第四代行動通訊渦輪碼內之二階重排多項式交織器

QPP Interleaver of Turbo Code in 3GPP Long Term Evolution

李順吉(Shuenn-Ji Lee)

《電腦與通訊》 126期 (2008/12) Pp. 55-59

https://doi.org/10.29917/CCLTJ.200812.0009

摘要

第四代行動通訊(3GPP LTE)於2007年初確定以QPP(Quadratic Permutation Polynomial)交織器(Interleaver)取代第三代行動通訊中實體層渦輪碼(Turbo code)的交織器，藉以大幅改善解碼器的解碼速度。QPP交織器除了具有記憶體無競爭(Contention Free)的優點外，在硬體的複雜度及解碼性能上皆有不錯的表現。QPP交織器使得渦輪碼很容易地避免在計算最大事後機率(MAP)之後記憶體寫入碰撞的問題，同時，利用多個移動視窗(Sliding Window)來達成平行運算(Parallelism)以加快解碼器的運算速度。本文首先介紹QPP交織器的原理，並推演出低複雜度的硬體電路設計及LTE渦輪碼內對QPP交織器的相關規範。

關鍵字

二階重排多項式 ； 渦輪碼 ； 長期演進

並列摘要

The QPP (Quadratic Permutation Polynomial) interleaver is finally voted as the 3GPP LTE Turbo interleaver in 2007 for its dramatic improvement of decoding speed. QPP interleaver has the advantages of memory contention free, low complexity, and decoding performance. QPP interleaver makes it easy to avoid the memory writing contention problem after computing the MAP (Maximum a posteriori probability) with parallel sliding windows. This article describes the QPP algorithm and derives low complexity hardware reference design. The QPP interleaver in LTE Turbo encoder will also be introduced.

並列關鍵字

Quadratic Permutation Polynomial ； Turbo code ； Long Term Evolution