If you send me something, I find out that something is wrong with it, then I have to tell you to send it over again. You remind me of a question I had when you began. Then the whole academic enterprise was slanted towards doing more theoretical work, more abstract work. Then, by the early seventies, people were starting to think that information theory had worked itself through all its interesting problems. Back then there was hardly any variation in what electrical engineers took.
Partly people at places like Bell Labs and large industrial research laboratories. That’s one example of this kind of thing. The only time when you have to receive things right the first time, is sometimes in situations where you only have communication in one direction. The developments in architecture come from people who build systems. Gallager Leo Esaki Amos E.
The random-access aspects of it are probably not going to be the important aspects.
Explained: Gallager codes
If you made it complicated enough, you could reach capacity — but you would probably never decode it. I don’t know why that always happens, but it always has. It was relatively low speed; I forget what it was.
I wonder if you can tell me about the merging of these two areas, you know, computer research and communication. By or so I was starting to work in computer science for the most part, so I would go back and forth between communication and computers, partly because I was listening to other people too much.
Every once in a while you see things starting to grow up which might provide a liaison, but the computer field changes so fast–I mean, the technology changes so fast–that somehow the understanding never seems to have a chance to catch up.
I got into both of them. There was lots of student interest. Because of this, the place where you want to do error correction is down at this physical layer, where you’re dealing with an actual communications link.
All of the channels are operating at a fixed rate. The courses I was taking that were most interesting were the ones in information thesie and various related subjects. It doesn’t work for video. You were discussing the funding, the military funding, that was available in the beginning for communication work.
Low Density Parity Check Codes
And to me the point of theory is to see a picture, is be able to visualize what’s important in a problem. Channel codingExplainedInformation theoryLow-density parity check codesTurbo codes. In another five years, who knows what there will be.
It was something which was interesting. That rate varied according to the transmission power thesia noise characteristics of a channel, but in practical communications systems, it might be only halfway to the Shannon limit.
These are the problems you can work out. I think at that point I was just trying to learn what was going on there.
Robert G. Gallager — Information Theory Society
The beginnings of computer science were going on around here, the beginnings of AI, some of the beginnings of what we now call communications biophysics, which is the thing which has grown into pphd communication and things like this: I had very little intention of having an academic career at that time.
It seemed that all the best graduate students were drawn to this one area. Since longer codes take longer to send, a minimum code length implied a maximum transmission rate — the Shannon gsllager. Retrieved from ” https: This robot helps you lift objects — by looking at your biceps MIT and U.
Message passing decoders are suboptimal in contrast, gallaged e. There was a Russian journal which I tried to keep up with because the Russians were doing a lot of interesting work on information theory in those days.
Didn’t Bell begin using pulse-code modulation in ’61 or the early sixties? Gallager consulted for Melpar as a graduate student, and for Codex Corporation when since was founded in Many of them have very little impact.
You said that, say, inright around that time, many people working in communications fled, and got involved in computers. And for a number of years–probably six or eight years–they were building coding devices, trying to sell them. We were applying both communication ideas and control ideas gallage big systems such as military command and control. You were alluding to the introduction of data communication, the first important application phdd all this work that had been done.