An engineering professor tackles big problems—like attracting more women to her field and transferring mountains of data through the air.
Imagine replacing your Internet router at home with a lamp. Instead of radio frequencies, data would zip between your laptop and any source of illumination at the speed of, well, light.
|New adventures in wi-li: Sarah Kate Wilson. Photo by Charles Barry|
Sarah Kate Wilson has spent her career devising ways to send heaps of ones and zeroes through the air. She contributed to LTE (short for long-term evolution) research, which is widely known as 4G and has quickly become standard for high-speed wireless communication between mobile devices and data terminals.
But one of the “fun problems” that has drawn more of her attention of late is optical wireless—the use of LED lights to send information by blinking at nanosecond speed. While this flickering would be too quick for the human eye to perceive, a computer could decode these blinks. Unlike Wi-Fi, “Wi-Li” would only extend as far as the light reached, which makes it much more secure. Also, lighting is ubiquitous in buildings, making the use of this necessity for data transmission a sustainable two-for-one deal.
Wilson is quick to note that Wi-Li has been under consideration since the 1980s. It was initially rejected because radio seemed more practical, and radio could handle the speed requirements. Now with streaming movies, high-res photos, and all the other strains placed on data networks—plus improvements in devices like LEDs and detectors—optical wireless is getting another look.
"You'll never get in."
When she explains her research, Wilson’s hands trace the undulating shape of radio waves, and her eyes light up behind her round glasses. She is an animated speaker, quick to smile, and eager to lead someone, who might be well over his head, into the wonkiest areas of her research. In the way that the best teachers do, she exudes an It’s OK, you got this disposition.
What exactly are “fun problems”?
“For me, that means getting lost in the math and equations. A fun problem is a lot like a puzzle.”
For Wilson, this was the initial appeal of engineering. As an undergrad at Bryn Mawr College, she found herself most looking forward to her math homework. The summer after she graduated, Wilson sold shoes. That job ended as soon as a classmate told Wilson she had an in for a computer programming job.
Wilson had never touched a punch card before accepting the job, but she found she had a knack for the logic behind programming. A couple years after she moved to Palo Alto—to excise the long-distance aspect of a relationship with “a wonderful guy who is now my husband”—she took another leap, into the graduate electrical engineering program at Stanford.
A colleague where she worked at SRI told her, “ 'Don’t bother applying. I didn’t get in and I went to Berkeley. You went to a school I’ve never heard of.' ” Wilson remembers thinking, “That was all the motivation I needed.” At Stanford, Wilson was often the only woman in her classes. She recalls feelings of doubt that would wash over her. “Making mistakes is a big part of engineering.” She also says, “I had a lot of nice guy mentors. But there were some not-so-nice guys as well.”
This experience greatly influenced an idea she still champions today—the need for more women engineers. This year she helped organize the first Women’s Workshop on Communications and Signal Processing. Partially funded by the Institute of Electrical and Electronics Engineers, the meeting addressed the underrepresentation of women in senior leadership positions in engineering.
Attracting women to the field will be just as important as any technological break-throughs for engineering, Wilson says.
This is an important step for Wilson. If more students see women teaching classes, then the idea of entering the field becomes less daunting to women students. How important is this? Attracting women to the field will be just as important as any technological breakthroughs for engineering, she says.
“First, there’s the practical benefit: We need more engineers, period. And this would expand the pool of potential engineers.”
Wilson also points to studies that show differences in problem-solving among male and female engineers. One particular study looked at the differences in playgrounds designed by male and female students. While many of the playgrounds shared common features—slides, monkey bars—there were areas where the designs did not overlap.
“If you added all those ideas together, you end up with a great playground,” she says.
The search for Godzilla
This year, Wilson will be leading a pair of senior engineering students on a search for Godzilla. Inside her office.
While this isn’t the skyscraper-sized lizard, Wilson is talking about an equally disruptive force when it comes to optical wireless. This Godzilla comes in the form of ambient light: If Wilson were to replace her fluorescent lighting with the rapidly blinking LEDs in order to transmit data to her computer, how many other light sources would this system compete with?
Her students will be charged with “finding Godzilla” this year so that Wilson will know exactly what she’s up against in order to make optical wireless work. Derrick Breska ’13 and Brian Gallagher-Howard ’12 will be using silicon detectors that measure light intensity to study signal-to-noise ratio, signal-to-interference ratio, and dispersion effects of optical lighting for communications. Then with that data in hand, the fun is sure to begin.