共查询到20条相似文献,搜索用时 93 毫秒
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基于门限估计的直扩通信系统窄带干扰变换域抑制方法 总被引:14,自引:1,他引:13
该文提出一种基于门限估计的直接序列扩频(DS-SS)通信系统窄带干扰变换域抑制方法。该方法对直扩通信系统接收信号变换域数据的分布特点进行了分析,并采用高斯分布对其作了近似.由于高斯分布的方差即为直扩信号和高斯白噪声方差之和,因此估计出变换域数据的方差,将为频域抑制滤波器的门限设置提供参考。该文采用最大似然比(ML)准则对方差进行了估计,从而实现了频域抑制滤波器的自动门限设制。理论分析和计算机仿真结果均表明,该方法能够有效地抑制直扩通信系统中的窄带干扰。 相似文献
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为解决宽带OFDM系统易受传统窄带信号干扰的问题,采用基于变换域通信(TDC)的OFDM系统,通过在变换域中的电磁环境采样结果,对OFDM信号进行设计,避免使用受干扰频谱传送信息。该方法在强窄带干扰得到抑制的同时,信噪比也不容易受到变换域滤波的影响。在加性高斯白噪声信道中的仿真结果表明,基于TDC的干扰抑制方法能够有效地抑制宽带OFDM系统的窄带干扰。 相似文献
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为进一步改进门限估计的直扩通信系统(DSSS)窄带干扰频域抑制性能,在对基于门限估计的直扩通信系统窄带干扰频域抑制方法性能做定性分析的基础上,采用估计门限和已知的粗门限相结合的思路,提出一种改进型门限估计的直扩通信系统(DSSS)窄带干扰频域抑制方法.该方法先通过最大似然估计估计出N(FFF长度)个频域数据的方差,再将高于粗门限的方差滤除,最后取滤波后各个方差的均值作为频域陷波器的参考门限.仿真结果表明该方法能够有效的抑制直扩通信系统中的窄带干扰. 相似文献
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为进一步改进门限估计的直扩通信系统(DSSS)窄带干扰频域抑制性能,在对基于门限估计的直扩通信系统窄带干扰频域抑制方法性能做定性分析的基础上,采用估计门限和已知的粗门限相结合的思路,提出一种改进型门限估计的直扩通信系统(DSSS)窄带干扰频域抑制方法.该方法先通过最大似然估计估计出N(FFF长度)个频域数据的方差,再将高于粗门限的方差滤除,最后取滤波后各个方差的均值作为频域陷波器的参考门限.仿真结果表明:该方法能够有效的抑制直扩通信系统中的窄带干扰. 相似文献
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直扩系统中抗窄带干扰技术 总被引:4,自引:0,他引:4
直扩序列扩频通信具有隐藏性,抗干扰能力强的特点,但对各种人为的大功率窄带干扰却无能为力,采用窄带干扰抑制技术,是抗各种人为干扰的一种有效手段,本文介绍各种干扰的抑制技术。 相似文献
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超宽带通信系统窄带干扰变换域抑制方法 总被引:1,自引:0,他引:1
结合UWB系统的工作特点,对信道中信号的频谱特性进行分析,在变换域(频域,或时间-尺度域)中设计出最佳脉冲波形,使其与周围电磁环境中含有干扰的变换域相互正交,从而有效地避开干扰.通过对环境的周期性重复采样,可使得UwB成为一个自适应抑制干扰的通信系统.仿真结果表明,设计的自适应抑制干扰脉冲比通常使用的Scholtz脉冲的性能更优,抗干扰能力更强.且此方法不需要在整个频段内降低UWB脉冲的功率谱密度,为提高UWB脉冲发射功率,增大UWB系统的通信距离,提供了一种灵活易行的参考型方案. 相似文献
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OFDM系统由于具有子载波的正交性从而可以充分利用频谱资源,鉴于当OFDM受到窄带干扰而影响较多的子载波时,会出现系统误码率性能严重恶化的现状。文中提出了一种OFDM系统窄带干扰消除技术,该技术在接收端检测出受干扰子载波,利用反馈信道告知发送端,并在发送端将受干扰的子载波不加调制的信息发送到信道中,而在信道中该部分子载波只受干扰信号的影响,接收端将干扰信息重构并储存,从而完成干扰消除确保正常通信。仿真和分析结果表明,该方法在不浪费频谱资源的情况下,能有效抑制OFDM系统的窄带干扰。 相似文献
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Performance Analysis of Narrowband Interference Suppression in Orthogonal Code ModulationSpread Spectrum System 总被引:1,自引:0,他引:1
1IntroductionInaspreadspectrumsystem,theuser'ssignalisspreadtoawidebandsignalfortransmission,thenthereceivedsignalswillbedecorrelatedbacktotheoriginalone.Theprocessinggainresultedfromthisprocessprovidestheadvantagesofperformanceimprovementtocombatint... 相似文献
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The requirement to suppress narrowband interferences in CDMA communications stems from the overlay concept, i.e., coexistence of different types of signals in the same frequency band. The conventional approach to rejecting the narrowband interferences has been to whiten the received signal containing the interference, prior to spread spectrum demodulation. In this paper, it is proposed to achieve the interference rejection through spatial processing. The main benefit of this approach is its robustness with respect to the interference