对于多径稀疏的多输入多输出正交频分复用(Multiple-input and multiple-output orthogonal frequency di-vision multiplexing,MIMO-OFDM)信道,提出了基于广义Akaike信息论准则(Generalized Akaike informationcriterion,GAIC)的MIMO-O...对于多径稀疏的多输入多输出正交频分复用(Multiple-input and multiple-output orthogonal frequency di-vision multiplexing,MIMO-OFDM)信道,提出了基于广义Akaike信息论准则(Generalized Akaike informationcriterion,GAIC)的MIMO-OFDM系统实用的信道估计算法,该算法能够估计出信道的长度和每径信道的时延,降低加性白噪声对信道估计的影响,提高信道估计的精度。通过仿真,与最小二乘(Least squares,LS)算法和离散傅里叶变换(Discrete Fourier transform,DFT)算法相比较,大大地降低了信道的估计误差,提高了系统性能,且信道稀疏性越强,性能改善越好。展开更多
An exact solution of the vacuum Einstein＇s field equations is presented, in which there exists a congruence of null geodesics whose shear behaves like a travelling wave of the KdV equation. On the basis of this exact...An exact solution of the vacuum Einstein＇s field equations is presented, in which there exists a congruence of null geodesics whose shear behaves like a travelling wave of the KdV equation. On the basis of this exact solution, the feasibility of solitonic information transmission by exploiting the nonlinearity intrinsic to the Einstein field equations is discussed.展开更多
基金The project supported by National Natural Science Foundation of China under Grant Nos. 10231050 and 10375087, and National Key Basic Research Project of China under Grant Nos. 2004CB31800 and 2006CB805905
文摘An exact solution of the vacuum Einstein＇s field equations is presented, in which there exists a congruence of null geodesics whose shear behaves like a travelling wave of the KdV equation. On the basis of this exact solution, the feasibility of solitonic information transmission by exploiting the nonlinearity intrinsic to the Einstein field equations is discussed.
