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Published byBathsheba Holt Modified over 9 years ago
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Block Turbo Decoder Design Hu Dongwei
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Error Correcting Codes Classic Block Codes BCH RS RM Convolutional Codes (Viterbi) Turbo Codes Parallel Concatenated Convolutional Codes Serial Concatenated Block Codes
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Block Turbo Coding
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ML decoding 即寻找一个与接收信号 R 有最小欧氏距离的 码字。
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Problems of ML Decoding 可能的码字个数:26*26=676 需计算这么多欧氏距离,计算量太大
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Chase Algorithm Hard Decided Sequence: Reliability: Step 1: find p least reliable positions.
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Chase Algorithm Step 2:generate test patterns: Step 3: decode the test patterns and form the code set C Step 4: find the minimum distance code D.
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Log likelyhood
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Max-logMAP
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Soft Output In the decoded set C, if we can find a code word that complements with D at the jth bit position and has minimum distance with R Computing the soft output corresponding to the jth bit:
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Soft output If we can not find such a word in C,
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Extrinsic information
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Iterative decoding Column --- row --- column ----- row ----- column …..
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Performance
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