基于双正交小波信道估计改进的TR-UWB系统

A modified TR-UWB system based on biorthogonal wavelet channel estimation

针对超宽带(UWB)信号因脉冲持续时间短、时域分辨率高、在传播中出现密集多径现象的特点,利用小波函数和超宽带脉冲之间的相似特性,提出了一种基于双正交小波基的高效估计多径衰落幅度和时延等信道参数的信道估计算法,以便接收机能捕获足够的信号能量。通过滑动相关实现了同尺度上信号与小波的内积运算,避免了峰值搜索过程,简化了估计器的结构。同时,基于由信道冲激响应估计值合成的本地相关模板信号,提出了改进的发射-参考超宽带(TR-UWB)系统。Monte-Carlo 仿真结果表明,该算法的归一化均方误差较小,改进的 TR-UWB 系统能有效抑制参考符号中噪声的影响,系统性能优于传统 TR 接收机。

Considering the high time resolution of short ultra-wideband （UWB） signal and the large number of resolvable multipaths arriving at the receiver, a novel channel estimator was proposed for UWB systems to estimate the attenuations and delays of paths. It was based on biorthogonal wavelet bases and took advantage of the similarities between wavelets and UWB waveforms. The inner product between the received signal and wavelet at the same scale was implemented by a sliding correlator, which avoided the peak searching process and led to a simple channel estimator with considerable accuracy. A modified TR （transmitted-Reference）-UWB system was also presented. It was based on the reconstructed local template signal through estimated channel impulse response. The simulation results show that the channel estimation approach can reach a small mean square error, and the modified TR-UWB can effectively reduce the noise contained in reference signals. In addition, the proposed system performs better than conventional TR receivers