基於錯誤更正碼的多路存取設計

Abstract

在本篇論文中我們主要探討三個主題。前面兩個主題是有關交織多工接取系 統，第三個主題是有關在實體層網路編碼的映射方法。首先我們提出一個新的 ESE 演算法，這個演算法可讓交織多工接取系統處理非格雷(Gray)映射的調變。 利用交織多工接取系統的迭代解碼特性，非格雷映射可以提升系統的效能。接 下來我們討論交織多工接取系統中通道估計的問題。利用交織多工接取多層傳 輸的特性，將pilot 訊號嵌入在資料訊號中，並延伸ESE 檢測訊號的方法來做 通道估計。在此方法中我們只須以少量的傳輸能量分給pilot 做訊號檢測，就 可達到最佳的效能。另外，此檢測器可以達到逼近CRLB 的效能。最後在實體層 網路編碼的主題中，我們提出一個新的映射方法用於Two-way Relay 通道。此 演算法基於MIMO 線性檢測，產生一個類似QAM 形狀的星座圖(constellation)， 不僅方便做分析運算，也可得到更佳的效能。

In this thesis we discuss three algorithms for multiple-access communications. The first two are under IDMA context, and the third one is under physical-layer network coding (PNC) systems. First, we propose a new ESE algorithm which can deal with modulations with non-Gray labelling. Better performance can be obtained by leveraging its iterative decoding nature with non-Gray labelling. Second, we extend IDMA principle to channel estimation in IDMA systems. A similar Gaussian approach from ESE is adopted. Only small amount of pilot power is need to obtain the best-achievable performance. Also, it also shows a near CRLB (Cramer-Rao Lower Bound) performance. Third, in physical-layer network coding (PNC) context, we propose a new mapping scheme for two-way relay channels. Based on MIMO linear detection, the mapping scheme has a QAM-like constellation, which is not only easy for analysis and has better performance that other sum/difference scheme.