Research On Synchronization Technology For UWB Wireless Communication System

Compared with narrowband communication, the Ultra-wideband (UWB) wireless communication has many advantages, such as low cost, low power consumption, high transmission rate, good multipath resolution capability, so it has fine prospect in commercial, household and personal multimedia networks, which attracts extensive attentions at home and abroad. Ultra-wideband has been proposed as the realizing scheme of physical layer in the high data-rate wireless personal area network (WPAN) by IEEE standardization working group.The UWB wireless communication system has advantages over the tradition communications system, but we have to solve many key technologies before realizing it. As in other communication systems, synchronization plays a crucial role in UWB communication systems. The receiver in UWB communication system only knows the propagation delay of the received signal precisely and synchronizes with the local "template", then it can despread and demodulates the received signal. Due to the ultra short duration of UWB pulses, the phase offset of pseudo-random code and the severe frequency selectivity of UWB channels, synchronization becomes a challenging task for UWB system design.In this paper, it is focused on the research of synchronization technology of the high speed DS-UWB communications system. In the first three chapters of paper, it simply introduce the ultra-wide band technical historical development, definition, characteristics, key technologies and challenges, as well as the channel model and the system model of ultra-wide band. In the fouth chapter, we mainly introduce synchronization technology, and then introduce and conclude the traditional and existing synchronization methods.The synchronization technology of the high-speed DS-UWB system is analysised and researched in the fivth chapter of paper. We proposed two acquisition methods. Firstly, for rapid and reliable UWB signal acquisition, we propose an improved two-stage search scheme, in which the two different steplengths and two thresholds are employed for each stage in the proposed search scheme. Secondly, we propose an improved signaling format in which the final long spreading sequence used is derived from the combination of two short sequences. According to the feature of the proposed signaling format, a two-stage acquisition scheme is proposed and studied in detail. Analytical and numerical results show that the acquisition time can be reduced greatly with the proposed scheme. In order to evaluate the acquisition performance of proposed algorithms in realistic channels, the channel model CM1 and CM3 which is the 802.15.3a work team suggested is employed in the simulations. The analysis and numerical results suggest that, compared with the traditional acquisiton algorithm, the performance of the mean detection time and mean miss probability is greatly improved for Two-Stage acquisition method. The Joint Sequence Spread Spectrum algorithm, under the situation of no loss of mean miss times, can significantly reduce the average detection time.