Code rate

The code rate or information rate of a forward error correction (FEC) code, for example a convolutional code, states what portion of the total amount of information that is useful (non redundant). The code rate is typically a fractional number. If the code rate is k/n, for every k bits of useful information, the coder generates totally n bits of data, of which n-k are redundant. If R is the net bitrate (useful bitrate), the gross bitrate (raw bitrate) is R•m/n.