Convolutional Coding

Abstract

In convolutional coding, a sequence of data signals enters into the encoder, one bit at a time. The encoder generates n parity bits out of k information bits. The n parity bits, also known as coded information bits, are modulated and transmitted through a channel. At the receiver, the decoder recovers the data by means of code correlation. The ratio k/n is defined as the code rate r, where r = k/n ≤ 1. The code rate is an indication of the amount of redundancy that protects the data. A low value for the code rate relates to more error-correcting ability, but at the cost of increased bandwidth.