渦輪乘積低密度奇偶檢查碼對雷利通道之研究

Abstract

現今的通訊系統以無線通訊為主流，通訊的通道不再是以只有加成性高斯雜訊(AWGN)為主，更有著通道干擾(Interference)。一般通道種類為雷利衰減通道(Rayleigh fading channel)，在本文更討論著不同型態的通道，而設計一套錯誤更正碼來抵抗這些不同的通道型態。所使用的錯誤更正碼為低密度奇偶檢查碼(LDPC)和渦輪乘積碼(Turbo product code)兩者的結合，發現能使訊息傳遞更能抵抗不同型態的通道干擾。 本文的結構敘述如下:第一章介紹低密度奇偶檢查碼(LDPC)如何運作，第二章為乘積碼(product code)的介紹與渦輪乘積碼(Turbo product code)的應用，第三章介紹並且定意所使用通道的模型，第四章為模擬的結果，第五章為結論並且提出未來能走的方向。

Recently, wireless communication systems become popular. Among the dominant factors of affecting system performance, the channel fading effect and noise, usually modeled as additive white Gaussian noise (AWGN), are most common. Rayleigh fading channel is a popular channel model. In this thesis, we investigate different channel models, and design an error correction code to mitigate the channel effect. We use the combination of low-density parity-check code (LDPC) and turbo product code, and we find that it is an effective way to defend the different channel conditions.

This thesis is organized as follows. Chapter 1 introduces the motivation. Chapter 2 introduces the low-density parity-check code (LDPC). Chapter 3 introduces the product code, turbo product code and simulation with the combination of turbo product code and LDPC code. Chapter 4 introduces various channel models. Chapter 5 presents the simulation of our error correction method, and discusses the simulation result. Last, in chapter 6, we summarize this thesis and propose future work directions.