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Block Turbo Decoder Design Hu Dongwei. Error Correcting Codes Classic Block Codes BCH RS RM Convolutional Codes (Viterbi) Turbo Codes Parallel Concatenated.

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Presentation on theme: "Block Turbo Decoder Design Hu Dongwei. Error Correcting Codes Classic Block Codes BCH RS RM Convolutional Codes (Viterbi) Turbo Codes Parallel Concatenated."— Presentation transcript:

1 Block Turbo Decoder Design Hu Dongwei

2 Error Correcting Codes Classic Block Codes BCH RS RM Convolutional Codes (Viterbi) Turbo Codes Parallel Concatenated Convolutional Codes Serial Concatenated Block Codes

3 Block Turbo Coding

4 ML decoding 即寻找一个与接收信号 R 有最小欧氏距离的 码字。

5 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

6 Chase Algorithm Hard Decided Sequence: Reliability: Step 1: find p least reliable positions.

7 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.

8 Log likelyhood

9 Max-logMAP

10 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:

11 Soft output If we can not find such a word in C,

12 Extrinsic information

13 Iterative decoding Column ---  row ---  column -----  row -----  column …..

14 Performance


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