多載波分碼多重進接系統上鏈基頻接收機之設計與模擬

Abstract

未來第四代蜂巢式行動通訊系統需要提供高傳輸速率，多載波分碼多重進接系統結合了分碼多重進接與正交分頻多工的優點，是第四代蜂巢式行動通訊系統熱門的選擇之一。本論文提出一多載波分碼多重進接系統的上鏈基頻接收機架構，接收機設計包含兩部分：通道估計與多用戶偵測器。所有用戶各自傳送一已知的領航訊號供接收機通道估計之用，接收機在進行通道估計之後可以將領航訊號重建並去除其干擾。此外，在每個次載波上採用多層級的平行干擾消除多用戶偵測，每一層級偵測器利用資料決策的結果重建資料訊號，訊號重建的目的在於模擬用戶本身資料訊號對其他用戶造成的干擾，於是，下一層級偵測器根據上一層級偵測器重建的資料訊號消除其他用戶的干擾。我們針對不同的通道環境進行電腦模擬，模擬內容包含比較多載波分碼多重進接與分碼多重進接兩系統單一用戶的接收機效能、探討通道匹配方式對平行干擾消除多用戶偵測之影響並評估通道估計效應等，最後提出結論與未來的研究方向。

The fourth generation cellular mobile communication system in the future needs to provide high data rate transmission. MC-CDMA system combines the advantages of CDMA and OFDM, and it is one of the promising choices for the fourth cellular mobile communication system. In this thesis, we propose an architecture of an uplink baseband receiver for a MC-CDMA system. There are two parts concerning the design of the receiver: channel estimation and multiuser detection. Each user transmits a known pilot signal for the purpose of channel estimation at the receiver. After channel estimation, the pilot signal interference can be reconstructed and removed from the received signal. Besides, we adopt a subcarrier-based multi-stage parallel interference cancellation (PIC) multiuser detection. Each stage detector reconstructs the data signal from the result of data decision, and the aim of data reconstruction is to regenerate the interference caused by the user itself. Then the next stage detector cancels MAI according to the data signal reconstruction from the previous stage detector. Computer simulations are conducted under different channel environment. We also compare the single user receiver performances of an MC-CDMA system and a CDMA system, and discuss the effect of channel matching and channel estimation. Finally, we draw a conclusion and comment on possible future work.