共查询到19条相似文献,搜索用时 125 毫秒
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粒子滤波是一种基于贝叶斯估计的算法,在信道盲辨识和盲均衡问题上具有快收敛、抗深衰信道等优势。Turbo盲均衡在低信噪比条件下有较好的误码性能。为了在深衰信道下使通信具有良好的误码性能,对粒子滤波盲均衡算法进行改进,改进算法的重要性采样函数利用了粒子的先验信息,得到一种软输入软输出的粒子滤波盲均衡算法。依据Turbo盲均衡的框架结构实现了一种基于粒子滤波的Turbo盲均衡算法,该算法利用信道编码带来的编码增益,提高了均衡和信道辨识的性能。仿真结果表明相比粒子滤波盲均衡算法本文提出算法的误码率性能提高1dB左右,误帧率性能则提高了3dB以上,经分析可知在信道系数估计较为准确的条件下,系统数据帧几乎没有误码。 相似文献
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在ε均衡概念基础上,提出了对含公零点SIMO信道的盲辨识算法。该算法充分利用发送符号属于有限字符集的先验知识,先直接盲检测发送序列,然后再进行信道辨识。仿真结果表明:不管信道是否包含公零点,本文提出的信道盲辨识ε算法性能都明显地优于基于二阶统计量的其它经典算法。 相似文献
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基于盲源分离的水声信道盲均衡处理方法 总被引:2,自引:1,他引:1
提出了一种基于盲源分离的水声信道讯均衡处理方法,通过对接收信号过采样构成源信号,采用了基于信息最大化原理(Infomax)在线分离算法进行了水声信道的盲均衡,并研究了时变水声信道条件下算法的均衡情况,仿真实验结果表明,该处理方法对多径水声信道具有较好的均衡效果,同时不受最小相位的条件限制。 相似文献
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小波建模在时变信道盲识别中的应用 总被引:1,自引:0,他引:1
当前的信道盲均衡与盲识别算法主要考虑的是线性时不变信道,而对于时变的信道,传统的自适应技术常忽略考虑相关的信道时变信息,从而不能很好地对信道进行均衡与识别,本文在考虑信道时变信息的同时,采用时变信道多分辨率分解小波模型对时变信道进行建模,并依此模型给出变信道的盲识别算法。 相似文献
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针对无线多径稀疏信道,利用信道有效近似思想,提出了一种改进的基于矩阵外积分解的信道盲辨识与盲均衡算法。算法首先利用改进的VIA信道阶数估计准则,对多径稀疏信道“有效部分”的阶数进行精确估计,然后利用改进的矩阵外积分解算法估计出信道冲激响应的“有效部分”,最后利用该估计结果对接收数据进行反卷积运算,恢复出发送信号。为了降低噪声以及信道冲激响应中的“零抽头”部分对信道盲辨识性能的影响,本算法对噪声方差估计方法进行了改进,提高了算法在中、低信噪比条件下的盲辨识性能。与现有算法相比,本算法不仅降低了对信噪比的要求,而且克服了基于LC准则的子空间算法(SSA, Subspace Algorithm)的相位偏转问题,其中噪声方差的估计方法也可应用于信噪比估计技术。仿真实验以及对SPIB微波信道测试结果验证了本文算法的有效性。 相似文献
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This paper proposes a dynamic Monte Carlo sampling method, called the conditional minimal cut set (COMICS) algorithm, where all arcs are not simulated at each trial and all minimal cut sets need not be given in advance. The proposed algorithm repeats simulating a minimal cut set composed of the arcs which originate from the (new) source node and reducing the network on the basis of the states of simulated arcs until the s-t connectedness is confirmed. We develop the importance sampling estimator, the total hazard estimator and the hazard importance sampling estimator which are all based on the proposed algorithm, and compare the performance of these simulation estimators. It is found that these estimators can significantly reduce the variance of the raw simulation estimator and the usual importance sampling estimator. 相似文献
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本文根据单通道接收两路MPSK混合信号在过采样下的基本模型,针对粒子滤波算法在单通道信号盲分离中的性能瓶颈以及高复杂度问题,提出了基于MCMC方法的新算法。该算法对接收信号进行过采样处理,能够利用更多的波形信息,从而有效抑制噪声的影响。新算法利用Gibbs采样估计MPSK调制符号的后验概率,近似实现了贝叶斯最优估计,并利用最小二乘法实现参数的迭代估计。理论分析与仿真实验表明,相对粒子滤波算法,本文提出的新算法在误码率性能以及复杂度方面具有良好的表现。 相似文献
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In order to obtain unknown symbol rate of incoming signal at a receiver, in this paper, cyclostationary features of linear digitally modulated signals are exploited by proposed periodic variation method. A low complexity but highly accurate symbol rate estimation technique is obtained. The proposed method is based on a superposed epoch analysis over autocorrelations obtained blindly in different sampling frequencies. The obtained autocorrelations are analyzed in the frequency domain, and it is seen that there are large oscillations when the autocorrelation is obtained around the symbol rate. Then, a superposed epoch analysis is developed in order to estimate symbol rate based of the periodic variations on the frequency responses of autocorrelations. The proposed algorithm is quite accurate in the noisy environment because the noise is having no frequency component after taking Fourier transform of autocorrelations in all sampling rates, and this feature is also valid for the offset frequency that the purposed estimation is not affected by offset frequency. Thus, a successful blind symbol rate estimation algorithm is obtained, and it performs much better error performance than those using the well‐known cyclic correlation based symbol rate estimations, as it is proven by the obtained performances presented in the paper. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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In continuous action tasks,deep reinforcement learning usually uses Gaussian distribution as a policy function.Aiming at the problem that the Gaussian distribution policy function slows down due to the clipped action,an importance sampling advantage estimator was proposed.Based on the general advantage estimator,an importance sampling mechanism was introduced by the estimator to improve the convergence speed of the algorithm and correct the deviation of the value function caused by calculating the target strategy and action strategy ratio of the boundary action.In addition,the L parameter was introduced by ISAE which improved the reliability of the sample and limited the stability of the network parameters by limiting the range of the importance sampling rate.In order to verify the effectiveness of the ISAE,applying it to proximal policy optimization and comparing it with other algorithms on the MuJoCo platform.Experimental results show that ISAE has a faster convergence rate. 相似文献
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本文针对恒模算法(CMA)收敛速度较慢、收敛后均方误差较大的缺点,提出一种新的双模式盲均衡算法。先采用T/4分数间隔采样的盲均衡算法,由于采用了过采样技术,避免了因欠采样引起的频谱混叠,然后在算法收敛后切换到判决引导(DD-LMS)算法,减少误码率。计算机仿真表明,本文提出的新算法有较快的收敛速度、较小的稳态误差和较低的误码率。 相似文献
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基于抛物线映射的混沌LT编码算法 总被引:3,自引:0,他引:3
该文提出一种基于抛物线映射和混沌置乱方法的LT编码算法。首先用混沌初始值作为密钥,采用抛物线映射产生混沌序列并转换为类均匀分布序列,再通过位置置乱算法生成LT码的度分布和度邻接数据序列,较传统的重要抽样方法具有更高的灵敏度,保留了理论分布的结构。实验结果表明,该算法具有实现结构简单、分组头部开销小、保密性好及高于传统重要抽样方法的性能。 相似文献