The soft cancellation decoding of polar codes achieves a better performance than the belief propagation decoding with lower computational time and space complexities.However,because the soft cancellation decoding is b...The soft cancellation decoding of polar codes achieves a better performance than the belief propagation decoding with lower computational time and space complexities.However,because the soft cancellation decoding is based on the successive cancellation decoding,the decoding efficiency and performance with finite-length blocks can be further improved.Exploiting the idea of the successive cancellation list decoding,the soft cancellation decoding can be improved in two aspects:one is by adding branch decoding to the error-prone information bits to increase the accuracy of the soft information,and the other is through using partial iterative decoding to reduce the time and computational complexities.Compared with the original method,the improved soft cancellation decoding makes progress in the error correction performance,increasing the decoding efficiency and reducing the computational complexity,at the cost of a small increase of space complexity.展开更多
Relay transmission technique can be utilized to increase coverage or enhance throughput for conventional cellular communication systems. There are two typical relaying schemes： amplify-and- forward （AF） and decode-...Relay transmission technique can be utilized to increase coverage or enhance throughput for conventional cellular communication systems. There are two typical relaying schemes： amplify-and- forward （AF） and decode-and-forward （DF）. This paper presents a new scheme named soft symbol Estimation and Forward （SEF） , which holds the advantages of both AF and DF, i.e. keeping soft information and obtaining decoding gain. This scheme has similar operations as DF except that the operations are performed in a soft-input-soft-output （SISO） fashion. The relay performs SISO deco- ding, SISO re-encoding and key point soft symbol estimation, which is derived based on the maxi- mum likelihood （ML） criteria. Simulation results prove that the proposed SEF scheme much outper- forms both AF and DF.展开更多
A computationally efficient soft-output detector with lattice-reduction （LR） for the multiple-input multiple-output （MIMO） systems is proposed. In the proposed scheme, the sorted QR de- composition is applied on t...A computationally efficient soft-output detector with lattice-reduction （LR） for the multiple-input multiple-output （MIMO） systems is proposed. In the proposed scheme, the sorted QR de- composition is applied on the lattice-reduced equivalent channel to obtain the tree structure. With the aid of the boundary control, the stack algorithm searches a small part of the whole search tree to generate a handful of candidate lists in the reduced lattice. The proposed soft-output algorithm achieves near-optimal perfor- mance in a coded MIMO system and the associated computational complexity is substantially lower than that of previously proposed methods.展开更多
实际化工工业过程数据往往存在多重共线性、高度非线性等多重特性,这会严重影响传统软测量模型对关键质量变量的预测精度。针对这一局限性,提出了一种分布式非线性映射和并行输入的双向长短记忆(distributed nonlinear mapping and para...实际化工工业过程数据往往存在多重共线性、高度非线性等多重特性,这会严重影响传统软测量模型对关键质量变量的预测精度。针对这一局限性,提出了一种分布式非线性映射和并行输入的双向长短记忆(distributed nonlinear mapping and parallel input bidirectional long short-term memory,DNMPI-BiLSTM)软测量模型。在所提策略中,首先为了阐述过程变量与质量变量之间的关联性,采用互信息以及最大相关最小冗余方法对输入数据集进行分类。随后,为了充分挖掘工业过程内部所包含的高度复杂的非线性关系,利用深度极限学习机的隐藏层对子过程变量空间进行非线性映射到高维空间。最后,将三类数据的非线性映射结果并行,建立了基于分布式非线性映射和并行输入的DNMPI-BiLSTM软测量模型,以提升模型对复杂工业过程质量变量的预测能力。通过三个工业案例验证所提方法的有效性,仿真结果表明,所提出的基于分布式非线性映射和并行输入的BiLSTM软测量建模方法的预测精度优于其他先进模型。展开更多
为了提升包含CLLLC与DAB多模块混联结构的输入串联输出并联(Input Series Output Parallel,ISOP)型直流变压器的性能,构建了一种基于软开关特性与电压偏移约束的子模块配比设计方法。首先分析了CLLLC与DAB两类变换器的工作特性与软开关...为了提升包含CLLLC与DAB多模块混联结构的输入串联输出并联(Input Series Output Parallel,ISOP)型直流变压器的性能,构建了一种基于软开关特性与电压偏移约束的子模块配比设计方法。首先分析了CLLLC与DAB两类变换器的工作特性与软开关条件,明确在混合拓扑中分别采用CLLLC模块的定频开环控制以提升效率,DAB模块的单移相控制以实现功率调节。针对母线电压波动可能导致的软开关失效与器件过压问题,构建了以软开关可行性与器件电压偏移限制为核心的模块配比联合约束模型,并据此推导出保证系统高效与安全运行的子模块数量配比判据。最后通过MATLAB/Simulink平台仿真验证了对该混合拓扑分析与设计的可行性与正确性。展开更多
为了降低Turbo均衡中均衡器的复杂度,该文提出了符号方差反馈均衡算法(SVFE)。该算法是对精确的线性最小均方误差估计值(LMMSE)进行Taylor展开得到的。在该算法中,先利用时不变均衡器得到初步符号估计值,再根据先验符号方差对估计值加权...为了降低Turbo均衡中均衡器的复杂度,该文提出了符号方差反馈均衡算法(SVFE)。该算法是对精确的线性最小均方误差估计值(LMMSE)进行Taylor展开得到的。在该算法中,先利用时不变均衡器得到初步符号估计值,再根据先验符号方差对估计值加权,最后进行时不变滤波得到更佳的符号估计值。由于用到了时变的先验符号方差信息,其性能更接近精确的LMMSE均衡器。将所提算法用于Proakis C信道下的Turbo均衡处理,和时不变均衡算法进行仿真对比,所提算法将信噪比损失从0.83 d B降到了0.17 d B,并且仍可通过快速傅里叶变换降低为对数复杂度。展开更多
文摘The soft cancellation decoding of polar codes achieves a better performance than the belief propagation decoding with lower computational time and space complexities.However,because the soft cancellation decoding is based on the successive cancellation decoding,the decoding efficiency and performance with finite-length blocks can be further improved.Exploiting the idea of the successive cancellation list decoding,the soft cancellation decoding can be improved in two aspects:one is by adding branch decoding to the error-prone information bits to increase the accuracy of the soft information,and the other is through using partial iterative decoding to reduce the time and computational complexities.Compared with the original method,the improved soft cancellation decoding makes progress in the error correction performance,increasing the decoding efficiency and reducing the computational complexity,at the cost of a small increase of space complexity.
