Systems and modules for use with trellis-based decoding

摘要

Systems and modules for use in trellis-based decoding of convolutionally encoded sets of data bits. A first calculation module receives an encoded set of data bits and calculates a signal distance or a measure of the differences between the encoded set and each one of a group of predetermined states, each state being represented by a sequence of data bits. The first calculation module consists of multiple parallel calculation submodules with each submodule being tasked to perform an XOR operation between the encoded set and one of the predetermined states. Multiple parallel second calculation modules each multiple receiving the output of the first calculation module, calculates cumulative signal distances using the output of the first calculation module. Each second calculation module has multiple parallel addition submodules with each addition submodule receiving a specific cumulative signal distance and one of the signal distances calculated by the first calculation. Each second calculation module also includes a decision module which selects the lowest valued cumulative signal distance from the addition submodules in the second calculation module. Each second calculation module outputs its lowest valued cumulative signal distance and this may be used as input to a memory system for storing a database used in further decoding of the encoded data.