Entire industries can start from a simple idea—a drawing scribbled on a napkin, or a hobby that unexpectedly grows into a full-time endeavor. Bill Gates dropped out of Harvard to play around with new computing devices. Bill Hewlett and Dave Packard started selling electronics from a makeshift workshop in a single-car garage—now designated as a California historic landmark and widely regarded as the birthplace of Silicon Valley.

For every invention that is doggedly pursued until a goal is reached, dozens can be found accidentally or unintentionally. In 1968, a researcher at Minnesota Mining and Manufacturing (3M), attempting to improve tape adhesives, considered a semisticky substance that held for an unusually long time despite its relatively low adhesiveness to be a failure. Then, years later, 3M found a blockbuster application for this tacky backing in its line of Post-it notes, the hugely profitable repositionable notepaper.

In 1886, John Pemberton, an Atlanta pharmacist, developed the original formula for Coca-Cola, using the coca plant and kola nuts, as a nerve tonic for people who were feeling under the weather or fighting an addiction. You can probably guess the rest of that story. Many novel inventions take decades to find a suitable use, while others never do.

But the founders of Qualcomm and the team that backed them had no such problems applying their radical communication solutions. From the outset, they knew exactly where they were going. No one knew how successful they would be, or how their ideas would be received in the marketplace, but there was definitely more purpose to their inventing than just getting a few patents under their name.

The story of how Qualcomm found its niche in advanced communications starts with the origins of what is called spread-spectrum technology. Clever engineers at Qualcomm devised ways to apply this new, radical, and advanced communications concept to everyday communication products around the world. But the theory underlying their work goes back to World War II, when communications came to play an increasingly vital role on the battlefield.

And in this case, the inventor was not someone most people would have expected. In fact, she was an entirely unexpected inventor.


The Mother of Spread Spectrum

A wide chasm can separate an inventor from a pioneer, and an accomplished visionary from a successful inventor. Visionaries conceive and enlighten, while inventors resolve and implement, and the two sets of characteristics are rarely found in one individual. The inner workings of spread-spectrum communications, upon which Qualcomm’s code-division multiple-access (CDMA) technology was based, are derived from an earlier discovery by an unlikely source—a beautiful and insightful actress named Hedy Lamarr (see Figure 1-1).

Born Hedwig Eva Maria Kiesler in 1913 in Vienna, Austria, Lamarr’s controversial nude appearance in the film Ecstasy in 1933 secured her an acting career that would eventually include appearances in many other popular features, such as Samson and Delilah and White Cargo. That same year, she married the first of her six husbands, Austrian industrialist Friedrich (Fritz) Mandl. Most people saw Hedy Lamarr as simply a showpiece for a powerful tycoon, like many other famous wives. But many would later be surprised to discover her interest and competency in technology and the science of advanced warfare.

Her marriage to Mandl landed her in the middle of interesting conversations on current warfare techniques, as her husband was an arms manufacturer who was doing more and more business with the Nazis. One topic he and his colleagues often discussed that interested Lamarr was the radio control of torpedoes. In battle, naval fleets launched torpedoes from their hulls and then used radio signals (from a plane or ship) to guide the speeding bombs toward their targets.

Figure 1-1

Unfortunately (assuming you were the one sending, not the one receiving, the torpedoes), jamming the radio signals was a common countermeasure that made the torpedoes far less accurate in reaching and destroying their targets. Since early communications were transmitted on a single frequency channel at a time, an enemy had simply to detect that channel and then blast enough electromagnetic noise to effectively jam the signal (in much the same way that driving under power lines can render music or speech on an AM radio station incoherent). It was no secret that developing a means to avoid direct jamming would greatly increase the effectiveness of naval fleets, but a solution to the problem was elusive. While most of her husband’s colleagues assumed that Lamarr had no clue about her husband’s work, she later returned to the challenge of guiding torpedoes and showed that there was more to her than just a beautiful face.

Lamarr became increasingly repulsed by the Nazi regime and her husband’s involvement with it, and in 1937 she decided to escape her caged existence. After fleeing Austria, Lamarr moved on to Hollywood after Louis B. Mayer of MGM convinced her to sign a movie contract with the company (when she adopted the name Lamarr). With a new life and a film career in full swing, Lamarr met popular composer George Antheil at a Hollywood dinner party. The two teamed up in what was to become one of the most unlikely pairings to support the U.S. war effort.

It turned out to be a natural fit—Lamarr’s interest in technology was complemented by Antheil’s knowledge of music fundamentals. The two started spending more time together—not courting, but rather discussing how to solve the problem of American torpedoes being jammed by Nazi signals. Antheil helped Lamarr discover through music the key to communication methods that were immune to the then-current jamming techniques.

