在現今的生活中，由於數位家庭的崛起，造成電腦、家電廠商無不爭相投入搶攻家庭娛樂結合數位生活這塊市場大餅，全力促使自家產品成為消費者家中的核心「平台」。由於傳輸高畫質的影音服務需要極高的傳輸率(gigabit)，以目前已普及的無線通訊規格並無法支援，所以還是以有線(HDMI)的為主。為了支援這些服務，各無線通訊標準無不朝著高傳輸率來發展，希望能以無線取代有線，透過無線通訊打破空間的規範，使得在家裡的任何地方都能享受到數位生活的方便，並美化家庭的環境。 本論文在於實現無線傳輸模組，基於IEEE 802.11n的系統上來訂立一個新規格來達到傳送高畫質影像的速度需求。此無線通訊基頻收發機將以多輸入多輸出之正交分頻多工(MIMO-OFDM)來實現，操作在lower UNII band，最多使用160MHz的頻寬，再搭配四根傳輸天線及四根接收天線的傳輸率最高可達2.5Gbps。發送端的部分會有256點及512點前置符元的設計，此設計有考量到PAPR和使接收段的訊號偵測及同步的部分易於達成。接收端的部分則有三個主要的任務，粗略同步、殘餘CFO估測及補償還有通道估測與多輸入多輸出偵測。粗略同步在於得到正確的符元邊界以得到精確的FFT的window還有CFO粗估。在訊號進入頻域後繼續的追蹤殘餘的CFO並補償，補償完後就可以開始偵測訊號以重新取回資料。以上的任務在系統模擬的部分均可得到我們所提出的方法對於整體效能有大幅度的提升。This thesis presents a MIMO-OFDM baseband transceiver design for indoor gigabit wireless communication systems. The proposed system uses 5 GHz carrier frequency with bandwidth up to 160 MHz. Both the transmitter and the receiver support 4 antennas. At the receiver, we design symbol timing detector, carrier frequency offset first acquisition and subsequent tracking mechanisms, channel estimation and MIMO detection. Simulation results show that the proposed symbol timing detection algorithm is more precise than the conventional algorithm. The CFO tracking mechanism also helps to improve the severe degradation in MIMO detection due to the residual synchronization error. In addition, by exploiting low-correlated spatial diversity, this system can combat highly frequency-selective fading channels for wide-band applications. We thus achieve satisfying system performance with 64-QAM constellation for 2.5-Gbps transmission rate.
