在時變衰減通道下的結合通道估測與信號偵測演算法和低密度同位元檢查碼之遞迴系統

Abstract

一個在雷利衰減通道下使用非同調低密度同位元解碼的結合通道估測,信號偵測與通道解碼之 遞迴式接收器系統在本研究中被提出. 本遞迴式系統之非同調演算法可以在不使用任何領航信號與訓練信號的情況下達成通道估測與信號偵測的實現. 此系統之效能將會在平緩衰減通道與頻率選擇性衰減通道下被研究討論. 在平緩衰減通道下, 模擬結果顯示使用本非同調演算法之遞迴式系統的效能與假設理想通道已知之遞迴式系統的效能約僅較差0.5分貝. 此結果與使用外部資訊轉移曲線分析之結果一致. 然而在多重衰減的通道下, 使用本演算法與假設理想通道已知的遞迴式系統之效能比仍有不小的差距, 需要未來更近一步的研究討論.

An iterative receiver structure for joint channel estimation, symbol detection and channel decoding is proposed for the non-coherent decoding of the low-density parity check code in Rayleigh fading channels. Performance of the proposed algorithm is studied for both the flat and frequency-selective fading channels without using any pilot or training symbol. In flat fading channels, simulation results show that the performance of the non-coherent algorithm is only half decibel inferior to the coherent one, which matches the analysis using extrinsic information transfer chart, while in multiple fading channels, the performance gap against the coherent one is still large, which requires further investigations.