| 摘要 |
PROBLEM TO BE SOLVED: To prevent deterioration in processing performance due to the number of times of memory accesses to a path memory in the case of trace-back processing and to reduce a capacity of the path memory. SOLUTION: An ACS processing section 13 estimates a most probable path in each state at a present time on the basis of a path metric calculated by branch metric processing for each unit time and a path metric up to a preceding time stored in either of a couple of path metric buffers 18a, 18b, rearranges maximum likelihood decoding information up to the preceding time stored either of a couple of data buffers 17a, 17b on the basis of the estimated path and writes the rearranged information to the other, updates the path metric stored in either of a couple of the path metric buffers 18a, 18b and writes the updated path metric to the other. A trace back processing section 14 retrieves decoded data on the basis of the path metric stored up to a present time stored in the path metric buffers 18a, 18b and the maximum likelihood decoding information up to the present time stored in the data buffers 17a, 17b.
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