- 學位論文
改良式LS領導式通道估測應用在基於OFDM之MC-CDMA系統於UWB通道下之研究
An Improved LS Pilot Channel Estimation Method in MC-OFDM-CDMA System over the UWB Channel
摘要
本論文主要為探討在UWB通道下，使用改良式LS領導式通道估測方法於基於OFDM之MC-CDMA系統(MC-OFDM-CDMA)的效能分析，並與此方法在OFDM系統之效能做比較。改良式LS領導式通道估測被提出應用於UWB通道下之OFDM系統，其方法主要是加入判斷通道變換點的規則，以適應室內通道快速變化。MC-OFDM-CDMA系統則結合了OFDM系統及MC-CDMA系統的優點，具有多工的特型，可讓多使用者在同一頻帶中，同時傳輸訊號。在本論文中，將探討MC-OFDM-CDMA系統於UWB通道下，使用改良式LS領導式通道估測法，以領導符碼頻帶作為主要通道估測方式，用電腦模擬與理論最佳值作比較，以其得到最佳使用方式，同時也與OFDM系統之效能作比較。此外，本論文也將探討使用此系統於多使用者上鏈通道及下鏈通道之效能分析。
並列摘要
This thesis mainly researches into the performance of the improved LS channel estimation method in the OFDM based MC-CDMA system over the UWB channels and compares our results with the performance of this method in the OFDM system. An improved LS method that was proposed to apply in OFDM systems over the UWB channel can adapt to the indoor fast-varying channel by utilizing the addition rules in judging the changing points of the channel. The MC-OFDM-CDMA system shares the benefits of both OFDM and MC-CDMA systems and has the property of multiple access that allows multi-user transmitting signals in the same band. In this thesis, we research into the improved LS method in MC-OFDM-CDMA systems by using the pilot band to do channel estimation over the UWB channel. We compare simulation values with the theoretical optimal values to find the best solution of this method. And then we compare our results with the performance of this method in the OFDM system. In the thesis, we also research into the performance of this method in the MC-OFDM-CDMA system for both multi-user uplink and downlink channels.