本論文於時變多路徑通道的假設下，提出可應用於無循環前置碼及具空-時區塊編碼之多輸入多輸出正交分頻多工系統上傳端的新式接收器架構。 一個不運用多餘冗員來移除符間干擾之系統的效能，可藉由此接收器來進一步改善，同時，能有效的提升頻譜效率。 一般來說，無循環前置碼的正交分頻多工接收器不能以簡單而有效的方式來一併處理載波干擾以及符間干擾 (區塊干擾)等問題。
本篇論文利用空間和頻率的資源，提出結合斜面投影器之新式頻域決定迴授等化器, 用以消除接收端的符間干擾和載波干擾。 斜面投影基本上為一非正交投影技術，此方法可以用來有效處理結構雜訊的問題( 例如:符間干擾項)。透過電腦模擬分析,我們將論證所提出之架構在效能上，非常接近傳統有循環前置碼及具空-時區塊編碼之多輸入多輸出正交分頻多工系統。

This thesis present a new receiver framework for the cyclic-prefix free (CP-free) MIMO-OFDM system, equipped with the space-time block coded (ST-BC) uplink transmission over (slowly) time varying multipath channels. Usually, without CP in the OFDM system the inter-carrier interference (ICI) could not be removed, effectively, at the receiver, when the inter-symbol-interference (ISI) has to be taken into account.
In this thesis, by exploiting the spatial and frequency resources, we propose a novel frequency-domain decision-feedback equalizer, associated with the oblique projection (OB), to combat the effects of ISI and ICI, simultaneously. The OB is a non-orthogonal projection and is very useful to deal with the structure noise (e.g., the ISI term). From computer simulations, we observe that the performance of propose scheme can perform very close to the conventional CP-based MMO-OFDM with the ST-BC.

Acknowledgments i
Abstract ii
Contents iii
List of Figures v
Chapter 1 1
Introduction 1
1.1 Motivation and Background 1
1.2 Content and Contribution of Thesis 3
Chapter 2 5
General Model Description for ST-BC MIMO-OFDM System 5
2.1 Introduction 5
2.2 Fundamental Concepts of Space-Time Block Code 6
2.3 Fundamental Concepts of OFDM 9
2.4 CP-based ST-BC MIMO OFDM System 11
2.5 CP-free ST-BC MIMO OFDM System 16
2.5.1 Equalization Based on ISI/ICI Suppression Scheme 21
Chapter 3 25
Frequency Domain Equalizer Design with Oblique Projection 25
3.1 Introduction 25
3.2 The Concepts of Projection Operator 26
3.3 Frequency Domain Decision Feedback Equalizer Associated With Oblique Projection 31
Chapter 4 40
Computer Simulations 40
4.1 Preliminaries 40
4.2 System BER Performance 41
4.3 Resistance to Channel Delay Spread 44
Chapter 5 47
Conclusions 47
Appendix A 48
Derivation of QR-Based Oblique Projector 48
Appendix B 52
Linear ZF Equalizer 52
Appendix C 53
Linear MMSE Equalizer 53
References 55

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