vative Viterbi spirit will inspire a new genera- will shape tomorrow’s world. Perhaps  years age

P tion of engineers and catapult The Andrew and from now, when humans are | Erna Viterbi School of Engineering into the the weather from Mars, we may be able to trace uppermost echelon of engineering schools. the origins of those technologies We are well on our way. For the past two to The Andrew and Erna Viterbi School of ngineering years, we have been ranked number eight out of Engineering. BOUNDLESS  engineering schools by U.S. News & World On behalf of the students, staff and fac- Report and fourth among private schools. ulty, I express our deepest gratitude to Andy and With more than  million in annual Erna for this gift and the boundless opportuni- research expenditures, our school consistently ties it opens for all of us. OPPORTUNITIES iterbi School of E

V ranks in the top three nationally in funding per na r tenured faculty member. Currently,  faculty are members of the National Academy of C. L. Max Nikias Engineering, the fourth-highest total among Dean ew and E the nation’s private universities. ndr The A Erna and BOLD IDEAS

Andrew J.Viterbi Bold ideas & an inventive spirit transform the world

Communications pioneer Andrew J.Viterbi — who in  earned one of the first doctorates in granted at the University of Southern California — has forever changed how people everywhere connect and communicate, whether from across a crowded city, between Andrew J.Viterbi – Los Angeles  nations or from the infinite reaches of space.

Born into an analog world, this visionary Sputnik, the world’s first artificial satellite, and courses in digital communications and infor- and another of Dr. Viterbi’s colleagues, Leonard thinker opened the doors to the digital age with the space race was on. mation theory. However, he found that the Kleinrock, shared an interest in forming a con- the Viterbi Algorithm, a groundbreaking math- The new MIT grad and his family moved needed to decipher convolutional sulting group. With an investment of , — ematical formula for eliminating inter- to California, home to defense industry giants. codes — those used to improve the perform-  from each man — the trio founded ference. Today, the Viterbi Algorithm is used He went to work at the California Institute ance of and satellite links — were too Linkabit. The company grew as it supplied soft- in all four international standards for digital cel- of Technology’s Jet Propulsion Laboratory, complex and difficult to explain to students. ware for government and performed lular , as well as in data terminals, then a center for communications and satellite His solution: create a brand new algorithm. simulations using the Viterbi Algorithm. By the digital satellite broadcast receivers and deep control , which soon became part At the time, only a handful of computers s, Linkabit began providing technology for space telemetry. of a new National Aeronautics and Space in the world could perform the millions of oper- defense communications satellites using very Dr. Viterbi’s lifelong interest in communi- Administration. There, he specialized in the ations required by his revolutionary algorithm. large antennas. cations began as a child, when his family fled communications technology of “spread spec- A capable of doing the calculations

01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 Italy for America in  to escape the persecu- trum” systems on a team that designed the rapidly would have demanded the energy of a An expanding tion of Jews. Long absences from family mem- telemetry equipment for the first successful U.S. particle accelerator. However, time would even- But the sophisticated transmission systems age P

| bers instilled a desire to find ways of communi- satellite, Explorer . Faced with a challenge to tually catch up with his vision. that emerged from the Viterbi Algorithm cating across political and geographical borders. process and transmit information packets from Dr. Viterbi’s first internationally regarded had reached their technological limits. Large space as accurately and quickly as possible, book, Principles of Coherent Communications, amounts of data sent from communications Theories into action the team confronted two problems: the satel- appeared in . A second, Principles of Digi- satellites required highly efficient integrated cir- ngineering The Viterbi family first settled in New York, lite’s weak signal, caused by its long journey, and tal Communications and Coding, followed in cuits, far more sophisticated than those avail- then Boston. He entered the Massachusetts frequency changes created by rapid orbits. . During this time, he remained dedicated able at the time. Dr. Viterbi and his Linkabit Institute of Technology (MIT) in , studying From this work, Dr. Viterbi developed the to his career in the UCLA School of Engineering associates came up with a breakthrough com- electronics and communications theory under topic for his Ph.D. dissertation at USC: error and Applied Science, conducting fundamental puter to accomplish the task and dubbed it a such renowned scholars as , correcting codes. research in digital communications theory and “,” even though it was made up iterbi School of E V , and Roberto publishing his findings in leading journals. of many chips. na r Fano. In , he met Erna Finci, married and Inventing a new paradigm Visionary ideas seemed to feed his entre- His renown grew as fast as the company. started a family. Dr. Viterbi’s love of new ideas in information preneurial appetite. In the spring of , In , Italy’s National Research Council In , the Cold War was underway. In theory led him first into an academic career. In Dr. Viterbi met Irwin Jacobs at a telecommuni- awarded Dr. Viterbi one of its highest academic ew and E October of that year, the Soviets launched , he joined the UCLA faculty, teaching cations conference in California. Both men, accolades, the Christopher Columbus Award. ndr The A

