But because it was done, it was very important. You just keep changing the product and improving it. So I guess they might be of two sorts: Partly because sequential decoding was a decoding technique for convolutional codes, and in that period people had recognized that convolutional codes were much more powerful than block codes. I didn’t want to build things particularly either, but I was just troubled by the fact that we were putting so much effort into this one problem, the reliable data transmission, when it seemed as if there was much more need for analog communication at the time.
There seems to be more of a need to be successful in lots of different things. What drew you back to it? That close-knit community in fact became a much larger community as time went on. I think the split was similar in the sixties. I forget where I was getting the funding when I was working in the computer field.
Robert G. Gallager — Information Theory Society
It was a very active research topic then. You’ve described what industry needs today, and what industry wants and the sort of grad students they’re looking for. Fields which have only that kind of work going on tend to not attract new people, tend to not attract creative people, and they tend to become more and more stultifying. Whereas in some fields, such as parts of communication technology, cellular telephone systems, and things tbesis that, one doesn’t have to know that much about the field to get into one’s specialty and to operate there.
It’s the kind of channel that you see after you build a modulator and a demodulator and all the other things that you have to build to robegt such a system work. I mean the thing that I was trying to do was to give a guide to how to develop coding systems for, in fact, practical-type channels. The Air Force wanted to see it happen. You remind gal,ager of a question I had when you began.
Robert G. Gallager – Wikipedia
But there is this rich, rich theoretical structure, rich conceptual structure which says how things ought to be done, agllager gives people a clear view of what it is they’re trying to accomplish, and gives a smooth transition from very mathematical approaches to very pragmatic approaches.
It’s just for non-real time data applications that you can use error detection and retransmission. There wasn’t much research going on gallagrr it. So if we can just start with some biographical information, leading up to your training.
Because of this, the place where glalager want to do error correction is down at this physical layer, where you’re dealing with an actual communications link. One curious landmark around’68, I imagine, was a test bed built out at Lincoln Laboratories that made sequential decoders.
I felt some urge to keep up with some of the ideas going on in solid state and things like this. A whole bunch of very good people with an enormous amount of very wonderful effort.
Low-density parity-check codes
It cost a lot of money to build a large computer system; therefore you wanted to have lots of people use it. It was a field where people sort of sent their papers to the other people who were working on similar problems, and things tended to propagate relatively quickly.
I guess the view I’ve come up with–I’m trying to think this through–is that yes, gllager should be interested in real problems.
A lot of those situations are military situations. Then the whole academic enterprise was slanted towards doing more theoretical work, more abstract work.
I think it was not so much that funding became unavailable in the early seventies. You just keep changing the product and improving it.
But I’ve never felt that it really had anything to do with actual computers. You were just saying that there’s a consistency in problems. That’s what scares me. But occasionally, I rober, you worked on specific algorithms for coding, and these seem like different tasks.
Like if you’re trying to get tasks done with a tbesis of different people, you try to organize how that gets done, and you think in very distributive terms then. All go over one line, all go out there, all get mixed up throughout the network. I got into both of them. The university administrators felt it was very important.
But you do all of the error corrections with that sort of in real time. Which is the same as the problem of how to prove that some kind of program is correct. It wasn’t only that we were in an ivory tower, it’s that the rest of the country went along with us in the sense that there weren’t funds for doing other things.
Dave Slepian was teaching about communications theory; there was Bill Bennett teaching about communication also. He’s teaching here part time, too.