为有效抑制电力线通信(power line communication,PLC)系统中的脉冲噪声,从信号被脉冲噪声影响后正态性被破坏的角度出发,文章提出一种基于广义幂变换的脉冲噪声抑制方法。该方法首先引入Box-Cox变换,通过对接收信号进行幂变换处理,使...为有效抑制电力线通信(power line communication,PLC)系统中的脉冲噪声,从信号被脉冲噪声影响后正态性被破坏的角度出发,文章提出一种基于广义幂变换的脉冲噪声抑制方法。该方法首先引入Box-Cox变换,通过对接收信号进行幂变换处理,使其分布更接近正态分布,又通过推导引入新的零记忆非线性(zero memory non-linearity,ZMNL)函数,以便进一步优化处理效果。此种结合ZMNL函数的Box-Cox变换可改善接收信号的正态性,实现对脉冲噪声的抑制。仿真结果验证所提广义幂变换方法对接收信号的正态性改善效果明显,对脉冲噪声有良好的抑制效果,并且与传统消隐法相比效果更好。展开更多
Given imperfect channel state information(CSI)and considering the interference from the primary transmitter,an underlay cognitive multisource multidestination relay network is proposed.A closed-form exact outage proba...Given imperfect channel state information(CSI)and considering the interference from the primary transmitter,an underlay cognitive multisource multidestination relay network is proposed.A closed-form exact outage probability and asymptotic outage probability are derived for the secondary system of the network.The results show that the outage probability is influenced by the source and destination number,the CSI imperfection as well as the interference from the primary transmitter,while the diversity order is independent of the CSI imperfection and the interference from the primary transmitter,yet it is equal to the minimum of the source and destination number.Moreover,extensive simulations are conducted with different system parameters to verify the theoretical analysis.展开更多
基于高阶奇异值分解(High Order Singular Value Decomposition,HOSVD)降噪的信道预测算法对天线数较少引起的秩不足问题比较敏感,同时也难以应付较大多普勒频移的情况,从而引起信道估计性能和预测性能的急剧下降、损失信道容量.针对这...基于高阶奇异值分解(High Order Singular Value Decomposition,HOSVD)降噪的信道预测算法对天线数较少引起的秩不足问题比较敏感,同时也难以应付较大多普勒频移的情况,从而引起信道估计性能和预测性能的急剧下降、损失信道容量.针对这一问题,提出了一种改进的使用HOSVD降噪的信道预测算法.该算法先利用多输入多输出(Multiple-input Multiple-Output,MIMO)信道固有的空时相关性对采样得到的信道状态信息(Channel State Information,CSI)进行矩阵重排和数据平滑处理,随后基于信道的多维结构特性,使用HOSVD降低噪声的影响,继而重构信道矩阵,最后利用递归最小二乘滤波器对未来时刻的信道状态进行预测.仿真表明,所提算法的估计误差和预测误差性能均明显优于对比算法,这是因为所提算法通过矩阵重排和空时平滑,虚拟地增加了天线数,降低了秩缺失问题对估计和预测精度的影响,从而有效补偿了因误差所致的信道容量的损失.同时,对比天线数和多普勒频移对不同算法性能的影响可见,所提算法也能在大多普勒频移和天线数较少等不利条件下提供较好预测性能和信道容量,具有一定的优越性.展开更多
脉冲噪声广泛存在于电力线通信(power line communication,PLC)系统中,会严重影响系统的通信性能。电力线脉冲噪声的建模通常使用α稳定分布模型,为达到最佳的脉冲噪声抑制效果,需要知道脉冲噪声的类型和相关参数。为此,文章提出一种基...脉冲噪声广泛存在于电力线通信(power line communication,PLC)系统中,会严重影响系统的通信性能。电力线脉冲噪声的建模通常使用α稳定分布模型,为达到最佳的脉冲噪声抑制效果,需要知道脉冲噪声的类型和相关参数。为此,文章提出一种基于混合神经网络的符合α稳定分布的脉冲噪声参数估计方法。不同于传统的方法,本方法可以分别独立地估计α稳定分布的重要参数α(即特征指数)和γ(即尺度参数)。仿真结果表明,与传统方法相比,提出的方法具有更准确的参数估计性能,归一化均方误差值仅为10–4左右。展开更多
In this paper, trellis shaping is applied to reducing the Peak-to-Average Power Ratio(PAPR) of NC-OFDM signals due to the fact that the total number of active subcarriers and their locations might change continuously ...In this paper, trellis shaping is applied to reducing the Peak-to-Average Power Ratio(PAPR) of NC-OFDM signals due to the fact that the total number of active subcarriers and their locations might change continuously in a dynamic spectrum access network.A new branch metric of trellis shaping is proposed which reduces the PAPR of OFDM signals through minimizing the variance of the power by VA decoder.The overall performance considerably depends on the type of signal mapping, and therefore a new type of 64QAM mapping method is designed.Simulation results show that this scheme significantly reduces the PAPR.Finally, a significant phenomenon is demonstrated that the PAPR of NC-OFDM signals in which the deactivated carriers is distributed in the Bernoulli distribution has better performance than that of OFDM signals.展开更多
