合作式多輸入多輸出(MIMO, multiple-input multiple-output)技術因可有效提升系統效能與增加傳輸速率，近年來已受到相當大的關注。同時，將正交分頻多工(OFDM, orthogonal frequency-division multiplexing)和MIMO傳輸技術相互結合產生的MIMO-OFDM技術也已成為下一代無線傳輸系統的主要技術。而合作式多輸入多輸出(cooperative MIMO)技術將散佈於空間中的數個單天線裝置加以聯合創造出虛擬陣列天線，也受到相當大的關注。但在合作式多輸入多輸出系統中，由於各個節點傳送的信號到達接收端時間並不一致，且會受到不同的頻率偏移(CFO, carrier frequency offset)影響，其同步技術則更具挑戰性。
在此論文中，我們針對cooperative MIMO系統提出基於部分扎德奧夫-朱序列(partial Zadoff-Chu sequence)的訓練序列與同步技術。在我們所提出的訓練序列設計中，我們以交錯方式將部分Zadoff-Chu序列擺放在互斥集合所包含的子載波上。此擺放方式不僅保證訓練序列在頻域之分離性，亦導致其時域訊號之可區隔特性；此特性除可同時降低訓練序列間之相互干擾，亦可在時域完成多載波頻率偏移之估測。相較於現今同步技術，我們所提出的方法可在時域完
成所有時間與頻率同步動作。除此之外，我們所提的訓練序列有良好的自相關和互相關特性，因此在同步的效能上有卓越的表現。

Recently, cooperative multiple-input multiple-output (MIMO) systems have attracted increasing attention for their feasibility and flexibility over MIMO systems. Meanwhile, combining cooperative MIMO systems with orthogonal frequency division multiplexing (OFDM) has been recognized as a promising technology to support next-generation wireless communication systems. In cooperative MIMO systems, however, the signals transmitted by cooperating nodes may arrive at the receiver on distinct timing and be affected by multiple carrier frequency offsets (CFOs). As a result, synchronization is a challenging and important task in cooperative MIMO systems.
In this thesis, we propose a synchronization scheme based on partial Zadoff-Chu sequences for cooperative MIMO systems. In the proposed preamble design, partial Zadoff-Chu sequences are placed on disjoint sets of subcarriers in an interleaved manner. Such an arrangement not only guarantees frequency-domain training signal separation, but also produces separable time-domain training signals to cope with the multiple CFOs. Accordingly, both time and frequency synchronization can be done in the time domain, while they are achieved in the time and frequency domains, respectively, in most existing synchronization schemes for cooperative MIMO systems. Furthermore, the proposed training sequences enjoy good auto-correlation and cross-correlation properties, which leads to superior synchronization performance as compared with existing synchronization schemes.

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