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'Source coding': reducing redundancy, eg file compression
'Channel coding': dealing with imperfections of the communication channel, eg error correcting codes. 'Forward error correction' (FEC) means sending signals with some redundancy so that the receiver can correct some errors without any retransmission. A 'systematic code' means a code in which the encoded data embeds the data that you are trying to transmit (eg if you embed the source data and then also some parity bits, as opposed to eg computing a zillion parity bits and then only sending these, and never sending the source data directly).
'Cryptographic coding': transforming the signal to deal with adversaries, eg encryption
'Modulation': varying a periodic carrier wave in some way in order to carry information. Sometimes more generally (and slightly incorrectly) used to refer to the generation of a waveform to transmit a signal.
'Demodulation': The inverse of modulation.
'Modem': A 'MOdulator–DEModulator?' device that can perform both modulation and demodulation.
'Channel capacity': A tight upper bound on the rate at which information can be reliably transmitted over a noisy channel [1].
Some popular (or theoretically important) channel coding/forward error correction techniques are below.
Just transmit each symbol multiple times.
See also N-Modular Redundancy and Triple Modular Redundancy (TMR), which is the corresponding concept in general computing (not just channel coding); TMR means having three different subsystems performing a process and then majority voting the result in order to deal with faults in the subsystems.
A block code which attains the Hamming bound [4].