bandwidth. Stepping up from single domain spatial processing to space-time processing provides degrees of freedom for both overlay interference cancellation and diversity combining. Two space-time architectures, cascade and joint-domain, are studied and compared to a Rake receiver preceded by a whitening filter. Main contributions of the paper are the development of analytical expressions of (1) the efficiency of each method, (2) the p.d.f.'s of the output SNR in a Rayleigh fading environment, and (3) the error probability associated with each method. The analysis therein demonstrates that the joint-domain architecture outperforms the cascade configuration, which in turn is superior to the whitening filter-Rake combination. 相似文献
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空时Rake MMSE合并结构的窄带干扰抑制性能分析 总被引:1,自引:0,他引:1
对多径衰落信道条件下空时rakeMMSE合并结构的窄带干扰抑制性能进行了分析,结果表明相比其它空时rake合并结构,MMSE合并结构具有最优的抑制窄带干扰和对抗信道多径衰落的性能,它受干扰功率的影响较小,而且该种合并结构仅需较少的接收天线即能获得较好的性能。 相似文献
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Multiuser interference suppression in coded direct sequence code division multiple access (DS-CDMA) uplink channels is significantly impacted by the application of the turbo processing concept. This paradigm essentially involves the iterative exchange of soft information between a multiuser demodulator and a bank of single-user decoders, to their mutual benefit. The present work proposes a joint iterative minimum mean square error (MMSE) multiuser and narrowband interference suppressor for coded asynchronous DS-CDMA channels. Since the parameters of the narrowband interference are unknown a priori, the first iteration in this scheme is effectively just MMSE multiuser interference suppression. The outputs of all users' soft decoders (available at the end of each iteration) are fed back to subtract their (estimated) cumulative contribution from the received signal vector. The residue comprises the narrowband interference embedded in wideband noise, so that the former can be piecewise interpolated over chip intervals of appropriate duration, and then subtracted from the received signal, to provide a narrowband-interference-free input signal for the next iteration. The soft-decoded feedback estimates of the interferers' signals are used in each iteration also to perform soft MMSE multiuser interference suppression, in conjunction with subtractive interference cancellation. This scheme performs well at both low and high received signal powers, and displays the successive cancellation property across iterations, exhibiting good near-far resistance. Introducing multisensor arrays at the receiver relaxes the limitations imposed by the inherent suboptimality of MMSE multiuser demodulation, insofar as it enhances interuser separation, now in the spatial sense. Simulations indicate that the performance of the proposed technique surpasses that of all existing suboptimal algorithms in this context. 相似文献
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