一般來說，正交分頻多工系統常常藉由加入循環前綴碼來預防時變多重路徑通道間的訊號干擾。然而，循環前綴碼的出現會大大地降低有效的資料傳輸速率，因此，現在很多人開始研究不加循環前綴碼的正交分頻多工系統，而且延伸到不加入循環前綴碼的多輸入多輸出的正交分頻多工系統。但是一般這樣的系統會受到天線數量的限制，在這樣的系統下，接收天線的數量必須大於傳輸天線的數量才可以運作。因此，在這篇論文裡，我們一開始介紹加入空時區塊編碼的多輸入多輸出之正交分頻多工系統架構，而且緊接著，我們會證明在我們提出的架構下，接收天線數量是可以跟傳輸天線數量相等，只要接收天線大於一根就好，也就是多輸入多輸出系統的最基本要求。這樣的架構是有利於最近討論火熱的行動通訊規格3GPP LTE；他的規格就是要求多輸入多輸出的天線為2對2或者是4對4這樣的接收端與傳輸端的天線相等。這篇論文我們也在考慮了傳送端發射器功率下去降低峰均值功率比，在接收端的部份，我們又另外考慮IQ不平衡下對系統的影響，我們分別用了適應性Volterra預先失真的技術和加入了功率估測的盲閉式適應性補償器來解決上述的問題。在IQ不平衡補償器後面的等化器的部分，我們使用一個GSC架構的適應性濾波器來做干擾消除，而且我們也使用PA的架構來更進一步降低等化器的複雜度。如模擬結果所示，在加入了預失真器和IQ不平衡補償器之下，我們建議的無循環前綴碼的空時區塊編碼的多輸入多輸出正交分頻多工系統的效能和一般有加入循環前綴碼的效能是很接近的，這也表示說我們所提出的方法是可行的。

Orthogonal frequency division multiplexing (OFDM) systems with cyclic prefix (CP) can be used to protect signal from the time-variant multipath channel induced distortions. However, the presence of CP could greatly decrease the effective data rate, thus many recent research works have been focused on the multiple-input multiple-output (MIMO) OFDM systems without CP (CP-free), equipped with the space-time block codes (ST-BC). The constraint of the conventional MIMO-OFDM (without using the ST-BC) system is that the number of receive-antenna has to be greater than the transmit-antenna. In this thesis, we first consider the ST-BC MIMO-OFDM system and show that the above-mentioned constraint can be removed, such that the condition become that the receive antenna should be greater than one, that is the basic requirement for MIMO system. It is particular useful and confirm to the recently specification, e.g., 3GPP LTE (Long Term Evolution) where the system deploy the 2×2 or 4×4 antennas systems. This thesis also considers the effects of peak-to-average power ratio (PAPR) in the transmitter and In-phase/ Quadrature-phase (IQ) imbalance in the receiver, and solves them by using the adaptive Volterra predistorter and blind adaptive filtering approach of the nonlinear parameters estimation and compensation, along with the power measurement, respectively. After the compensator of IQ imbalance in the receiver, an equalizer under the framework of generalized sidelobe canceller (GSC) is derived for interference suppression. To further reduce the complexity of receiver implementation, the partially adaptive (PA) scheme is applied by exploiting the structural information of the signal and interference signature matrices. As demonstrated from computer simulation results, the performance of the proposed CP-free ST-BC MIMO-OFDM receiver is very similar to that obtained by the conventional CP-based ST-BC MIMO-OFDM system under either the predistortion or compensation scenario.

致謝 i
中文摘要 ii
Abstract iii
Contents iv
List of Figures vi
1 Introduction…………...................................................1
2 Model Description of the ST-BC MIMO-OFDM Systems and IQ Imbalance…………………………..5
2.1 Introduction…………………………………………5
2.2 CP-based ST-BC MIMO OFDM Systems……….7
2.3 IQ Imbalance……………………………………...12
2.4 Direct-Conversion (Zero-IF) Receiver………….15
3 Transceiver Design of CP-Free ST-BC MIMO-OFDM Systems under IQ-Imbalance……………………….17
3.1 Introduction………………………………………..17
3.2 Transmitter of ST-BC MIMO-OFDM Systems….20
3.2.1 CP-free ST-BC MIMO OFDM System…………20
3.2.2 Transmitter of ST-BC MIMO-OFDM Systems with Volterra-based Predistorter…………………………..23
3.3 Receiver Design for the ST-BC MIMO-OFDM Systems………………...................................................26
3.3.1 IQ Blind Adaptive Compensation with Power Measurement….............................................................26
3.3.2 Equalization with PA-GSC Configuration………………….....................................31
4 Computer Simulations………………….................37
5 Conclusions…………………………………...........43
Appendix A Derivation of PA-GSC…………….........45
References……………………………………….........48

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