The Andrew and Erna Viterbi School of Engineering | Page 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 ANDREW J. VITERBI

Right: Andrew J.Viterbi receiving the Marconi International Fellowship Award from D. Allan Bromley, Science Advisor to the President, . Far right: Dr.Viterbi receiving decorations of the Grande Ufficiale della Repubblica from the Hon. Massimo Roscigno, Consul General of Italy, in Los Angeles, .

In , Linkabit merged with M/A-COM Dr.Viterbi traveled the country as CDMA’s Over the years, he has received numerous of Boston, remaining a separate division. It champion. Soon, flagship awards for his contributions to communica- soon produced the VSAT (Very Small Aperture companies, including , Motorola tions theory and its industrial applications, Terminal), the foundation for private satellite and AT&T, invested in the experimental tech- including the Institute of Electrical and communications networks. In , the VSAT nology. By , there were  million CDMA- Electronics Engineers’ (IEEE) Alexander division was sold to Hughes. The team of supported cell phones in the world, making Graham Bell Medal, the Marconi International Viterbi and Jacobs had a new dream: together, CDMA the dominant cell phone standard. “It Fellowship Award and the IEEE’s Shannon they founded Corp. to develop and was a team effort, and I’m proud of the part I Award and Lecture, considered the highest manufacture satellite communications and dig- played,” he said later. honor in technology. In , ital wireless telephones. When its doors opened During this period, his enchantment with he was named a “Grande Ufficiale della in , Dr. Viterbi was respected across the scholarship continued and Dr. Viterbi, who Repubblica” by the President of Italy.

01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 globe for his innovative ideas, as well as his resided in La Jolla, continued to teach part-time uncanny ability to turn scientific discoveries at the University of California, San Diego. In A life of leadership age P , he became a UCSD professor emeritus. Dr. Viterbi has received honorary doctorates | into profitable enterprises. USC honored his inventive spirit in  from universities in the , Canada, An experiment pays off with the USC School of Engineering’s Out- Italy and , and has been otherwise hon- Top: Andrew J.Viterbi signing In the s, Dr. Viterbi again capitalized on standing Alumnus Award and again in  ored in Japan, , Italy and the U.S. He ngineering for his Honorary Doctorate, his knowledge of technology. with the Graduate School’s Diamond Jubilee is a Fellow of the IEEE, a Marconi Fellow and a University of Waterloo, Canada. Bottom: Dr.Viterbi delivering the He and colleagues devised a new transmission Alumni Award. In , he joined the member of the American Academy of Arts and Commencement Address at UC Berkeley technology for cellular phones — CDMA, for USC Board of Trustees. Technion, the Israel Sciences, in addition to belonging to a select College of Engineering,. Code Division Multiple Access — which would Institute of Technology, invited him to become group of scientists who hold dual memberships provide simultaneous access to a multitude a distinguished visiting professor of electrical in the National Academy of Engineering and iterbi School of E

V of users, with less interference and greater secu- engineering. the National Academy of Sciences. na r rity for voice and data. According to his In March , Dr.Viterbi, then , stepped From  until , Dr. Viterbi own calculations, the network could have a down as vice chairman and chief technology served on the U.S. President’s Information capacity  to  times greater than a traditional officer of Qualcomm, saying, “It’s the right time Technology Advisory Committee and, since ew and E analog . to turn a page and widen one’s horizons.” , has been active on the MIT Visiting ndr The A

