低峰均功率比時空頻三維碼之研究

Abstract

隨著個人化通訊需求的迅速發展及多媒體訊息交流的急遽增加，強化無線接取技術以因應高速、多元及高品質傳輸要求，已成為發展新一代無線通訊系統時所須考量的重要課題。為符合這樣的要求，目前都是以多重輸入多重輸出（Multiple-Input Multiple-Output, MIMO）和正交分頻多工（Orthogonal Frequency Division Multiplexing, OFDM）兩技術結合之系統來達成，因此本論文會先針對MIMO和OFDM兩系統分別做介紹，並接著在多重輸入輸出-正交分頻多工（MIMO-OFDM）系統架構下去設計可從空間、時域、頻域抵抗通道錯誤之新式三維碼，但由於系統架構應用OFDM技術，所以會承襲OFDM技術先天高峰均功率比（Peak-to-Average Power Ratio, PAPR）之缺點，因此我們也針對此一缺點，設計出具低峰均功率比特性之新式三維碼，所得新式三維碼不僅可在空間、時域、頻域獲得最佳分集增益以提升系統傳輸品質，同時亦能大幅降低正交分頻多工系統之峰均功率比以簡化收發機之硬體需求。

With the fast development of personal communications and the increasing need of multi-media messaging, the major topic for future wireless communications will be to effectively enhance the capability of radio access to provide excellent spectral efficiency and system capacity. Recently, MIMO-OFDM systems are mostly used to provide high data rate transmission and multi-media services. Thus, the goal of the thesis is to combine the STF coding for MIMO-OFDM systems and establish the related theoretical fundamentals. Moreover, we also consider the PAPR problem in OFDM systems. The proposed STF codes not only can achieve the maximum diversity gain to optimize the transmission quality but also can mitigate the high PAPR of OFDM signals to avoid the high cost amplifiers in the transmitter and receiver.