It is not a secret to anyone thatWhen transmitting any message, the information may be distorted, i. e. in the transmitted information, 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 link, 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 integrityinformation message when transmitting through various communication channels, different technologies are used today, but the most common, popular, simple and convenient means of providing data protection from interference is noise-immune coding.
History of information security attransmission began in 1948, when the famous 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 stunning 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 indicate any specific codes, but only proved their existence.
Types of encoding information were actively studied inthe 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 methodology that would allow the creation of a set of technologies to reduce the likelihood of error in the transmission of a message.
The first technology was named blockcodes 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.
Other technology that characterizes the noise-immunecoding, - 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 twotechnology began to be viewed in a single vein, as a result of which it was finally possible to get exactly those codes, which were discussed in his article Shannon. As a result of many works, two schemes were proposed that formed a family of codes and ensured high indicators of ensuring the integrity of the message when it was transmitted through communication channels.
Such was the history of formationnoise-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.