Hedy Lamarr + Frequency-Hopping Spread Spectrum
Wireless communication technology has a long history dating back to the 19th century with scores upon scores of inventors, engineers and companies contributing to technologies we see today. When looking back to the origins of a specific method known as Frequency-Hopping Spread Spectrum (FHSS) the most famous names may come to mind—Guglielmo Marconi, Nikola Tesla and Jonathan Zenneck. All three of these men are well known for their contributions to industry, science and communication; but there was another major player in the evolution of wireless communication. Her name was Hedy Lamarr.
Before we dive into Hedy’s story, lets first exam what FHSS is and how it is applied. Frequency-Hopping Spread Spectrum is a method of transmitting a radio’s carrier signal between many different frequencies—usually in a rapid succession of “random” sequence. The transmitter and receiver are synchronized to know when to switch frequency and what frequency to switch to for consistent and reliable communication over the air. Switching of frequencies is where the idea of “hopping” derives. This hopping mechanism increases resiliency to interference as well as causing minimal interference for other wireless communications. It is also more difficult to intercept vs. a set frequency. How is this method used today?
The most common application of FHSS is used every day by millions and millions of people—Bluetooth. More specifically Bluetooth uses a variant of FHSS; however, FHSS is the underlying technology behind Bluetooth. Another significant use of FHSS is in military communication as it is resistant to jamming by adversaries. How does Hedy Lamar fit into this story?
Some of the older generations may know of Hedy, but for you younger folks…Hedy Lamar is most widely known as a movie star in Europe and Hollywood during the golden age of film (1930’s – 1950’s). Born in 1914 in Austria, she quickly rose to fame as a movie actress—but always had a passion for inventing and was known quite well as a “tinkerer” by close friend Howard Hughes. Hughes himself was a movie producer and inventor.
During the Second World War, Hedy conjured an idea of using a frequency hopping signal to prevent radio controlled allied torpedoes from being jammed by enemy forces. She recruited a friend and fellow pianist/composer to patent a miniature piano player to synchronize radio signals as they hopped frequencies. Unfortunately, the US military passed on the innovative technology at the time—but it was later rediscovered a decade later and used on naval ships during the Cuban Missile Crisis. Since then, the application of FHSS has increased exponentially for commercial and military applications from Bluetooth to cellular phones to military communications.
For many years her story was widely ignored in regards to her contributions to wireless technologies, but her story is making a comeback. Too often we recognize the great men of history, but that is only half of our collective human experience. Women have played an equally important role in advancing technology. It is important to recognize all contributors to history—especially those who contribute in great measure like Hedy Lamarr. History is what we collectively choose to remember. Let’s make the effort to include everyone in our history and recognize how they helped shape our present world.
Alex Zeltmann is an ABS veteran and a rock star Infrastructure Engineering Manager. With over 10 years of experience in networking technology, he leads ABS’ team of implementation engineers as they integrate the latest technologies for ABS clients.