ABSTRACT
Error correction techniques based on the addition of redundancy to the original message can be used to control the error rate. The basic ideas of efficient error correction are illustrated in the following example of a Hamming code, a single-error-correcting code belonging to the first class of practical codes invented by Richard Hamming in 1948. Error correction codes can be divided into two different classes: block codes and convolutional codes. Error correcting codes have been applied to a variety of communication systems. Digital data are commonly transmitted between computer terminals, between aircraft, and from spacecraft. Block codes and convolutional codes have similar error-correcting capabilities and the same fundamental limitations. Error detection, which is generally easier to obtain than error correction, is used in applications where it is extremely important to get the correct message or otherwise flag it as unreliable and discard it or ask for retransmission, according to a prescribed protocol as used in automatic-repeat-request systems.
