基于稀疏小波变换的超宽带低信噪比信号检测算法.pdfVIP

学兔兔 第34卷 第4期 仪 器 仪 表 学 报 Vo1．34 No．4 2013年4月 Chinese Journal of Scientific Instrument Apr．2013 基于稀疏小波变换的超宽带低信噪比 信号检测算法米 徐 湛 (北京信息科技大学信息与通信工程学院 北京 100085) 摘 要：脉冲超宽带信号是时域瞬态脉冲，功率谱密度极低，在远距离通信时，信号淹没在噪声中较难检测，对前端采样率要求 较高。针对脉冲超宽带低信噪比检测问题，提出了一种在脉冲波形先验信息已知条件下，基于稀疏小波变换的低信噪比检测方 法。针对超宽带信号在小波域具有稀疏分布这一特征，依据压缩传感理论，分析并仿真了稀疏基矩阵选择时域采样矩阵和小波 矩阵时，信噪比对于性能的影响，提供了重构算法中迭代终止门限的选择方法。仿真实验表明，相对于稀疏基矩阵为时域采样 矩阵，采用小波变换矩阵可以在较低信噪比条件下实现超宽带信号的降噪重构。 关键词：超宽带脉冲；压缩传感；稀疏小波变换；正交匹配追踪；信噪比 中图分类号：TN914 文献标识码：A 国家标准学科分类代码：510．40 Detection algorithm for low SNR signal in UWB systembased on sparse wavelet transform XU Zhan (School of Information and Communication Engineenng，Beijing Information Science and Technology University，Beifing 100085，China) Abstract：The ultra wideband impulse radio(IR—UWB)signal is time domain transient pulse with low power spectral density．In long—distance communication，the signal is submerged in noise and is difficult to be detected；therefore high front end sampling rate is required，which is a formidable challenge．Aiming at the problem of IR—UWB signal detection in low SNR，in case that the waveform of the UWB pulse signal is known，a sparse wavelet transform based detection method is proposed in low SNR condition．According to the characteristic that UWB signal has sparse distil— bution in wavelet domain and based Oll compressed sensing theory，time domain sampling matrix and wavelet matrix are selected as the sparse basis matrix，the influence of SNR on BER is analyzed and simulated，and the selection method for iteration stopping threshold in the