【作者】 张兰；

【导师】 李一兵；

【作者基本信息】 哈尔滨工程大学 ， 通信与信息系统， 2008， 硕士

【摘要】 近年来,超宽带通信技术以其良好的特性被业界认为是未来短距离高速无线通信的最佳解决方案。但是超宽带信号脉冲持续时间短,功率谱密度极低,并且超宽带信道具有密集多径的特性,因此接收端的信号捕获便成为一个十分关键的问题,本课题就跳时超宽带(TH-UWB)信号的同步问题进行了深入全面的研究。重点对两种同步算法进行了研究并给出了仿真结果及分析。基于最小二乘估计的同步算法通过合理建模把同步归结为估计接收信号和本地模板信号之间最小的欧几里得距离,该算法还可估计出信道冲激响应,用于相关接收机,给出了详细的推导过程。理论推导和仿真结果表明该算法具有算法简单明了,同步过程对于定时误差不敏感,而且只需较少比特数就能达到较好的捕获性能,是一种切实可行的同步算法。对现有基于带噪模板的同步算法(TDT-Timing with Dirty Template)进行了改进,先利用带噪接收信号的相邻两个码元长的互相关来实现帧同步,再利用本地无噪模板在两帧内利用滑动相关达到脉冲级同步,给出了改进前后的BER及归一化MSE值的比较。仿真结果表明与滑动相关相结合的TDT算法继承了TDT的只需积分清洗操作就可达到帧同步的优点,又将滑动相关限制在两帧内,大大减小了计算量,又改善了系统性能。并给出了与基于Hermite正交脉冲的TDT算法的捕获概率和MSE方面的比较。更多还原

【Abstract】 In recent years, UWB (Ultra-Wide Band) communication which has many advantages is believed to be the optimum solution for short distance and high speed communications in the future. However, because of the ultra short pulses and ultra-low power spectral density of UWB signals, the synchronization of the received signals is a critical problem to be solved. The paper has done some deep and full studies of acquisition and synchronization of TH-UWB signals.Two kinds of UWB synchronization algorithms are mainly studied and analyzed. The synchronization can be achieved by estimating the minimum Euclidean distance of the received signal and the local template signal in the least square estimation algorithm, channel estimation can also be achieved at the same time and can be used in the correlation receiver. Simulation results show that this algorithm has better acquisition performance and is feasible.This paper also gives an improved version of TDT (Timing with Dirty Template) algorithm. First, using the correlation of the adjacent bits of received dirty signals to realize frame synchronization, then sliding correlation in the adjacent two frames is done to realize chip synchronization. BER and MSE comparison before and after adding the sliding correlation are given. Simulation results show that TDT with sliding not only inherits the simpleness of the original TDT algorithm which only needs integration and clean calculation to achieve the frame synchronization, but also limits the sliding correlation in two frames, which greatly deduces the calculation amount, The improved TDT with sliding correlation and the TDT based on Hermite orthogonal are also compared from the view of acquisition probability and MSE.更多还原