| 摘要 |
PROBLEM TO BE SOLVED: To calculate likelihood information at high speed while suppressing increase in a throughput and circuit scale. SOLUTION: When operating a backward probability in a backward probability operating part 112, while one processing system calculates a backward probabilityβ<SB>k</SB>from a backward probabilityβ<SB>k+2</SB>, the other processing system calculates a backward probabilityβ<SB>k-1</SB>from a backward probabilityβ<SB>k+1</SB>. In the case of k=1, specifically, a backward probabilityβ<SB>1</SB>and a backward probabilityβ<SB>0</SB>are parallelly calculated by the two processing systems. The calculated backward probabilities are stored in a storage part 114 in the unit of a window. In a forward probability calculating part 113, similarly to the backward probabilities, a forward probabilityα<SB>k</SB>and a forward probabilityα<SB>k+1</SB>are also parallelly calculated by two processing systems. When the forward probabilities are calculated, a likelihood operating part 115 uses the forward probabilities and the backward probabilities stored in the storage part 114 to calculate likelihood information. COPYRIGHT: (C)2005,JPO&NCIPI
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