基于能量检测和NBI消除的UWB接收机信号检测  

Signal detection for energy detection and NBI mitigation based UWB receiver

作　　者：余沺沺 金彦亮[1] 

机构地区：[1]上海大学特种光纤与光接入重点实验室,上海200072

出　　处：《电子测量技术》2016年第8期144-149,共6页Electronic Measurement Technology

摘　　要：针对基于能量检测的超宽带（UWB）接收机提出了信号检测算法,此系统使用了平方率（SL）窄带干扰（NBI）消除技术来去除窄带干扰。由于使用能量检测方案,因此在高斯白噪声的情况下,统计检测量可以表示为统计独立的高斯随机变量的平方和。当有用信号不存在时,统计检测量服从中心χ^2分布,其自由度为积分器输入信号的二倍时间—带宽积。当有用信号存在时,统计检测量服从自由度相同的非中心χ^2分布,且依赖于因子λ。λ和系统参数有关,这些参数包括有用信号的能量和带宽,干扰信号的功率谱密度和带宽,以及噪声的功率谱密度。非中心的χ^2分布通过检测门限和自由度的转化可以化为中心χ^2分布。MATLAB数值计算显示了接收机工作特性（ROC）曲线,即检测概率Qd和虚警概率Q0的关系。从图中曲线可以看出,系统的参数和检测性能密切相关,比如当系统带宽变动时,虚警概率可以保持不变,而检测概率可能变为原来的2倍。结果表明,可以通过改变系统参数得到期望的检测性能。The signal detection algorithm is proposed for the energy detection based ultra wideband（UWB）receiver which utilizes the square law（SL）narrowband interference（NBI）mitigation technology to mitigate the narrowband interference.Because of the energy detection scheme,the decision statistic can be expressed as the sum of the squares of statistically independent Gauss variates in white Gaussian noise.When the signal is absent,the decision statistic obeys the central chi-square（χ^2）distribution with the number of degrees of freedom equal to the twice of the timebandwidth product of the input before the integrator.When the useful signal exists,the decision statistic obeys the noncentralχ^2 distribution with the same number of degrees of freedom and depends on the factorλ.λis associated with system parameters,including the energy and bandwidth of the useful signal,the power spectral density and bandwith of the interference,and the power spectral density of the noise.The noncentralχ^2 distribution can be converted to the centralχ^2 distribution by changing the threshold and the number of degrees of freedom.Numerical computations by MATLAB demonstrate the receiver operating characteristic（ROC）curves which represent the relationship between the probability of detection Qdand the probability of false alarmQ0.From the curves in the figures,we can see that the system parameters have close relationships with the detection performance,for example,when the bandwith of the system is changed,the probability of false alarm can remain unchanged,while the probability of detection can be changed to two times than the origal one.The results show that the desired detection performance can be achieved by changing system parameters.

关 键 词：超宽带 窄带干扰消除 信号检测 接收机工作特性 

分 类 号：TN92[电子电信—通信与信息系统]