Antheil had become well known for developing symphonies using several instruments and sonic mechanisms. Some works called for coordinating several automated player pianos, drums, gongs, and even airplane propellers. The artist never heard some of these symphonies, as synchronizing all these unusual instruments successfully was impossible at the time. But this did not deter Antheil from accurately describing how such synchronization could be done. Today, musicians and composers use powerful computers to play his symphonies. Though Antheil credits Lamarr with being the brains behind their joint developments, there’s no doubt that his vision of synchronization influenced what was to become Lamarr’s concept for discrete radio communication.

The initial concept for their torpedo guidance system was literally scribbled in pencil on an envelope from Antheil’s home. A sketch of the communication method on the back was accompanied by a short description on the front. The basic idea for this novel concept, which eventually became known as frequency hopping, was thus immortalized on a scrap of paper. Lamarr and Antheil captured the main principles of a jam-proof communication system in a simple picture and little more than a hundred words. The essential idea entailed jumping from frequency to frequency to elude jamming. The challenge involved synchronizing the hops of both the sender and the receiver—as in musical orchestration. The system could be scaled from relatively crude to ultrasophisticated, depending upon the degree of secrecy necessary and the intricacy of the technology used.

Lamarr and Antheil spent more time working out the details of how their idea would be implemented and pitched the concept to the National Inventors Council, which was headed by Charles F. Kettering. Started in early 1940, the council culled ideas from the general public and encouraged support for the war effort (especially from women). Kettering suggested that they continue to develop their idea into functional form, while others encouraged Lamarr to instead put her star power to use in selling war bonds (which she did very successfully as well).

Antheil and Lamarr’s work culminated in U.S. Patent 2,292,387, “Secret Communication System,” granted on August 11, 1942. The patent, filed under her then married name of Hedy Kiesler Markey, describes how a torpedo can be guided by a method of communication that hops among carrier frequencies at a regular time interval (one of the patent diagrams is shown in Figure 1-2). The synchronized changing of the carrier frequencies used by both the sender (a high-altitude airplane) and the receiver (an active torpedo) was controlled by identical player piano rolls marked with a unique sequence of eighty-eight possible steps (the number of keys on a piano).

"I read the patent. You don't usually think of movie stars having brains, but she sure did."
- Franklin Antonio,
Qualcomm Founder¹

This meant that the torpedo could be steered by sending only small portions of the entire message on each frequency. Attempts to jam the communication would typically render only one of the channels useless at a time, and the information on the other channels would be enough to enable the torpedo to make the necessary course corrections to reach the target.

What Lamarr and Antheil gave the U.S. military and the world was the concept of frequency hopping, which broke the conventional mold of communicating over a single frequency—the method that had been used since the inception of radio. Today’s spread-spectrum communications techniques are derived from this concept of using multiple frequencies to transmit information. And even though spread-spectrum technology contains many more novel elements, Lamarr and Antheil’s elegant frequency-hopping concept remains an integral component of many spread-spectrum implementations.

Unfortunately, neither Antheil nor Lamarr made any money from the ideas captured in their patent, even though it is the basis for hundreds of others that followed. Out of a sense of patriotism, both decided to donate the patent to the U.S. war effort. Few people understood the profound implications of this discovery at the time, but it marked a transformation from narrow thought and opened up the wide world of spreading communications across frequencies. Even though no one could make the device described in the patent function at the time, the U.S. military classified the patent and held the concept under tight security for decades.


Military Applications

Very little is openly known about early military experimentation with the frequency-– hopping concept that Lamarr and Antheil had so brilliantly laid out in their patent. Since the patent described a mechanical means of switching frequencies, the actual implementation of a device using the parts described was nearly impossible because of the speed and accuracy required. Many people figured that the mechanical piano rolls could not be synchronized and switched fast enough to produce reliable communication. In addition, Antheil himself noted that the player piano mechanism described was probably a poor choice to use in pitching their concept to the high levels of the military. He figured that they had surely laughed at the notion of installing player pianos in their torpedoes. As far as anyone knows publicly, the United States was never able to frequency-hop a torpedo into a Nazi cruiser during the war.

Figure 1-2

One of the earliest known implementations of frequency hopping while it remained classified was in the mid-1950s. It involved two-way communication between aircraft and devices called sonobuoys—cylindrical devices that were dropped into the ocean by airplanes to search for enemy submarines by using sonic emitters and sensors to listen for submarines in the area. Several buoys placed in a pattern could triangulate the position of a submarine.