文摘为有效抑制电力线通信(power line communication,PLC)系统中的脉冲噪声,从信号被脉冲噪声影响后正态性被破坏的角度出发,文章提出一种基于广义幂变换的脉冲噪声抑制方法。该方法首先引入Box-Cox变换,通过对接收信号进行幂变换处理,使其分布更接近正态分布,又通过推导引入新的零记忆非线性(zero memory non-linearity,ZMNL)函数,以便进一步优化处理效果。此种结合ZMNL函数的Box-Cox变换可改善接收信号的正态性,实现对脉冲噪声的抑制。仿真结果验证所提广义幂变换方法对接收信号的正态性改善效果明显,对脉冲噪声有良好的抑制效果,并且与传统消隐法相比效果更好。
基金Supported by the National Natural Science Foundation of China(No.61301170,61571340)the Fundamental Research Funds for the Central Universities(No.JB150109)the 111 Project(No.B08038)
文摘Given imperfect channel state information(CSI)and considering the interference from the primary transmitter,an underlay cognitive multisource multidestination relay network is proposed.A closed-form exact outage probability and asymptotic outage probability are derived for the secondary system of the network.The results show that the outage probability is influenced by the source and destination number,the CSI imperfection as well as the interference from the primary transmitter,while the diversity order is independent of the CSI imperfection and the interference from the primary transmitter,yet it is equal to the minimum of the source and destination number.Moreover,extensive simulations are conducted with different system parameters to verify the theoretical analysis.
文摘基于高阶奇异值分解(High Order Singular Value Decomposition,HOSVD)降噪的信道预测算法对天线数较少引起的秩不足问题比较敏感,同时也难以应付较大多普勒频移的情况,从而引起信道估计性能和预测性能的急剧下降、损失信道容量.针对这一问题,提出了一种改进的使用HOSVD降噪的信道预测算法.该算法先利用多输入多输出(Multiple-input Multiple-Output,MIMO)信道固有的空时相关性对采样得到的信道状态信息(Channel State Information,CSI)进行矩阵重排和数据平滑处理,随后基于信道的多维结构特性,使用HOSVD降低噪声的影响,继而重构信道矩阵,最后利用递归最小二乘滤波器对未来时刻的信道状态进行预测.仿真表明,所提算法的估计误差和预测误差性能均明显优于对比算法,这是因为所提算法通过矩阵重排和空时平滑,虚拟地增加了天线数,降低了秩缺失问题对估计和预测精度的影响,从而有效补偿了因误差所致的信道容量的损失.同时,对比天线数和多普勒频移对不同算法性能的影响可见,所提算法也能在大多普勒频移和天线数较少等不利条件下提供较好预测性能和信道容量,具有一定的优越性.
文摘脉冲噪声广泛存在于电力线通信(power line communication,PLC)系统中,会严重影响系统的通信性能。电力线脉冲噪声的建模通常使用α稳定分布模型,为达到最佳的脉冲噪声抑制效果,需要知道脉冲噪声的类型和相关参数。为此,文章提出一种基于混合神经网络的符合α稳定分布的脉冲噪声参数估计方法。不同于传统的方法,本方法可以分别独立地估计α稳定分布的重要参数α(即特征指数)和γ(即尺度参数)。仿真结果表明,与传统方法相比,提出的方法具有更准确的参数估计性能,归一化均方误差值仅为10–4左右。
基金Supported by the National Natural Science Foundation of China (No.60832008)National Basic Research Program of China (973 Program, No.2009CB320403)
文摘In this paper, trellis shaping is applied to reducing the Peak-to-Average Power Ratio(PAPR) of NC-OFDM signals due to the fact that the total number of active subcarriers and their locations might change continuously in a dynamic spectrum access network.A new branch metric of trellis shaping is proposed which reduces the PAPR of OFDM signals through minimizing the variance of the power by VA decoder.The overall performance considerably depends on the type of signal mapping, and therefore a new type of 64QAM mapping method is designed.Simulation results show that this scheme significantly reduces the PAPR.Finally, a significant phenomenon is demonstrated that the PAPR of NC-OFDM signals in which the deactivated carriers is distributed in the Bernoulli distribution has better performance than that of OFDM signals.