The Andrew and Erna Viterbi School of Engineering | Page 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 The Andrew and Erna Viterbi School of Engineering | Page 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 University ofRome (Tor Vergata). . University ofNotre Dame, Doctorate atthe Middle: Dr.Viterbi receiving anHonorary Academy ofSciences, Washington, on becomingaMember ofthe National Top: signingregister Andrew J.Viterbi Bottom: Doctoral Lecture atthe DC, . and Erna Viterbi ChairinCommunicationsat Council fortheNational Laboratories. USC . Committee forElectrical Engineering and discover next? of Engineering. Who knows whathemay again —atnoneotherthanthe Viterbi School dition, hehasacceptedanoffertoteach network infrastructure andimaging.In ad- predominantly inwireless communications, advises andinvests inearlystagecompanies, in Berkeley andamemberofthe the Mathematical SciencesResearch Institute Scripps CancerCenterinLaJolla, of atrustee the board oftheBurnham Institute andthe Viterbi alsoison ing Board ofCouncilors,Dr. as presidentthe of Viterbi Group, connect, learnandexplore. He currently serves Viterbi continuestoshapeourability Dr. in digitalandspacecommunications. holder, Professor Solomon Golomb, isanexpert He andhiswifeestablished The Andrew A memberofthe Hailed by hispeers asadigitalgenius, in  . Appropriately, thechair’s first USC School ofEngineer- UC LLC President’s , which NRWJ VITERBI ANDREW J. from left)andotherdignitariesatthe (backrow,Andrew J.Viterbi farright)withPresident George W. Bush (front row, third  Notre Dame CommencementExercises. The Andrew and Erna Viterbi School of Engineering | Page 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 Family FuelsaJourney ofDiscovery five years. injust degrees incommunication theory track, earningbothhisbachelors andmasters ber prepared fortheirescape. them. Achille Viterbi closedhispracticeand Italians were informedthatItaly hadrenounced Suddenly, peoplewhohadcalledthemselves was Italy’s small,integratedJewish population. raciallawswhosemaintarget lini passednew world-famous home inBostonandimaginehimselfattending gaze across theCharlesRiver from hismodest of animmigrantItalian Jewish family, would At Luria, ahomemaker. parents, Achille, anophthalmologist,andMaria in Bergamo, Italy, ofMilan, northeast with his in hisclassof Joseph Viterbi Kennedy.graduatedfourth Dr. and almamaterofBenjamin Franklin and Latin High School,thenation’s oldestschool time toBoston. Within twoyears, thefamilymoved again,this safely inNew York, where acousinlived. tip, the Viterbis lefttwoweeks early, landing for hisinvasion ofPoland. However, actingona the “Father ofRadio.” of hisheroes, , considered wanted tobeanengineer, inthetraditionofone not toobigforsomeonewhoalready he knew had fledfascistItaly onlysixyears before, but matic entry into a new land. intoanew matic entry love. Amongotherthings,they shared adra- changed hislife.He metErna Finci andfellin   In In Their proposed sailingdatewasSeptem- But in There, Andrew Viterbi attendedBoston At At Born in It wasabigdream foraboy whosefamily — alsothesecret dateHitler hadchosen years old,Andrew J. Viterbi, theonlyson MIT   , heimmediatelywent onthefast , anotherevent occurred that   MIT , theregime ofBenito Musso- , Andrew Viterbi firstresided in .  . Erna – &Andrew J.Viterbi Wedding, . Above left:Children –Alan, Alexander, Audrey, five days, the Viterbis, Mangini and teacherGiorgio Mangini.School history Over had beencorresponding withPaolo Sarpi High returned toBergamo, Italy, where Dr.Viterbi war, finallysettlinginCalifornia then Switzerland, where theywaitedoutthe little girlcry.” said anItalian officer. “Idon’t wanttoseethis handcuffs, sheburstintotears.“Letthemgo,” grandfather andtwouncles.Seeing themin Among themwere Erna’s fatherJoseph, her army arrested alargenumberofcivilians. upatroopblew carrier. In reprisal, theItalian reached theItalians inMontenegro, partisans German armymoved in. When thefamily and parents hadfledSarajevo, Yugoslavia, asthe Marconi proud. ema. It’s acontinuinglegacythatwouldmake preneur; andAlexander, indigitalcin- anexpert ness.” Audrey isa own children have gone intothe“family busi- Viterbi aswell. isalwayslookingforward His Viterbi fullcircle. journey brought Dr. ovens.camps andcrematory The emotional Republic, visitingremains ofconcentration traveled by bustoAustria andthe Czech and Alexander—played. notepad whiletheirchildren —Audrey, Alan lost inthoughtonthecouch,scribblinga tion theory, Erna wasthere. She remembers him wrote papersoncommunica- When Dr.Viterbi family moved permanentlytoLosAngeles. father, of Viterbi Group, communications andco-founder, withher The Finci familyescapedtoParma in Italy, However hemaylookback,Andrew In April In In During World War Middle: Erna –Los Angeles,  , Andrew Viterbi andhisnew  Ph.D , ErnaAndrew and Viterbi . engineerinvolved in LLC  , Erna, herbrother ; Alanisanentre- .   students . . Right: mpeg compression standards andnumerous pattern recognition systems. Grid architecture. Its Home oftheInformation SciencesInstitute Systems Center(established 2003). (established 1996,renewed 2001)andtheBiomimeticMicroElectronic Engineering Research Centers:theIntegrated MediaSystems Center California, that housestwo active National Science Foundation-funded One ofonly fourengineeringschoolsnationwide, andtheonly onein Consistently ranksinthetop 3nationally infundingper tenured faculty. Research funding:more than $135millionannual research expenditures. sities). 2002ranking:#8. 24 (with other centers)the planetary communications, cellphones andnumerous other applications. Internet technologies, including theDomainName System USC USC Ranked #8in Shannon Award andthe2003 Turing Award co-winner. (4th highesttotal amongprivate universities), including 3winnersofthe Academic homeof22memberstheNational Academy ofEngineering Faculty: 165(Tenure or Tenure Track). Research Faculty: 75. Degrees awarded, 2003:512 Enrollment: Undergraduate 1,878.Graduate 3,325. Basic research at Institutes ofHealth. center hasreceived more longstanding support from theNational state-of-the-art biomedicalmodelingandsimulation. No other research Home oftheBiomedicalSimulations Resource, whichisadvancing in industrialdevelopment ofnumerous widely usedchips. M.S. researchers’ error correction andsignal codes are usedin Engineering Distance Education Network: More than800students in degree programs; 99mastersdegrees awarded in2003. U.S. N USC EWS or by & W TCP/IP B.S ORLD USC ., 950 R researchers formsthebasisofjpeg and protocols. MOSIS EPORT M.S ., 85 , 2003(4thamongprivate univer- chip brokerage was instrumental Ph.D. ISI co-developed theGlobus (ISI) , birthplace ofkey CD (DNS) s, inter-

