Research Of Synchronization Techniques In Ultra-Wideband Wireless Communication System

UWB technology has become an interest research area in wireless communication, and it is considered as one of the key technologies for the next generation wireless communication. Presently, UWB wireless communication systems are classified into two main forms: non-carrier UWB system and carrier modulated UWB system. Meanwhile, carrier modulated UWB system can be implemented using many schemes, in which DS-CDMA UWB and MB-OFDM UWB are the two main ones.OFDM technology, with the merits of high bandwidth efficiency, robustness to multi-path and simplicity of equalization, is especially suitable for wideband wireless communication. In this thesis, an OFDM based UWB system is studied, emphasizing particularly on the synchronization technologies.Following the introduction of the background knowledge of UWB and the basic principle of OFDM, synchronization technologies are analyzed in more detail. Some non-ideal effects on the performance of OFDM systems are discussed. And some typical OFDM synchronization schemes are presented. After investigating some existing synchronization schemes, one symbol timing scheme based on special training sequences and one frequency synchronization scheme based on pilot symbols are put forward. By using FZC sequence or FH sequence, the symbol timing scheme is independent of frequency offset and can achieve timing in one step. A frequency synchronization algorithm is provided, and then one estimation scheme is designed, which guarantees both estimation range and estimation precision.Besides, the whole synchronization schemes for the OFDM based UWB system are designed. First, the basic structure and the channel model of the UWB emulation system are introduced. Then, appropriate synchronization schemes for frame detection, symbol timing, frequency offset estimation and phase tracking are discussed separately. Finally, in order to evaluate the performance of the whole synchronization schemes, the system performances with ideal and non-ideal synchronization are compared.