里德所羅門碼之信念傳遞解碼演算法研究

Abstract

里德所羅門碼 (Reed-Solomon codes) 目前已被使用於許多先進的通訊和儲存系統上。眾所皆知，里德所羅門碼的軟式決策解碼相較於傳統的硬式決策解碼能夠提供明顯的效能改善，但由於其軟式決策解碼的高複雜度，目前大部分的系統仍然使用傳統的硬式決策解碼器。Jiang 和 Narayanan 於2006年提出了一種利用適應性校驗矩陣，對里德所羅門碼進行軟式輸出輸入解碼的演算法 (JN演算法)。JN演算法能夠避免校驗節點飽和化以及低信任度位置之錯誤傳遞等問題，然而其潛在的問題在於過度信任高信任度位置的訊息。於本篇論文中，我們首先將討論造成JN演算法解碼失敗的因素，並提出適當的演算法來避免JN演算法中高信任度位置錯誤所造成的影響，並增進其解碼效能。

Recently, Reed-Solomon (RS) codes have been used in many state-of-the art communication and recording systems. It is known that soft-decision decoding (SDD) of RS codes provides significant performance gain over hard decision decoding (HDD), but most systems still are based on HDD because of the high complexity of SDD. In 2006, Jiang and Narayanan presented an iterative soft-in soft-out decoding algorithm of RS codes by adapting the parity check matrix. JN algorithm can avoid the problem of check node saturation and the error propagation from the least reliable positions, but the drawback of JN algorithm is to over believe the message from the most reliable positions. In this thesis, we first discuss the cause of decoding failure in traditional JN algorithm. Based on our discussion, we present a proposed algorithm to avoid the influence of the high reliable errors in JN algorithm and improve the decoding performance.