Computer Communication Theory & Information Theory - A name change?

[Lou Arnold]

TL;DR Summary

Communications Theory Renamed to Information Theory? And a good book for Communication channel characterizations?

Retired computer engineer here. I have a professor's unpublished notes, back to 1974 entitled "Computer Communication Theory" that containing a great deal of probability, random variables, and Markov chain sections as well as old Bell Systems Journal notes about hardware and protocols. Has this been renamed to Information Theory and cover roughly the same mathematics?

Also, I'm looking for a book about Communications Theory (graduate level) that is largely mathematical covering channel characterizations, etc. Any one know of a good one?

Thanks,
Lou

 

[berkeman]

Here are a couple textbooks that I used in EE grad school -- I don't know if they are what you are looking for.

https://www.amazon.com/Principles-C...n-Wozencraft/dp/0881335541/?tag=pfamazon01-20

https://www.amazon.com/Introduction...ell-Stremler/dp/0201184982/?tag=pfamazon01-20

 

[jedishrfu]

Are you looking for foundational stuff like Claude Shannon or more like communication protocols.

Years ago I took a communications protocols course at work. The instructor had a lot of stories surrounding the design and implementation of various popular communications protocols.

1) an systems guy had a lot of terminals that didn't seem to connect to his modems. He figured out that if a particular line was high then they would start to work so his solution was to add a 9v battery to each terminal to make the line high so they would work. The problem he now had was changing out the batteries every few months on a hundred or so terminals. The instructor chuckled and said he didn't have the heart to tell the hapless engineer that there would have been a dip switch on the terminal so make that line high as an option.

2) Another protocol designer assigned character values to strings of zeros and ones based on usage. As an example the letters ETAON are the five most commonly used in English words so he'd make E=01 T=011 A=0111 ... Sadly his protocol took way longer to send streams of data. It was later tracked down to rubouts being sent and he had given them the code 01111111111.... 127 ones. The rubouts were spacng between the terminal screens being sent over the comm line and they were by far the most common character.

3) The last story I recall was a means to trick a bank into sending money by hacking into their network and slowly sending messages with broken CRC checks. Initially they would be flagged as bad and rejected but as more and more were sent and getting rejected an operator might step in and let them pass thinking there's an issue with the CRC bits and bingo you slip in your money transfer to a swiss bank and you'e made for life until the authorities catch up and you're in for life.

His theme was to each the protocol and then show its weaknesses with these humorous stories and anecdotes.

I wish I could remember his name but it was in the early 1980s when I was getting acquainted with the Honeywell Level 6 mini-computer when mini meant the size of several large book shelves stacked together.

 

[jedishrfu]

As an aside here's a list of interesting protocols:

https://www.elprocus.com/communication-protocols/