Cell Phones

Last week, I turned my cell phone off, put it away, and forgot about it. It was a wonderful feeling! I don't like cell phones. I can't really explain why. I put off buying one until about two years ago. I finally broke down and joined the club because I was at a point in my job where people were having a hard time getting in touch with me because I was almost never at my desk. Rather than compromise my work by lack of communication, I relented and bought a phone with a pay-as-you-go plan. I knew I wouldn't use it a lot; I just needed a lifeline to get me in touch with people occasionally.

Well, I think I'm at a point in my job where things have settled down enough that I can put the phone away. So last week, I tried it! And it worked great! It wasn't a decision I made beforehand. I just woke up one morning and decided I was sick of the phone being with me all the time. So I unplugged. This is probably a good time to apologize to any of you who may have tried to call me and couldn't reach me. If it's business, call my office. If it's personal, call me at home. If it's so important that you can't wait until it's convenient for me to respond, you're going to have to find someone else to talk to.

I work in the field of wireless communications. Most of the time, when I tell people that, they say, 'oh, like cell phones?' and I say 'sure' because it's usually not worth explaining to people what I actually do. But even though I don't work directly with cell phones, I think it's funny that I don't like cell phones. I work in a field that helps to enable them, but I don't like the application. I really like the math, the physics, the signal processing, and the communication theory. I also like electromagnetics and wave theory. But I don't like cell phones.

While we're on the subject, let me try to give a brief description of what it is I do professionally. I enjoy developing the theory of new ideas in wireless communications. I do a lot of simulation to test such ideas and I also play with hardware testbeds to implement them in real environments. Though my work is mostly applied to wireless communications, much of it has broader potential application. As far as wireless comm goes, cell phones are one obvious application and the biggest commercial one, but there are others. One domain my group and I are looking at more is wireless sensor networks. Their applications include biological/medical, structural monitoring, agricultural monitoring, and many others.

I have done a lot of work with multiple-input multiple-output (MIMO) communications in which the transmitter and receiver both have more than one antenna. You can get really nice data rates with systems like that if you do it right. There's a lot more you can do there, but that's one of the nicest benefits. I've also done a lot with statistical channel modeling and channel sounding where we send a signal through a channel and, using statistical analysis, try to figure out characteristics of the channel that are important to model. This has applications to tools for validating that a system meets specifications and also for system design. In order to design a waveform and a transmitter/receiver architecture, you need to know what kind of channels your system may be subject to so you can deal with them properly.

Other areas of my research include co-channel interference mitigation and signal detection. Interference can come from trying to put too many users in the same slice of spectrum. Signal detection is trying to find out there's a signal out there and then figuring out where it falls in time, frequency, and other dimensions. Mostly I just love math and signal processing and the area I most often apply those domains to is wireless communications ... and yet I don't like cell phones.

Now that you know far more than you ever wanted to know about my professional interests, I hope you'll understand why, when people ask me what I do, I simply say, 'I do research' and sometimes I'll add, '... in wireless communications.' That's about as far as most people are interested in taking the conversation. And that's ok with me.