It is not a secret to anyone that the transmission of any message may result in distorted information, i.e. erroneous data may appear in the transmitted information. The distortion of information can occur under the influence of many diverse factors, but the most common are the following:
- occurrence in the sending, receiving device or transmitter of malfunctions associated with hardware or software;
- the presence of interference in the connecting communication channel, which may be due to either a malfunction due to damage or a malfunction due to the presence of an external influence (targeted or accidental).
In order to ensure the integrity of the information message during transmission over various communication channels, various technologies are used today, however, noise-resistant coding is the most common, popular, simple and convenient means of protecting data from exposure.
The history of ensuring the safety of information during transmission began in 1948, when the well-known work of K. Shannon, “The Mathematical Theory of Communication,” was published. This article is the primary basis for the formation of such a concept as error-correcting coding, which is understood as coding that provides control over the appearance of errors and, if necessary, their correction.
A stunning conclusion follows from Shannon's article: it is difficult and economically inexpedient to build communication channels that minimize the formation of errors in a message. It is much simpler and more profitable to use various methods of encoding information. At the same time, Shannon did not indicate any specific codes, but only proved their existence.
Types of information coding were actively studied in the fifties of the last century, but the results did not bring any practical effect. The next decade was marked by the finding of a technique that would allow us to create a set of technologies to reduce the likelihood of error formation during message transmission.
The first technology was called block codes and was primarily mathematical in nature. The first error-correcting coding in this form was introduced in the 1950s, when block codes could correct only one error. Of course, such codes are ineffective, and therefore, various studies and developments have been carried out for a long time. As a result, a whole class of codes was created that made it possible to track and correct multiple errors.
Another technology that characterizes error-correcting coding is attempts to comprehend coding and decoding, the appearance and correction of errors from the point of view of probability theory. As a result of lengthy research, a class of non-block codes was created in which convolutional codes were most widely used.
In the seventies of the last century, these two technologies began to be considered in a single key, as a result of which we finally managed to get exactly the codes that Shannon talked about in his article. As a result of a lot of work, two schemes were proposed that formed a family of codes and ensured high levels of ensuring the integrity of the message when it was transmitted through communication channels.
Such was the history of the formation of error-correcting coding. Of course, today a lot of different schemes and concepts are proposed for preserving information during transmission, which differ in functionality, redundancy, reliability, structure, efficiency and other key characteristics.