極化碼是第一個能夠達到香農極限的錯誤更正碼。連續消除解碼演算法被提出用於極化碼的解碼，之後翻轉連續消除解碼演算法被提出，藉由找到不可靠的位元和重複解碼來改善極化碼的解碼性能。此外，列表連續消除解碼演算法也被提出，藉由增加更多的儲存空間來保留更多的候選碼字來增加極化碼的解碼性能。然而受限於翻轉連續消除解碼演算法的解碼極限，結合了翻轉連續消除解碼演算法和列表連續消除解碼演算法的優點，翻轉列表連續消除解碼演算法被提出來進一步增進極化碼的解碼效能。

本文提出後處理的列表連續消除解碼演算法。本文不但提出如何在決策端更有效率的決定每個位元的可靠度去判定翻轉位元的順序，並且透過調整通道端不可靠的位元的正負號及大小來改善錯誤率。藉由採用翻轉列表連續消除解碼演算法，可以透過重複解碼找到更多可能的碼字來增進解碼性能。

Polar codes is the first linear block codes which can achieve Shannon capacity. Successive cancellation (SC) decoding was proposed to decode polar codes. Later, SC-Flip decoding was proposed to improve the error rate performance of polar codes by finding unreliable bits and decoding more times to find different codeword. In addition, CRC-aided list successive cancellation (CA-LSC) decoding was proposed to enhance the error rate performance of polar codes by using more storage memory to preserve more candidate codeword. However, the SC-Flip decoding still has its limit on error rate performance. By combining the advantage of SC-Flip decoding and CA-LSC decoding, LSC-Flip decoding was proposed to further improve performance of polar codes.

In this work, we propose a post processing algorithm for CA-LSC decoding to further improve the error rate performance of polar codes. We not only propose a new method to calculate the reliability of each information bit to determine the flipping order for decision part, but also adjust the sign and magnitude value for unreliable channel position according to LLR value of channel to improve the error rate performance. By performing post processing algorithm for CA-LSC decoding on channel and decision part, we can use additional attempts to re-decode to find more possible cnadidate codeword to improve the performance of poalr codes.

Abstract-------------------------------------------------I
中文摘要-------------------------------------------------II
第一章 簡介-----------------------------------------------1
第二章 極化碼與解碼方法的回顧-------------------------------4
第三章 後處理的循環冗餘校驗碼輔助的列表連續消除解碼演算法-----20
第四章 實驗結果-------------------------------------------33
第五章 結論-----------------------------------------------45
參考文獻-------------------------------------------------46

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