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OFDM系统非规则LDPC码优化设计 被引量:1
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作者 温娜 路唯佳 +2 位作者 刘翔 张平 陶晓峰 《北京邮电大学学报》 EI CAS CSCD 北大核心 2006年第4期107-110,共4页
提出了一种简单的非规则低密度校验码(LDPC)的优化设计方案.该方案充分考虑了正交频分复用(OFDM)信道的衰落特性,并利用LDPC码迭代译码原理,在衰落较大的子信道传输具有较高节点度的信息比特,在衰落较小的子信道传输具有较低节点度的信... 提出了一种简单的非规则低密度校验码(LDPC)的优化设计方案.该方案充分考虑了正交频分复用(OFDM)信道的衰落特性,并利用LDPC码迭代译码原理,在衰落较大的子信道传输具有较高节点度的信息比特,在衰落较小的子信道传输具有较低节点度的信息比特.仿真结果表明,当码长为1 024,码率为1/2时,该方案与规则码相比,在误比特率为10-5时可以节省3 dB,且降低了设计最优码的复杂度. 展开更多
关键词 低密度校验 正交频分复用 码优化设计
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Optimal design of coded aperture used for Z-Pinch driven fusion neutron imaging
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作者 JIA QingGang HU HuaSi +5 位作者 ZHENG XiangYang ZHANG FengNa WANG DongMing HU Guang ZHANG TianKui WU YueLei 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2015年第7期1289-1293,共5页
Currently,the neutron yield of Z-Pinch is lower than that of laser driven fusion.In the neutron imaging for this facility,the signal to noise ratio(SNR)has a significant influence on the expected spatial resolution of... Currently,the neutron yield of Z-Pinch is lower than that of laser driven fusion.In the neutron imaging for this facility,the signal to noise ratio(SNR)has a significant influence on the expected spatial resolution of the reconstructed fusion core,especially in the condition of low neutron yield.In this paper,mathematical model is purposed to describe the dependence of aperture parameters on the imaging SNR.The investigation shows that the imaging SNR is closely related to the size of contrast boundary on the point spread function.According to this,a novel non-uniform redundancy penumbra apertures array is designed.In addition,the imaging performances of this novel coded aperture,penumbra aperture and ring aperture are evaluated and compared by Monte Carlo method.The comparison shows that this novel aperture has significant advantage compared to the penumbra aperture which is commonly used for neutron imaging with low yield.The encouraging results can provide reference for the optimal design of the coded aperture used in the neutron imaging for Z-pinch driven fusion with low neutron yield. 展开更多
关键词 Z-pinch driven fusion neutron imaging coded aperture signal to noise ratio low neutron yield
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