結合空頻區塊碼(SFBC)與正交分頻多工(OFDM)的系統因為可達到空間和頻率分集增益，近年來已被廣泛採用，但正交分頻多工技術對載波頻率偏移(CFO)非常敏感，會造成嚴重的載波間干擾(ICI)，進而影響系統的效能。在本篇論文中，我們針對採用Alamouti編碼的SFBC-OFDM合作式中繼系統提出可以達到干擾自消除(ICI self-cancellation)的新型傳收機設計，包含兩個中繼器系統與四個中繼器系統的情況；每一設計之傳送端使用適當的Alamouti SFBC編碼器，而在接收端則包含共同CFO補償方法、對應的SFBC解碼器及partial PIC模組以達到干擾自消除之目的。電腦模擬結果顯示，我們所提出之兩個中繼器系統的新型傳收機設計比現有相關方法具有較佳的錯誤率效能，但卻沒有明顯增加複雜度，而所提出之四個中繼器系統的新型傳收機設計亦具有良好的錯誤率效能。

Cooperative relay systems have drawn attentions in recent years because they can use an appropriate number of relays to form a virtual multiple-input multiple-output (MIMO) scenario to improve communication links. Space frequency block coding (SFBC) is a prominent spatial diversity strategy for MIMO systems, and it has been widely adopted with orthogonal frequency division multiplexing (OFDM) to achieve both spatial and frequency diversity. One major problem associated with an SFBC-OFDM cooperative relay system is the existence of multiple carrier frequency offsets (CFOs), and this would cause serious intercarrier interference (ICI) and degrade the system performance greatly. In this thesis, new transceiver designs are proposed for SFBC-OFDM cooperative relay systems, where an appropriate SFBC Alamouti encoder is adopted at the transmitter and a common CFO compensation unit, a modified SFBC decoder, and an iterative partial parallel interference cancellation (PIC) module are used at the receiver. Both of the two-relay and four-relay cases are investigated. Simulation results demonstrate that the proposed transceiver design for the two-relay case outperforms previous related works, while the one for the four-relay case also achieves pretty good performance.

ABSTRACT i
CONTENTS ii
LIST OF FIGURES iv
LIST OF TABLES vi
I. INTRODUCTION 1
II. BACKGROUND 4
III. A NEW TRANSCEIVER DESIGN FOR THE TWO-RELAY CASE 10
IV. A NEW TRANSCEIVER DESIGN FOR THE FOUR-RELAY CASE
V. SIMULATION RESULTS 22
A. Performance of the Proposed Two-Relay Scheme 22
B. Performance of the Proposed Four-Relay Scheme 27
VI. CONCLUSION 30
APPENDIX DERIVATIONS OF THE OPTIMAL P(2) FOR THE FOUR-RELAY SCHEME 31
REFFERENCES 36

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