Скачать или смотреть Convolution decoding

Keywords: Trellis diagram, code tree, shift register, constraint length, code rate
The sliding nature of the convolutional codes facilitates trellis decoding using a time-invariant trellis. Time invariant trellis decoding allows convolutional codes to be maximum-likelihood soft-decision decoded with reasonable complexity. Convolutional codes are often described as continuous.
The ability to perform economical maximum-likelihood soft-decision decoding is one of the major benefits of convolutional codes. This is in contrast to classic block codes, which are generally represented by a time-variant trellis and therefore are typically hard-decision decoded. Convolutional codes are often characterized by the base code rate and the depth (or memory) of encoder [n,k.K].