and

| | E S V USC NGINEERING CHOOL ITERBI OF t a gl a t A ance ance Right: Andrew J.Viterbi lecturing at Technion in Haifa, Israel. Far right: Dr.Viterbi with “Pioneers” Steve Rice and John Costas at IEEE Communication Workshop, . VITAL CONTRIBUTIONS

USC Engineering — Cradle of the Digital Age

Andrew J. Viterbi’s inventions — led by his of their careers when Claude Shannon of MIT stepwise fashion — so-called Markov processes. Pseudorandom sequences/shift influential algorithm — are just one aspect of published his landmark  paper on . It has become an important tool in many fields, register sequences what has long been a major strength of USC’s All three, and Dr.Viterbi, would eventually win led by , and gained recent In , Solomon Golomb published the first Andrew and Erna Viterbi School of Engineering: the Shannon Award, the highest honor from the additional celebrity as a key component of the book devoted exclusively to pseudorandom digital information technology. Society of the Institute for turbo-decoding systems that functions, as the sequences, also known as shift register Since the early s, researchers at or Electrical and Electronic Engineers. name indicates, with unparalleled speed. sequences. As the technology of digital commu- connected to USC have played a central role At a time when information was transmit- nications has evolved, these sequences have in the transmigration from the old world ted using continuous analog waveforms, Domain name system (dns) played a central role in many applications, of analog signals to the digital domain we Shannon conceived that all signals — whether The Internet depends on a flexible, stable sys- including digital CDMA cell-phone systems inhabit today. for use on a , radio or — tem to regularize, distribute and store names. and “direct-sequence spread spectrum” secure USC engineers have made vital contribu- could be decomposed into zeros and ones, In , at USC’s Information Sciences Insti- military communications. They are widely used tions to the theoretical understandings and sci- encoded, transmitted and decoded at the other tute, Paul Mockapetris devised a system to solve in limited-access security systems, “stream- ence of computers and to the basic tools com- end. Shannon determined a maximum rate of this problem, with the potential to add an ” , and jam-resistant missile puters depend on to operate and communicate. transmission on a single channel and posited almost unlimited number of new addresses. In guidance systems (for generating efficient, Such everyday items as the compact disc, fax that adding enough redundancy to the trans- addition to organizing numerical addresses, continuous wave radar signals), as well as in machine and cell phone use technology rooted mitted signal would enable receivers to decode Mockapetris and the late Jon Postel introduced implementing the encoding and decoding of in USC research. Interplanetary communica- the message accurately no matter how noisy the now-ubiquitous .com, .gov, .edu, .org, suf- many error correcting codes, including Reed- tion signals from Voyager to the Mars Rovers the channel. fixes, as well as country codes. Solomon codes. are kept pristine with error correction systems Shannon’s insights were theoretical. But, created at USC. to a remarkable degree, Golomb, Reed, Welch & recognition Quaternary (z4) error 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 Critical elements of the Internet began at and their students and colleagues — including William Pratt was among the first to study correction codes/ cellular age

P USC, including the powerful system for Andrew Viterbi — turned theory into working methods of analyzing and storing data that In , Vijay Kumar, working with his Ph.D. | robustly coding and decoding digital signals. signaling systems. That work continues today recorded visual images in compressed form. student, Roger Hammons, Jr., discovered a hid- Also born here: the now-familiar technologies with a new generation of USC electrical engi- Harry Andrews explored methods of recogniz- den regularity in existing error codes, which led and Internet fundamentals of jpeg and mpeg, neers such as Alan Willner and Keith Chugg. ing shapes — initially, printed letters — in digi- directly to improvements and added efficiency ngineering used by computers worldwide to store, transmit Here are some of the landmark contribu- tal files. The work of Pratt, Andrews and subse- in CDMA cell coding. Rather than encoding and restore still and video images. tions by USC-associated researchers to the quently Andrew G. Tescher led to today’s jpeg binary messages, Kumar’s codes employ quater- The digital ancestry of today’s Andrew and : compression system for still images. The parallel nary (,,,) values, which are at the basis of Erna Viterbi School of Engineering was fixed in mpeg system, which compresses video images, sophisticated new “third generation” (G) signal the early s by that era’s legendary dean, The baum-welch algorithm also has USC roots. Jay Kuo and Antonio Ortega equipment, that carry information four times iterbi School of E

V Zohrab Kaprielian. Under his leadership, three The Baum-Welch Algorithm developed by are continuing USC research into video com- as efficiently.

na great mathematical and information theorists Lloyd Welch in collaboration with Leonard pression, while Irving Reed created his own sys- r joined the USC electrical engineering faculty. Baum is, like the Viterbi Algorithm, a powerful tem of image compression, adopted by AOL. Solomon Golomb, Irving Reed and Lloyd tool for examining and analyzing the results of

ew and E Welch were all young scientists at the beginning continuing processes that proceed regularly in ndr The A

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ALGORITHM: The Viterbi Algorithm A PRECISE RULE (OR SET Yielding Clear Communications

