From the College of Natural Sciences
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Ronny Hadani Comes in Loud and Clear

Ronny Hadani Comes in Loud and Clear

​Ronny Hadani, associate professor of mathematics in the College of Natural Sciences and co-founder of Cohere Technologies, is developing technologies to make wireless communications faster and more reliable.

Photo by Jeff Wilson

Your company, Cohere Technologies, improves wireless communications. What's the problem your technology solves?

Wireless communication often happens in a very complicated environment. If I'm standing here, talking to you on my cell phone, but you're standing behind a building, whatever I transmit to you is reflected many times. The reflected radio signals interfere with each other. Another complication is that we are moving with respect to one another. That change in velocity causes the Doppler effect, which shifts the frequency of the radio waves. These effects limit how fast we can reliably exchange information.

How did the company come about?

At the end of my PhD, I came to realize that my work related to signal processing, which is a broad topic in engineering that translates nicely to technology. I published a few papers while I was doing my postdoc in Chicago. They were nice, but to contribute something important I needed to collaborate with a partner outside academia who knew about real problems. In 2008, I visited a CEO in California and gave a lecture to his company. We got along and kept each other in mind. After I started at UT, we began to have these Skype conversations. He is a brilliant engineer, but he is also a businessman, a serial entrepreneur. Over several months, these Skype conversations started to shape into something. I didn't know that this would happen; I just wanted to work with someone from the outside, and it was evident that our personalities fit.

"If you give a problem to a mathematician and an engineer, each will see the problem from slightly different angles. Through this angle, over a long period of time, you are able to build something new."

How did you decide on a problem to work on?

The problem gradually emerged out of our conversations. It's very important to understand that all this technology, all of these companies, would never have occurred without collaborations. If I had been alone, nothing would have happened. That's the problem with mathematicians – we're isolated. If you want to solve a problem, you need to collaborate with somebody who understands that there is a problem. We talked about so many things; we talked about radar, we talked about imaging, we talked about these machines in the airport which take an image of you. We went in so many directions, and eventually converged on wireless communication.

What is the solution you're developing?

In most real environments, radio signals get distorted. In order to reconstruct the information, we need to know exactly what happened to the signal and then compensate. In a sense, we "radar" the environment to learn the location and velocity of every reflector. It's done continuously as the conversation is happening and the environment is changing. With those measurements, we can shape the wave patterns to optimize the way they interact with the environment and transmit information more efficiently. The novelty with our technology is the way that we shape those waves.

How effective is your solution?

The implication is very simple: with this technology you can transmit twice as much information as current systems. Maybe, eventually, even five or ten times as much. Bandwidth is like an asset, like a piece of land. One megahertz of wireless bandwidth costs $5 billion. Once you have a piece of land, the next question is what you can build on it. So for wireless operators, this technology allows you to double the amount you can build on a specific piece of land.

How do you hope your work will impact everyday people?

People are talking about all kinds of applications for this boosted capacity. For example, doctors might be able to do robotic surgery from a distance. It's impossible to do that today because wireless communication is not fast enough or reliable enough. You can't send an instruction to make a cut and then have a delay before it actually happens. Advancements like these will change our lives, but they will require a much better infrastructure. We need a much bigger digital highway. So you could say I am in the highway business.

How do you approach your research?

I didn't know anything about communication in the beginning; I didn't know about processing or estimation theory. It's naive to think that the mathematician gets a problem and already has just the right tools to solve it, because that never happens. It takes years to learn and appreciate the problem.

I was able to interpret a large body of knowledge that bright engineers were developing over many, many years. If you give a problem to a mathematician and an engineer, each will see the problem from slightly different angles. Through this angle, over a long period of time, you are able to build something new. It was a dialogue. It emerged from a struggle over a long period of time, and it took a lot of collaborations to shape this.

What inspired you to go into mathematics?

I never dreamed I would become a mathematician. I was building computer games in high school and I wanted to build a game with 3D graphics and I didn't know how to do it. I needed to rotate 3D objects and as it turns out, to do it, you need linear algebra. So I found a book on linear algebra and started to read it. And for some reason, I started to hear what was like this music, and I got fascinated. So I read another book. And another and another. Eventually I applied for a course in the Open University and this translated into me taking a whole degree in mathematics. And after that it was clear to me, okay, this is what I want to do. Computer games no longer interested me. I was completely captivated. From then on, I couldn't think of doing anything else.

What do you love the most about being a mathematician?

First of all, I love the beauty and the simplicity. A lot of people think of mathematics as a complicated subject, but it's not true. It's the simplest subject. It becomes simpler as your understanding gets deeper. As you mature into mathematics, you remember less and less because you can develop everything from scratch. And at the same time, you become stronger because you know how to solve more and more things.

Secondly, I was attracted by its raw power. Mathematics is a hammer that, in the right hands, can break big walls. It's powerful knowledge that allows you to solve non-trivial problems. I felt it as a young man and it always fascinated me.

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Saturday, 23 September 2017

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