METHOD AND APPARATUS FOR DECODING RECURSIVE CONVOLUTIONAL SYMBOLS

摘要

A decoding method and apparatus performs a forward recursion process on recursive convolutionally generated symbols and performs backward recursion on the symbols wherein a next state for the backward recursion process is based on linearly combining both a plurality of bits defining a current state of a backward recursion process and a hypothesized information bit. In one embodiment, a backward state determinator (200) combines all binary bits in a current state backward recursion register (202) to generate a most significant bit (MSB) (210) of a next state backward recursion register (204). To obtain remaining bits of the next state backward recursion register (204), bits (207a - 207n) in the current state backward recursion register (202) are shifted. The shifted bits then serve as the least significant bits (208a - 208n) in the next state backward recursion register (204). Accordingly, a suitable linear combination and bit shifting approach is used to determine the content of a next state backward recursion register (204).