The Hoffman Radio Corporation was given a contract by the Navy to build the sonobuoys and the accompanying airplane radios, and the Hoffman engineers were given the Markey-Antheil patent upon which to base the design. The names of the inventors were removed from the document, and the information was given under extreme secrecy, with the U.S. Navy offering information only on a “need to know” basis. Since the patent was dated more than a decade earlier, the engineers at Hoffman figured that the advanced concept came from some brilliant engineers in the military or defense sector. Little did they know that they were exploring one of the earliest implementations of the brainchild of a beautiful actress and a creative composer.

Frequency hopping played a vital role in retrieving the data from the sonobuoys. The sonobuoy used a mechanical spool that had protrusions spaced around its circumference in a unique pattern. The protrusions activated individual switches as the spool rotated at a fixed rate, with each switch representing a different frequency. The airborne radio communicating with the sonobuoy carried an identical spool to match the frequency hopping, which took place at a rate of approximately thirty-six hops per second. To talk to multiple buoys, the plane’s radio used several spools, one for each buoy, making communication with each buoy secure and undetectable.

This implementation of a mechanical device for frequency hopping was actually not far from what Antheil helped Lamarr convey in their patent using piano rolls. By today’s standards, the sonobuoys used a crude and simple implementation of a complex concept, but they were sophisticated for their time, considering the challenge of synchronizing the communication. Many other engineers at Hoffman and elsewhere later went on to develop more products under military contract using frequency hopping, among them an unmanned surveillance drone that was used in the Vietnam War. This implementation in the 1960s, however, took advantage of new digital computing technologies rather than mechanical means for frequency hopping. All the while, the source of the original patent and the diagramed techniques was unknown to communications engineers. (Spread-spectrum technology was not declassified by the U.S. military until 1981.)

Over time, the development of the electronic transistor made the implementation of frequency-hopping techniques much simpler. The move from mechanical to electronic means of frequency synchronization fueled its widespread implementation. The concept of frequency hopping fit naturally with digital technologies, since the communication channel needed to change at discrete points in time. Though this was dramatically different from the conventional radio wisdom of the time, the necessity for jam-proof communications in the military drove ongoing work in spread-spectrum techniques.

It is certain that the U.S. military and its allies initiated scores of new implementations of frequency-hopping techniques in the decades following the original patent, many of them probably unknown to the public. The benefits of secure communication that also had improved immunity to noise and interference certainly made the technology a prime candidate for any new communication projects at the time. The first widespread military use of the technology that the public at large saw came in the form of covert communication between the ships forming the naval blockade during the Cuban missile crisis in 1962.

By the time the Markey-Antheil patent was on the verge of expiration in 1959, researchers around the United States were delving into all sorts of applications for frequency hopping. The Russian launch of Sputnik I in October of 1957 marked the beginning of the space flight era and galvanized the United States to move further into communications research. One of the organizations that had teams working on advanced communication projects was the Jet Propulsion Laboratory (JPL) in Pasadena, California. A mathematician there, Dr. Solomon W. Golomb, was working on what would eventually became the primary form of spread-spectrum communications used today. Of equal importance—at least for this story—was that Golomb had a very bright colleague on his team named Andrew Viterbi (see Figure 1-3).

Figure 1-3. Andrew Viterbi.

Friends and Colleagues

After receiving his master’s degree from MIT in 1957, Andrew Viterbi went to work for the Jet Propulsion Laboratory’s Communications Research Section in the summer, starting out on the Explorer I project under director Eberhard Rechtin. He began working side by side with researchers and engineers implementing some of the first – attempts at satellite telemetry—using orbiting satellites to transmit measurements, observations, and other data.

Overcoming the challenges of satellite communications impelled Viterbi to significant achievements in the development of phase-locked loops and digital modulation techniques. (Phase-locked loops were the hardware portions of a radio that tracked and locked on to a frequency that was carrying information of interest. Digital modulation encompassed a variety of techniques used to embed as much information as possible into a carrier signal, and also extract the information once it was received.) Both technologies were necessary for reliable and effective communication over great distances, and both were largely undeveloped and untested at the time. Viterbi’s exposure to new digital electronics theory at JPL was to become the basis for a majority of his life’s work.

"By 1960 we were heavily into digital communications on the theoretical side and doing the first experimental work."
Andrew Viterbi, Qualcomm Founder²

In 1963, a year after finishing his Ph.D. work in digital communications at the University of Southern California, Viterbi became a member of the faculty at UCLA. As a professor, he was forced to broaden his horizon to include – information theory, a related but separate area that he had not been formally educated in during his days at MIT and USC. Through his continued consulting work at JPL and the classes he taught on information theory, he developed a passion for this area, where coding principles played pivotal roles in reliable communication.

