在這篇論文，我們主要研究基於空時區塊編碼的多輸入多輸出正交分頻多工系統在循環前置碼不足的情況下，使用結合斜面投影器及頻域決策回授等化器的系統效能，這個系統架構最早由 Chern與Wu所提出，在假設接收端已知通道情況下，此系統可以達到非常接近具備循環前置碼系統的系統效能．在這篇論文我們將要提出一個使用最佳導航訊號安排的柵狀通道估測器來搭配結合斜面投影器的頻域決策回授等化器，同時我們也將改變系統的參數來驗證此系統架構在具備通道估測誤差下的系統效能

Two of the key factors playing a role in the globalization of wireless technologies are international standardization and global availability of spectrum. The pre-coding scheme with the cyclic-prefix (CP) is one of the most popular schemes used the orthogonal frequency division multiplexing (OFDM) to prevent the inter-block interference (IBI). In the CP-OFDM system the length of CP is normally one fourth or one eighth of the transmitting data block. In practical applications, the pilot-assisted sequence is adopted for channel estimation. However, to achieve spectrum efficiency it is of interest to reduce or completely remove the CP (or named as the CP-insufficient). In thesis, we will consider the problem of transceiver design for CP-insufficient ST-BC MIMO-OFDM system that is based on the Oblique-based decision feedback equalizer, and was first proposed by Chern and Wu. It could perform successfully and achieve excellent performance that is closed to the ideal CP-based systems assumed that perfect channel information known at the receiver. In this thesis, we will extend their proposed by Chern and Wu by considering that the information of channel is not available at receiver. For estimating the channel state information, we adopt the block-type LS channel estimator with optimal pilot arrangement. Finally, we apply the results with the optimal channel estimator to the OB-based DFE equalizer to investigate the system performance under different system parameters to verify the superior of the proposed scheme.

Content
Abstract i
Contents iii
List of Figures iv
1. Introduction 1
2. The Space-time Block-coded MIMO-OFDM Systems
2.1 Introduction 6
2.2 Basic Concepts of OFDM Systems 7
2.3 Basic Concepts of Space-Time Block Code 9
2.4 CP-based ST-BC MIMO OFDM System 12
3 Design of ST-BC MIMO-OFDM Receiver with Optimal Channel Estimator
3.1 Introduction 19
3.2 Receiver Design for ST-BC MIMO OFDM Systems 20
3.2.1 Oblique Projection Operator Design in Time Domain 20
3.2.2 Decision Feedback Equalizer Design in Frequency Domain 26
3.3 Channel Estimation with optimal pilots 34
4. Computer Simulations
4.1 Introduction 39
4.2 System BER Performance 40
5. Conclusions 52
Appendix Two-stage receiver for CP-free ST-BC MIMO OFDM System 53
References 61

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