复杂环境下的UWB脉冲成形算法

针对超宽带定位系统在多用户和弱信号环境下接收端易出现码间串扰(inter symbol interference, ISI)和多用户干扰(multiuser interference, MUI)等问题,提出一种基于修正最小均方误差估计(minimum mean square error estimation, MMSE)的自适应迭代算法进行超宽带(ultra wideband,UWB)脉冲设计。该算法选取修正Hermite多项式(modefied Hermite polynomial, MHP)作为脉冲设计基函数。通过分析MHP的时频特性对最小均方误差估计准则下组合脉冲的各阶MHP系数进行修正,在此基础上根据组合脉冲功率谱密度与美国联邦通讯委员会(federal communications commission, FCC)辐射掩蔽之间的拟合程度设计自适应算法,对组合脉冲进行自适应调整实现脉冲设计。仿真结果表明该方案获得的脉冲有较高功率利用率,同时在多用户接入和弱信号检测方面也具备很强的适用性。

UWB pulse shaping algorithm in complex environment

In order to reduce the inter symbol interference (ISI) and multiuser interference (MUI) which exist in the ultra wideband positioning system under the multiuser and weak signal environment, an adaptive iterative algorithm based on minimum mean square error estimation (MMSE) for ultra wideband (UWB) pulse design is proposed. Modified Hermite polynomial (MHP) is selected as the basis function of the designed pulse. By analyzing the time frequency characteristics of MHP, coefficients of combined pulse are modified by the MMSE criterion. According to the fitting degree of power spectrum density between combined pulse and Federal communications commission (FCC) radiation masking, an adaptive algorithm is designed to realize pulse design. Simulation results show that the proposed scheme can obtain higher power utilization, and also obtain strong applicability in multiuser access and weak signal detection.