Patent ID: 7178090
Filing Date: 2007-02-13
Classification: H03M

Abstract:
1. An error correction code decoding apparatus for performing soft-output generating processing by executing forward processing and backward processing on a code trellis, based on received data and a priori information and by exploiting the values as calculated by said forward processing and backward processing, said apparatus comprising: a memory for storing received data; a memory for storing a priori information; a forward Processing module for performing forward processing; a soft-output generating module for generating soft-output; and a plurality of backward processing modules executing backward processing at different time points on the code trellis, wherein said backward processing module comprises updating, means for updating a backward value, storage, means for storing received data, storage means for storing a priori information and storage means, for storing the backward value; wherein input to said backward processing module is either said received data and said a priori information read in from said memory, or received data and a priori information stored in said received data storage means and said a priori information storage means, respectively, in another one of backward processing modules, said other one being predetermined per each of the backward processing modules; wherein said backward value storage means holds backward value generated value generated by said backward processing; wherein said backward value updating means updates the backward value, stored in said backward value storage means, using the received data and the a priori information as an input to said backward processing module; and wherein the received data and the a priori information are read in periodically from a memory in a reversed sequence; the received data and the a priori information read in from said memory, are provided as inputs to a selected backward processing module; and wherein the selected backward processing module receiving the received data and the a priori information read in from said memory as inputs is changed to another backward processing module for each period.