During Viterbi’s time at JPL, he met many other researchers who were excited about the prospects of digital communications theory. Late in 1964, a visiting professor on sabbatical from MIT arrived at JPL, joining as a NASA Resident Research Fellow. This marked the beginning of a long and fruitful relationship between Viterbi and Irwin Mark Jacobs (Figure 1-4)—one that would change the world of communications forever through their cofounding of Qualcomm.

Viterbi and Jacobs had known of each other previously—they had shared an award from the National Electronics Conference for their presentations in 1963. But the time they spent together at JPL was the start of their working relationship. While both of them had been educated at MIT during the same time period, they had had different interests, and Viterbi had left for the West Coast while Jacobs stayed on the faculty of MIT. Jacobs’s decision to stay was largely prompted by the groundbreaking work of one man—Claude Shannon.

Figure 1-4. Irwin Jacobs. Courtesy Qualcomm Inc. 

The Father of Modern Communications Theory

Claude Shannon is widely credited with some of the most profound advances in information theory. Sometimes articulated in very simple and unorthodox ways, Shannon’s ideas for the most efficient methods of transferring information over any medium sparked a new era. Being a mathematician, Shannon formulated his theories in terms that are mostly beyond comprehension by the layperson. But to those educated in engineering, the concepts that Shannon expressed in mathematical formulas were an astounding break from the traditional focus of communications. Above all, Shannon broke down many complex problems of the day into very simple parts—a skill that many people say set him apart from numerous other capable minds of the time.

Shannon’s theories laid the groundwork for a new phase of exploration in communications by simplifying the approach to developing such systems. Shannon is often cited as being the one who could see the big picture in problems that faced communications engineers—the one who could see the forest for the trees. For instance, Shannon’s strategies for finding a suitable means of coding a stream of information focused on first understanding the characteristics of the medium the information was to be transmitted through. In fact, Shannon was the first to completely characterize a variety of communication systems in measurable ways so that engineers could optimize them.

Shannon developed his information theories to take into account the secrecy, reliability, and capacity required in any communication system. Given the vital role that intelligence had played in World War II, many were interested in Shannon’s theories of coding and encryption. But others were interested in using the fundamental concepts he laid out to characterize the capacity and information-carrying potential of telephone systems.

Perhaps the most important aspect of Shannon’s theories was his description of information in terms of bits—simply 1’s and 0’s (bits is shorthand for binary digits). This binary code was the simplest way to express any content that was being communicated—whether it was a voice, a picture, or other data. His suggestion that all information could be transmitted, stored, and manipulated digitally launched a revolution in communications and spawned the Information Age. This era would go on to be one of the most important phases of the twentieth century, with many other great minds adapting his theories to real problems.

"I like to find ways of understanding more intuitively what's behind the formulas."
-Irwin Jacobs, Qualcomm Founder³

The young and bright Irwin Jacobs had originally intended to pursue studies in electromagnetics. But his exposure to Shannon’s work while at MIT changed his mind. When Jacobs graduated and joined the faculty at MIT in 1959, his office was situated only a few doors down from Shannon’s. Several instructors and students at the time recall that period as one of the most exciting and combustible learning environments they ever experienced. There were so many breakthrough ideas at MIT that were opening up the world of information theory that the nascent area was too attractive for Jacobs to pass up.

The mathematical models and formulas that Shannon was developing and presenting to the staff and students intrigued Jacobs. While these models and formulas were highly theoretical and complex, Shannon helped Jacobs and others see the eloquence and simplicity of his theories. After thoroughly digesting the theoretical aspects of Shannon’s information theory, Jacobs joined another professor, Jack Wozencraft, to develop a senior-level course on information theory. The goal was to take the sophisticated theory and apply it to practical problems in the real world. While the course quickly became a graduate-level one, it didn’t intimidate the engineering student body—students at all levels filled the seats at the seminars and classes.

Like many other MIT students and faculty, Jacobs took his passion for information theory with him when he visited other universities and events. He also went on to immortalize his work by coauthoring, with Wozencraft, Principles of Communication Engineering in 1965, one of the first textbooks to catapult Shannon’s theories into the world of practical digital communications. Jacobs’s training at MIT and his continual quest for practical applications of information theory set him up to make the transition from the world of academia and abstract mathematics to the realm of practical problem solving, working in companies that were building advanced communications equipment—creating the wireless revolution of the late twentieth century.

© 2005 Dave Mock.
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