Channel Coding

A critical aspect in data transmission is the determination of whether the received data is error-free. To do this some form of channel coding (error protection, or error detection and correction) is utilized. The numbers of errors at the output of the receiver can be reduced by channel coding, which involves adding additional information to the message to increase the receiver’s decision-making ability. This additional, redundant information increases the overhead that is included in the transmission.

The key idea is simple. Rather than transmitting only the original information, the transmitter adds additional bits that are mathematically related to the data. These extra bits do not carry new information, but they provide clues that help the receiver determine whether errors have occurred.

If errors are detected, the receiver may: correct the errors automatically; request retransmission; discard corrupted data; or conceal the errors using other techniques. The specific approach depends on the coding method and application.