Offset Shuffled Turbo Decoding

[[abstract]]渦輪碼是一個廣泛被使用在各種通訊系統上的高性能錯誤更正碼，也是為第四代行動通訊標準-長期演進（Long Term Evolution, LTE）的關鍵性技術之一。一般而言，渦輪解碼是利用不斷的遞迴解碼來改善錯誤率，但也衍生出因為多次的遞迴造成解碼延遲的問題。洗牌式渦輪解碼器，透過增加交換最新的外部資訊來減少遞迴延遲，但僅適用於兩個元件碼以上的渦輪碼，在傳統渦輪碼上有錯誤率不佳的缺點。針對前述問題，本論文提出一個可以有效降低渦輪解碼延遲的方法。有別於我們提出明確可實施的做法。所提方法，可以利用調整解碼演算法的延遲參數來權衡性能與延解碼遲的表現。模擬的結果顯示，當所提方法的延遲參數在75％碼框延遲時可達到與傳統渦輪解碼器相當的錯誤率表現；且在每次遞迴延遲可以減少25％的解碼延遲。所提方法除了大幅減少解碼時間外，更可將渦輪碼的應用推廣至需要高速解碼的光纖通訊系統之中。[[abstract]]Turbo codes have become an attractive forward error correction scheme for wireless communication systems, it has become standard of LTE (Long Term Evolution, LTE) mobile communications. In general, turbo decoding used iterative decoding process to improve its performance, but large number of iteration will increase decoding delay time. For this problem, we propose a method that reduced turbo decoding delay time, and the complexity lower than decreases code rate. In simulate show, when delay 75%, the performance close to traditions turbo code performance, and delay time can decrease 25% in total iteration. In high speed decoding, we proposed method can reduced many delay times