文摘Relay transmission technique can be utilized to increase coverage or enhance throughput for conventional cellular communication systems. There are two typical relaying schemes： amplify-and- forward （AF） and decode-and-forward （DF）. This paper presents a new scheme named soft symbol Estimation and Forward （SEF） , which holds the advantages of both AF and DF, i.e. keeping soft information and obtaining decoding gain. This scheme has similar operations as DF except that the operations are performed in a soft-input-soft-output （SISO） fashion. The relay performs SISO deco- ding, SISO re-encoding and key point soft symbol estimation, which is derived based on the maxi- mum likelihood （ML） criteria. Simulation results prove that the proposed SEF scheme much outper- forms both AF and DF.
文摘A computationally efficient soft-output detector with lattice-reduction （LR） for the multiple-input multiple-output （MIMO） systems is proposed. In the proposed scheme, the sorted QR de- composition is applied on the lattice-reduced equivalent channel to obtain the tree structure. With the aid of the boundary control, the stack algorithm searches a small part of the whole search tree to generate a handful of candidate lists in the reduced lattice. The proposed soft-output algorithm achieves near-optimal perfor- mance in a coded MIMO system and the associated computational complexity is substantially lower than that of previously proposed methods.
文摘实际化工工业过程数据往往存在多重共线性、高度非线性等多重特性,这会严重影响传统软测量模型对关键质量变量的预测精度。针对这一局限性,提出了一种分布式非线性映射和并行输入的双向长短记忆(distributed nonlinear mapping and parallel input bidirectional long short-term memory,DNMPI-BiLSTM)软测量模型。在所提策略中,首先为了阐述过程变量与质量变量之间的关联性,采用互信息以及最大相关最小冗余方法对输入数据集进行分类。随后,为了充分挖掘工业过程内部所包含的高度复杂的非线性关系,利用深度极限学习机的隐藏层对子过程变量空间进行非线性映射到高维空间。最后,将三类数据的非线性映射结果并行,建立了基于分布式非线性映射和并行输入的DNMPI-BiLSTM软测量模型,以提升模型对复杂工业过程质量变量的预测能力。通过三个工业案例验证所提方法的有效性,仿真结果表明,所提出的基于分布式非线性映射和并行输入的BiLSTM软测量建模方法的预测精度优于其他先进模型。
文摘为了提升包含CLLLC与DAB多模块混联结构的输入串联输出并联(Input Series Output Parallel,ISOP)型直流变压器的性能,构建了一种基于软开关特性与电压偏移约束的子模块配比设计方法。首先分析了CLLLC与DAB两类变换器的工作特性与软开关条件,明确在混合拓扑中分别采用CLLLC模块的定频开环控制以提升效率,DAB模块的单移相控制以实现功率调节。针对母线电压波动可能导致的软开关失效与器件过压问题,构建了以软开关可行性与器件电压偏移限制为核心的模块配比联合约束模型,并据此推导出保证系统高效与安全运行的子模块数量配比判据。最后通过MATLAB/Simulink平台仿真验证了对该混合拓扑分析与设计的可行性与正确性。
文摘为了降低Turbo均衡中均衡器的复杂度,该文提出了符号方差反馈均衡算法(SVFE)。该算法是对精确的线性最小均方误差估计值(LMMSE)进行Taylor展开得到的。在该算法中,先利用时不变均衡器得到初步符号估计值,再根据先验符号方差对估计值加权,最后进行时不变滤波得到更佳的符号估计值。由于用到了时变的先验符号方差信息,其性能更接近精确的LMMSE均衡器。将所提算法用于Proakis C信道下的Turbo均衡处理,和时不变均衡算法进行仿真对比,所提算法将信噪比损失从0.83 d B降到了0.17 d B,并且仍可通过快速傅里叶变换降低为对数复杂度。
