What is channel coding?
channel coding is a technique used in digital communication to ensure transmission with minimal or no errors. Different coding methods that can be used are achieved by connecting other binary digits into transmission. When decoding at the receiving end, the transmission can be checked for errors that may have occurred and in many cases repaired. Other times, the recipient simply asks for transmission.
The idea of coding the channel has been developed due to the inevitable existence of errors on any given type of communication channel. Radio waves, electrical signals and even light waves above the optical channels will have a certain amount of noise on the medium, as well as degradation of the signal that occurs at a certain distance. Given that this is such a common problem in communication, many theories to deal with it have evolved under the industries of applied mathematics, such as theory of information and coding theory.
One commonly used method is called automatic repetition requirement (ARQ), which simply includes a recipient that checks the transmission in terms of errors and the request for repeated transmission if any. This is sometimes referred to as a repair of a back error. On the other hand, the channel coding is a technique of correction forward (FEC). Sending prepares bits for transmission using a special algorithm known as the code correction, which is then decoded at the receiving end. Both methods are also often used in a hybrid way, allowing you to fix small errors in the transmission by channel code, while the main errors require complete gears.
The first channel coding technique was created by a mathematician named Richard Hamming, who developed the so -called hamming code. This was the first correction code of an error forward, which includes the inclusion of another binary digits in transmission called parity bits. The smart calculation of parity bits at the receiving end of the transmission reveals whether there have been errors in the transmission where they are in the bits chain and how to repair them to restore the original transmission.
Hamming code falls into the family of channel coding methods referred to as block codes, many of which have been developed over the years. Block codes usually include collected bits into fixed length blocks, which are then referred to as code words. Each code word will receive the appropriate control bits for decoding the recipient. Block code methods tend to increase the size of transmission due to added bits in the code word, which can affect the channel bandwidth.
Another channel coding method is known as a convolutional code. These methods are much faster and can encode a little current of any length. One commonly used codeTento is called the Viterbi code, created by Italian mathematician Andrew Viterbi. The disadvantage of this method is that with the increasing length of the convolutionary code, the complexity is also complex during decoding. In many cases, convolutional codes are used in combination with block codes in so -called errors correction.