Noiseless coding: how did it all start?

It is not a secret to anyone that, when transmitting any message, information may be distorted, i. E. In the information being transmitted, erroneous data may appear. Distortion of information can occur under the influence of a variety of very diverse factors, but the most common are the following:

- occurrence in the sending, receiving device or transmitter of problems related to the hardware or software part;

- the presence of interference in the communication channel, which may be due to both a malfunction due to damage and a malfunction due to the presence of an external influence (purposeful or accidental).

In order to ensure the integrity of the information message when transmitting through different communication channels, different technologies are used today, however, the most common, popular, simple and convenient means of protecting data from interference is noise-immune coding.

The history of ensuring the safety of information during transmission began in 1948, when the well-known work of K. Shannon "Mathematical Theory of Communication" was published. It is this article that is the primary basis for the formation of such a concept as noise-immune coding, which means coding, which provides control over the occurrence of errors and, if necessary, their correction.

From the article Shannon follows a staggering conclusion: it is difficult and economically inexpedient to build communication channels that minimize the formation of errors in the message. It is much easier and more profitable to apply various methods of encoding information. At the same time, Shannon did not specify any specific codes, but only proved their existence.

Types of encoding information were actively studied in the fifties of the last century, but the results obtained did not bring any practical effect. The next decade was marked by the discovery of a technique that would allow the creation of a set of technologies to reduce the likelihood of an error in the transmission of a message.

The first technology received the names of block codes and was mostly of a mathematical nature. For the first time, noise-immune encoding in this form was introduced in the 1950s, when block codes could correct only one error. Of course, such codes are ineffective, and therefore for a long time, various studies and developments were carried out. As a result, a whole class of codes was created, which made it possible to track and correct multiple errors.

Another technology that characterizes noise-immune 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 studies, a class of nonblock codes was created, in which convolutional codes were most widely used.

In the seventies of the last century, these two technologies began to be viewed in a single vein, as a result of which it was finally possible to get exactly the codes that were mentioned in Shannon's article. As a result of many works, two schemes were proposed that formed a family of codes and provided high indicators of ensuring the integrity of the message when it was transmitted through communication channels.

Such was the history of the formation of noise-immune coding. Of course, today many different schemes and concepts for the preservation of information in transmission are proposed, which differ in function, redundancy, reliability, structure, efficiency and other key characteristics.