基於軟性中繼處理的壓縮傳送系統

Abstract

本論文針對二位元均勻分布擬亂訊源，利用低密度奇偶查核碼具體實現合作式通訊的壓縮-傳送機制。合作式通訊系統旨在建構一虛擬的多天線系統，有效運用其空間多樣性以對抗通道雜訊。相較於傳統的放大-傳送及解碼-傳送機制，壓縮-傳送機制是利用中繼端將訊源端傳送的訊號經解碼所得的軟性訊息，進行量化或估計後傳送至目的端。基於低密度奇偶查核碼的良好錯誤更正能力，本篇論文以低密度奇偶查核碼實現壓縮-傳送機制，針對中繼端硬性位元及軟性位元的兩種模式進行模擬分析。實驗結果顯示基於軟性中繼處理的合作式壓縮-傳送機制可有效對抗通道雜訊的干擾。

In this thesis, we study the use of low-density parity check (LDPC) codes for the compress-and-forward systems. Cooperative communication has been shown effective in building a virtual multiple-antenna system which exploits the spatial diversity. Unlike the conventional amplify-and-forward (AF) and decode-and-forward (DF), thecompress-and-forward (CF) uses the relay to perform soft decoding of the received source signals , and then forwards the quantized/estimated soft information to the destination. In this thesis, we exploit the good error-correcting capability of low-density parity check codes for the compress-and-forward scheme in conjunction with the relaying based on hard bits or soft bits. Simulations show that the proposed soft information relaying scheme can outperform traditional CF scheme.