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Interview with Wireless Expert Ted Rappaport

📄 Contents

  1. Interview with Dr. Ted Rappaport of Virginia Tech and Wireless Valley
  2. Interview with Dr. Ted Rappaport of Virginia Tech and Wireless Valley, Continued

Wireless Expert Ted Rappaport answers questions on Wireless LANs, 802.11, MPRG, 3G, and starting startups. Ted is the Chairman of Wireless Valley Communications, Inc..

This interview originally appeared in Spread Sprectrum Scene Online, an information resource devoted to RF, wireless, spread spectrum, and advanced digital design. They offer articles, design tips, and links.

Dr. Rappaport is the author of the book, Wireless Communications (December 2001, Prentice Hall) and Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications (1999, Prentice Hall).
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Dr. Rappaport is recognized internationally as one of the world's leading experts in indoor propagation. He received BSEE, MSEE, and Ph.D. degrees from Purdue University in 1982, 1984, and 1987, respectively. In 1988 he joined Virginia Tech's electrical and computer engineering faculty, where he founded the Mobile & Portable Radio Research Group (MPRG), a university research and teaching center dedicated to the wireless communications field. In 1989, he founded TSR Technologies, Inc., a cellular radio/PCS manufacturing firm that he sold in 1993.

Dr. Rappaport has 22 patents issued or pending and has authored, co-authored or co-edited 17 books and more than 150 technical journal and conference papers in the wireless field. He is series editor for the Prentice Hall Communications Engineering and Emerging Technologies book series, and serves on the editorial board of International Journal of Wireless Information Networks (Plenum Press, NY) and the advisory board of Wireless Communications and Mobile Computing for Wiley InterScience.

His list of awards is impressive, and includes the Marconi Young Science Award in 1990, the NSF Presidential Faculty Fellowship in 1992, the 1999 IEEE Communications Society Stephen O. Rice Prize Paper Award, and the Sarnoff Citation from the Radio Club of America in 2000. He is a Fellow of the IEEE, and is active in the IEEE Communications and Vehicular Technology societies. Dr. Rappaport is also chairman of Wireless Valley Communications, Inc., a microcell and in-building design and management product company. He is a registered professional engineer in the state of Virginia and is a Fellow and past member of the board of directors of the Radio Club of America. He has consulted for over 25 multinational corporations and has served the International Telecommunication Union as a consultant for emerging nations.

Interview with Dr. Ted Rappaport of Virginia Tech and Wireless Valley

Question: Dr. Rappaport, thank you for talking with us today. Before we get into some of the more technical questions, would you tell us how you got interested in Electronic Engineering? And was RF your initial interest, or did you start with some other aspect of electronics and "fall into" RF?

Answer: My grandfather had this really old Philco shortwave radio, a 1926 model that was mounted on the wall in his home in Brooklyn, New York. We went there when I was 5 years old, and he spent hours with me tuning around listening to Morse Code and Ship to Shore. Ever since then I've been fascinated by wireless and with radio. My grandfather has long since passed away, and my grandmother gave me that radio. My wife, for an anniversary present, had it all restored to its original condition, and I have it in my living room. It still works, and I listen to it every now and then.

So, that's how I got my start in radio. I got my amateur radio license when I was 14, and my extra class license when I was 16 (call sign N9NB). I was really into it! I always knew from the time I was 5 that I wanted to be in wireless.

I went to Purdue University, because I grew up in Indiana, and Purdue was the in-state engineering school. I got to Purdue at a really neat time — I started college in 1978 — and in the late 70s, you remember, 2-meter radios were the big craze and it was before the cellular industry. At Purdue there were several professors — and one in particular, George Cooper — who were early pioneers of cellular. In fact, George Cooper wrote the first paper in the world suggesting frequency hopping spread spectrum for mobile radio. It was co-authored by a student named Ray Nettleton, and when it was published in 1972, it was very controversial. At that time, the FCC was moving towards making a cellular radio service, and a lot of people in the industry were scared that this paper might undermine the standards activities that were going on at that time. Actually, the paper suggested the Hadamard codes and the Walsh functions and ideas that were eventually used in Qualcomm's IS95.

So, Purdue had a rich history in mobile radio and radar, and when I started grad school I was lucky to take courses from George Cooper and learn about the cellular industry before it was on its feet in the US.

My PhD thesis in 1985-1987 was the first broadband wireless thesis looking at 100 megabit per second data rates inside factory buildings — this was before the internet. Indoor propagation just hadn't been looked at much up until then. In my research, I used a very broad 200 MHz bandwidth sounder to study multipath and propagation around the buildings. My thesis was published and generated some interest in the wireless community — it was the time when companies like Lucent, AT&T, Bell Labs and British Telecom were just starting to look at broadband wireless. GSM was just a twinkle in people's eyes back then. I wanted to be a professor because I knew there would be a huge demand for students and for basic knowledge that would make this wireless revolution happen. I believe that someday we will have wireless everywhere for mobile communications, and have always believed this. Virginia Tech gobbled me up and gave me the ball to run with here.

Question: Tell us about how you started the Mobile Portable Radio Research Group at Virginia Tech.

Answer: I landed at Virginia Tech as an Assistant Professor in 1988. At that time, it was very hard to get government funding for wireless communications. In fact, wireless as a term wasn't even used — it died in the 40's and came back again in the early 90s — they called it mobile radio instead of wireless. I had this vision of a research program that would teach students and develop new technologies for the wireless industry, so I took my vision to the companies of the U.S. I spent a year and a half talking to industry putting this vision together, and our early sponsors, who first came on in 1990, included AT&T, Motorola, Bellsouth, Southwestern Bell, and FBI, and it's grown rapidly since then.

And that's how MPRG started. It was one of the first wireless research programs in the country. David Goodman at Rutgers started WINLAB a bit before I started MPRG, and over the years our research and our students have spun out all over the wireless industry. From MPRG, we've graduated over 250 graduate students and 50 undergrads who have known a lot about wireless and have gone on to become some of the ground floor people at Qualcomm, Metawave, WFI, and many other companies as well.

Question: What sort of research projects do you currently have underway at MPRG?

Answer: Today we're doing a lot of varied work. First of all, we're looking at propagation issues for very high frequency, high bandwidth communications, such as for fixed wireless access systems at 38 and 60 GHz. We're one of the few universities in the world that actually has 60 GHz propagation measurement communications equipment.

We're also developing new types of antennas — smart antennas with adaptive array algorithms and multi-user detection techniques for CDMA. 

We're developing new error control coding techniques that can be applied to wideband CDMA communications.

And we're also doing wireless system design research on how to deploy a multi-user ad hoc network like a wireless LAN — how to predict throughput and coverage, and packet latency through some basic physical parameters in the channel.

Editor's note

also click here to go to the MPRG page with information on Dr. Rappaport's current research interests and projects, and links to research results.

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