共查询到19条相似文献,搜索用时 140 毫秒
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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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一种基于门限判决的窄带干扰抑制频域自适应算法 总被引:1,自引:0,他引:1
为了解决直接序列扩频系统中强窄带干扰的抑制问题,提出一种基于门限判决的频域自适应算法。该算法利用干扰门限值估计和优化自适应滤波器参数,不但大大加快了收敛速度还提高了跟踪能力,而且保证了较小的稳态误差。理论分析和仿真结果表明:该算法可以有效抑制直扩系统中时变窄带干扰。 相似文献
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介绍了一种频域自适应窄带干扰抑制的方法,该方法基于离散DFF(傅里叶变换)技术,在频域采用N-∑算法自适应确定干扰抑制门限,可以有效地去除窄带干扰对宽带通信系统解调性能的影响,适用于DSSS(直接系列扩频)信号中去除强窄带干扰信号的影响。该算法简单高效,非常适合于数字硬件实现,实验和实测结果表明了该算法的有效性。 相似文献
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低信噪比下基于自适应门限的窄带干扰抑制研究 总被引:3,自引:0,他引:3
对一种基于自适应门限的变换域窄带干扰抑制技术进行了研究。该技术根据在低信噪比下接收信号经过快速傅立叶变换后数据的统计特性,估计出高斯白噪声和干扰之间的门限值,然后将高于门限的干扰谱线幅度值抑制到与噪声相近的程度,大大减少了干扰信号的功率,从而提高信噪比。理论分析和仿真结果表明,该技术改善了系统性能且便于硬件实现。 相似文献
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We compare single user digital multi-carrier spread spectrum (MC-SS) modulation with direct sequence (DS) SS (with a modified implementation) in the presence of narrowband interference (NBI) and multipath fading. We derive closed-form expressions for the symbol error probability for both the linear MMSE receiver as well as the conventional matched-filter receiver under different scenarios: additive white Gaussian noise (AWGN) channel with NBI, multipath channel with or without NBI. We show that DS-SS can achieve the same performance as MC-SS if the spreading code is carefully designed to have perfect periodic autocorrelation function (PACF). On the other hand, MC-SS is more robust to narrowband interference and multipath fading than is DS-SS with the widely used spreading codes that do not possess perfect PACE. Our analysis reveals that the performance improvement of MC-SS is precisely due to the implicit construction of an equivalent spreading code having nonconstant amplitude but possessing perfect periodic autocorrelation 相似文献
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We analyze the performance of ultra-wideband (UWB) communications in the presence of interference. Closed-form expressions are provided for the jam resistance of UWB with binary pulse position modulation utilizing rectangular pulses. A simple approximation is obtained for the special case of tone interference. The jam resistance analysis is extended to more practical UWB waveforms such as Gaussian and Rayleigh monocycles. A comparison between the interference suppression capabilities of UWB and direct-sequence spread-spectrum (DS-SS) is carried out under conditions similar to both systems. It is shown that in most cases, the jam suppression of UWB is superior to that of DS-SS. 相似文献
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Ultra-wideband (UWB) technology has been considered to offer an innovative solution for future short-range high-speed wireless
communications. These systems use very low transmission power, spread over a bandwidth of several gigahertz. The very low
transmission power and the large bandwidth used, enable UWB radio systems to co-exist with other narrowband systems over the
same frequency band without interfering the narrowband systems. Nevertheless, these narrowband systems may cause interference
which may jam the UWB receiver completely. Since standard narrowband interference suppression techniques are not applicable,
techniques for interference suppression have to be developed. In this paper, the method of the local polynomial estimator
in time-hopping impulse radio (TH-IR) for UWB communication is considered, which should not estimate any parameter of channel.
And the narrowband interference (NBI) is modeled as a stationary process. Theoretical analysis of this algorithm reveals that
it can eliminate the narrowband interference almost completely and can be computed by simple expression. Moreover, the sampling
rate is very low. 相似文献