多天線正交分頻多工系統之頻率補償與資料估測

Abstract

本研究主要探討了高速無線通訊系統中的多通道路逕干擾及時變通道效應。在超高速通訊環境下，多路徑通道造成的碼間干擾(Inter-Symbol Interference)和都普勒飄移產生的載波間干擾(Inter-Carrier Interference)對多天線系統(Multiple antenna system)和正交分頻多工(Orthogonal Frequency-Division Multiplexing)系統的效能表現有著嚴重的影響。這篇論文除了針對前述兩個傳輸技術作深入的探討，並研究了多用戶(Multiple User)多天線系統下的下行廣播通道(Downlink Broadcasting Channel)之傳送端前置訊號處理(Preprocessing)和整合式的多重輸出多重輸入正交分頻多工(MIMO-OFDM)系統的通道估測和頻率飄移問題。 研究方法主要經由相關文獻的回顧，再利用統計和訊號處理技巧對上述問題提出可能的解決方法並以電腦模擬來驗證方法的優越性。

This research studies the multi-path interference and time varying channel effect due to very high mobility terminals and provides possible solutions. The critical issues in very high mobility wireless communications are inter-symbol interference (ISI) due to multi-path fading and inter-carrier interference (ICI) due to oscillator mismatch and high Doppler shift. Two transmission techniques (orthogonal frequency division multiplexing, OFDM and multiple-input multiple-output, MIMO) are considered in this thesis. In addition to discussing the above mentioned techniques individually, we also study the multi-user MIMO preprocessing for broadcasting channels (BCs) and the MIMO-OFDM technique, which attracts much attention in both academic and industry. Through surveying literatures, we use statistical and signal processing techniques to derive our algorithms and demonstrate our superiorities by computer simulations.