OF RULES) SPECIFYING HOW The Viterbi Algorithm — theoretical basis for such wide-rang- ing applications as cell phones, DNA analysis and speech recog- TO SOLVE A PROBLEM nition — is essentially a fast way of eliminating dead ends. Imagine you’re a detective trying to determine the point of origin for a suspect arriving at the Seattle airport. He is from abroad and has been there for no more than an hour. You know during this period that four domestic flights arrived from four cities served by flights from  others. One way to determine the suspect’s origin would be to go back to all  and make inquiries. The alternative: identify which of the four closest cities he arrived from, then investigate only TCP/IP 0100 01 00 00 0 -1 -1 -2 -2 -2 places with connections to that one. The Transfer Control Protocol and the Internet The algorithm Andrew J. Viterbi invented in , and Protocol form the foundation definition for published the following year, is much more subtle and flexible -1 -3 -2 -2 -3 transmitting data over the Internet. Among the Andrew J.Viterbi with Irving Reed (left) than this simple illustration. But the basic situation and strat- scientists involved was Jon Postel of USC’s egy are the same. For an algorithm is merely a precise rule (or and Gus Solomon.The Voyager spacecraft -2 -2 -3 -3 images were transmitted to earth using Information Sciences Institute, who from  set of rules) specifying how to solve some problem. A user starts Viterbi packaging of Reed-Solomon codes. on worked with and other innovators. with the result of a set of changes that happened in a series — Critically, in , Cerf and Postel split what not a random series, but one governed by known, rigidly for- had a been a single TCP protocol into the TCP -2 -3 -3 -3 mulated rules. and IP protocols, and in  and , Postel The algorithm takes the result and backtracks, throwing BSC Reed-solomon codes wrote the definition of TCP/IP that remains at away all the branches that, by the rules, couldn’t have lead to In , prior to joining USC, Irving Reed the base of Internet communication to this day. +1,+5-1,+3 +2,-3 +3,+6 +7,-1 the observed result. 0 6 8 7 16 22 invented an elegant, powerful algebraic error When he created his system, Dr. Viterbi specifically fo- correction code with his colleague, Gus Ultrawideband communications cused on electronic signals encoding messages. To transmit -6 4 9 8 18 Solomon. At first, RS codes were admired for Robert Scholtz wrote the earliest papers, messages so they won’t be degraded or lost by noise, additional their mathematical beauty, but considered too obtained the first federal research grants and “redundant” information is added at the , in a complex for practical use. But in the s, RS organized the first workshops in the mid-s process called error correction coding. The result coming into codes became the standard error correction in this new technology, which operates at a -2 -1 12 20 a receiver is a pulsing, miscellaneous stream of , ones and method on compact discs, fax machines and lower power than the wireless local area network zeros. The signals aren’t clear zeros and ones, but values on a numerous other uses. Reed subsequently re- standard known as Wi-Fi, but is capable of -10 9 12 16 sliding scale that the receiver has to designate as zeros and ones, 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 fined them and created more efficient decoders handling much larger amounts of data, includ- as best it can. age AWGN Channel P in further work at USC. ing streaming video. Commercial applications Thanks to the Viterbi Algorithm, this sliding confusion | begin in . The Viterbi Algorithm of radio waves can yield a clear, undamaged message. The key Spread-spectrum rests in a time series of incoming information, with each set of synchronization/adaptive The welch bound bits tagged by its order of arrival. ngineering iterative detection Lloyd Welch established a mathematical basis The element sample — up to  time sequences deep in Andreas Polydoros made significant contribu- for judging signal-set design, enabling engineers the latest, most sophisticated versions — is probed for a mes- tions to two problems in dealing with cell to determine directly how close to perfect are sage by working back in time. Instead of analyzing all possible phone-like signals decoded using Viterbi designs for spread spectrum communication messages in this stack, the algorithm swiftly finds the most Algorithm processes. First, he found a better systems. probable one, throwing away more and more possibilities with iterbi School of E

V way to “find the beat” of an incoming signals each layer.

na and to synchronize them, and second, he was

r At the time Dr. Viterbi published his algorithm, comput- able to identify and locate signal groups in mar- ers weren’t up to the task of even a relatively shallow decoding. ginal reception conditions. With the growth in computing power, the Viterbi Algorithm ew and E swiftly came of age as a powerful, useful tool for ensuring ndr static-free voice communications over satellite links, with cell phones its current showcase “killer application.” The A The Andrew and Erna Viterbi School of Engineering

Innovator, entrepreneur, scholar, teacher, colleague, engineer.

Andrew J.Viterbi

has devoted his professional life to helping us reach across

the divide of space and understanding.

01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 Blessed with a new name that signifies our rich heritage and inventive age

P spirit, The Andrew and Erna Viterbi School of Engineering | is on a course for the future. ngineering We are profoundly appreciative of Andrew and Erna Viterbi’s

philanthropic leadership, commitment and inspiration.

Guided by their example, we will continue our quest for the iterbi School of E V ideas and solutions that can transform our world. na r ew and E ndr The A