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针对直接序列扩频系统,理论推导出单音干扰和窄带干扰下系统处理增益的精确计算公式,并对所得公式进行了数值仿真。数值仿真结果表明,单音干扰对直接序列扩频系统的干扰能力与其相对于扩频系统的载波位置密切相关;窄带干扰对直接序列扩频系统的干扰能力与其相对于扩频系统的载波位置和干扰带宽密切相关。研究结果可为直接序列扩频系统的设计提供参考。 相似文献
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一种基于RS码序列的软扩频系统及其Simulink仿真 总被引:2,自引:1,他引:2
介绍软扩频系统和里德-索罗门编码的基本原理,提出一种基于里德-索罗门码序列的软扩频系统,并且用Simulink仿真工具对该系统进行了建模。为了验证系统的抗干扰性能,对其进行了仿真分析,给出了这种软扩频系统和一般直扩频系统在单频干扰和宽带干扰下的误码率,仿真结果表明:这种基于里德.索罗门码序列的软扩频系统对单频信号干扰和宽带干扰有很好的抑制效果。 相似文献
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结合国际电联若干标准,在分析雷达对直接序列扩频(DSSS)系统干扰机理的基础上,对直接序列扩频系统在雷达脉冲干扰的误码率(BER)性能进行了推导,并通过仿真模型对在雷达长脉冲干扰和雷达短脉冲干扰下的误码率仿真分析,得到直接序列扩频系统抗雷达长短脉冲干扰的性能.文中的分析方法和结论对复杂电磁环境下电子对抗的研究有一定参考意义. 相似文献
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在扩频码采用理想随机序列和短周期序列两种情况下,对直接序列扩频系统在宽带噪声干扰、窄带噪声干扰和单频干扰下的抗干扰性能进行了分析和比较,并仿真验证,分析结果对军用扩频系统的设计和应用有指导意义。 相似文献
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介绍了DS/BPSK扩频系统的基本原理,分析了单频干扰下的抗干扰性能,给出了单频干扰DS/BPSK扩频系统的最佳频率位置,建立了基于Simulink的单频干扰下的DS/BPSK扩频系统仿真模型,通过Simulink仿真分析,给出了单频干扰下系统各个阶段的频谱图及不同信噪比下的误码率,仿真结果表明:该方法对DS/BPSK扩频信号中心频率区域的干扰效果极其明显. 相似文献
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针对将直扩(direct spread, DS)与收发多天线(multiple input multiple output, MIMO)空时分组编码相结合存在多址干扰,且受到宽带干扰尤其强干扰时性能会恶化,提出一种叠加扩频的方法来消除多址干扰,并利用子空间分解(subspace projection, SP)的方法实现对宽带干扰的抑制,即将信道和接收矩阵投影到干噪子空间中构建等效矩阵进行译码,其中通过简化的最大比合并译码降低了空时分组译码复杂度。理论分析及仿真表明该抗干扰方案能够提高DS抗窄带干扰能力,并实现抗宽带干扰和对多址干扰的完全抑制。 相似文献
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扩跳频通信技术以其良好的抗干扰能力广泛地应用于现代军事与民用通信中,但其频谱效率不够高。因此本文给出了一种信息驱动扩跳频(MD-DS/FH)通信系统模型,即在发射机中的跳频图案不再由传统的跳频码发生器驱动,而由所传输的部分信息数据来代替,并且接收机釆用包络检测器对载波频率进行盲检测。本文推导了AWGN与Rayleigh衰落信道下系统的误比特率公式,给出了闭合表达式,并通过仿真验证了理论推导的正确性。理论分析与仿真结果表明,所给通信系统在提高扩跳频通信系统频谱效率的同时,也提高了系统的误比特率和抗阻塞噪声干扰性能。 相似文献
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多载波频率分集扩展频谱码分多址通信(FD/SSMA)系统是一种基于多载波传输、利用与直接序列扩扩展频谱码分多址系统(DS/SSMA)的时间-频率对偶关系而提出的新的扩展频谱多址方案。本文给出了FD/SSMA系统的基本原理,分析了在加性高斯白噪声信道下FD/SSMA的多址性能和抗单频干扰能力,并通过高斯近似法和Monte-Carlo模拟方法得到了系统的平均误比特率。 相似文献
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DS/FH/TH混合扩频系统抗干扰性能的计算机模拟 总被引:1,自引:0,他引:1
在扩频通信中,抗干扰性能是评价扩频通信体制优劣的重要指标。本文研究DS/FH/TH混合扩频系统的抗干扰性能,建立了系统模型及计算机模拟方案,通过计算机模拟获得了在连续波、脉冲波多音干扰、部分带宽干扰、脉冲噪声干扰情况下的系统误码率曲线,具有一定的实用价值。 相似文献
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Glisic S.G. Mammela A. Kaasila V.-P. Pajkovic M.D. 《Communications, IEEE Transactions on》1995,43(1):136-145
It is already known that the performance of narrowband interference adaptive filtering in DS spread spectrum systems is additionally degraded in the presence of a frequency hopped jamming signal compared to the case with CW interference. Even so, the adaptive filter can be rather efficient because during the hopping interval, while the jamming signal parameters are constant, the filter adjusts its weights; and if the hopping rate is not too high, there are time periods when the interfering signal is suppressed. In order to have a better insight into the performance of these systems, we analyze the DS spread spectrum receiver behavior, when the jamming signal frequency is continuously changing (chirp signal). We find that this is a reasonable step for a jammer that is trying to be more efficient. In such a case, a two-sided filter structure shows worse overall performance than a prediction error structure. As the jamming frequency sweeping rate or bandwidth is increased, the system performance is degraded. The analysis provides an insight into how much the system performance will be degraded as a function of the interfering (frequency sweeping) signal parameters 相似文献
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《Wireless Communications, IEEE Transactions on》2003,2(5):1079-1089
Land mobile communication using satellites has become widespread. However, estimation of its average bit-error rate is still challenging due to the complexity of various system components, such as the nonlinearity of traveling wave tube amplifiers (TWTAs), intersymbol interference, spread spectrum under fading, or jamming conditions. The analytical approach using closed form solutions is very difficult if not impossible. Monte Carlo (MC) simulation can offer an alternative method of performance estimation; however, the use of MC simulation is often limited by an excessive computational burden. Importance sampling (IS) is an efficient simulation method that can greatly reduce this computational overhead although it requires additional modeling and a careful biasing scheme. We propose an integrated IS model which combines error event simulation, a conditional IS method, and an asymptotically efficient method for the effective estimation of the error rate. Simulation results conditioned on different channel parameters such as the backoff of a TWTA, jamming signal strength, and elevation angle of the low-Earth orbit satellite are provided. Comparisons between the proposed method and the MC method show that a great reduction in simulation time, as well as increased accuracy, can be achieved with the IS method. 相似文献
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The results of a Monte Carlo/semianalytic estimation of the performance of DS spread spectrum ISM band radio LANs in a time dispersive channel are presented. The results show that these DS systems have an advantage over FH systems of 4-6 times, depending on diversity scheme, in maximum tolerable delay spread or maximum transmission rate.<> 相似文献