This paper presents a novel technique to significantly reduce the implementation complexity of Low-Density Parity-Check (LDPC) decoders. The proposed technique uses high precision soft messages at the variable nodes b...
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ISBN:
(纸本)9781424488650
This paper presents a novel technique to significantly reduce the implementation complexity of Low-Density Parity-Check (LDPC) decoders. The proposed technique uses high precision soft messages at the variable nodes but scales down the extrinsic message length, which reduces the number of interconnections between variable and check nodes. It also simplifies the check node operation. The effect on performance and complexity of the decoders due to such simplification is analyzed. A prototype model of the proposed decoders compliant with the WiMax application standard has been implemented and tested on Xilinx Virtex 5 FPGA. The implementation results show that the proposed decoders can achieve significant reduction in hardware complexity with comparable decoding performance to that of Min-Sum algorithm based decoders. The proposed decoders are estimated to achieve an average throughput in the range of 6 - 11 Gbps, even with short code lengths.
For the high-rise building with the basement,it is difficult to identify the position of the embedded fixed end due to the restraints of the backfill soil *** simplified mechanical model of the high-rise building with...
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For the high-rise building with the basement,it is difficult to identify the position of the embedded fixed end due to the restraints of the backfill soil *** simplified mechanical model of the high-rise building with the basement is established based on several hypotheses,and the mathematical expressions for calculating the elastic lateral displacement and internal forces of the high-rise building with the basement under the inverted-triangle distributed load is then obtained based on the mechanical *** influence of parameters β and h/H to four variable parameters are researched,and the four variable parameters are the moment M(0)and shear Q(0) at the bottom plate of the basement,the lateral displacement y(h) at the top plate of the basement,the lateral displacement y(H) at the top of the whole *** indicates that the simplified algorithms of the high-rise building with the basement considering the restraint of the backfill soil foundation are reliable,and can be referred and applied by the researchers and engineers.
In this paper, a simple and novel residual parameter extraction technique is provided for impedance substrate calibration standards. It uses the measured scattering parameters of four calibration standards, that is th...
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In this paper, a simple and novel residual parameter extraction technique is provided for impedance substrate calibration standards. It uses the measured scattering parameters of four calibration standards, that is the THRU, SHORT, OPEN, and LOAD standards, with only the DC resistance known in advance. Based on the electric structures and the frequency range of interest, the equivalent circuit of each standard is provided. The residual parameters in the equivalent circuits might show frequency dependence or frequency non-dependence, which are both considered in the following analysis. In the parameter extraction algorithm, no other calibration is needed. Instead, only the recorded raw data of the four standards are used, by assuming that the two ports of the SHORT, OPEN, and LOAD standards are symmetric and identical. A series of validation experiments are performed on a commercial calibration substrate, within the broad frequency range from 200 MHz to 110 GHz. The results have shown that the extracted residual parameters by using the proposed method are in very good consistency with the values provided by the manufacturer. In addition, the extracted parameters are further used for SOLT calibration, by measuring another group of calibration standards on the commercial calibration substrate. The calibration accuracy and reliability are further verified by using another open structure, a transmission line, and a mismatched load.
Continuous welded rail (CWR) has been used in high-speed railways in China. The bridge-rail interaction caused by temperature change when CWR is paved on cable-stayed bridges is studied in this paper. A bridge-rail in...
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Continuous welded rail (CWR) has been used in high-speed railways in China. The bridge-rail interaction caused by temperature change when CWR is paved on cable-stayed bridges is studied in this paper. A bridge-rail interaction model is first established using the finite element method. Based on the formulated model, the variation pattern of the force and displacement of rail and bridge-rail relative displacement due to temperature change is studied. The additional temperature forces experienced by stay cables and main towers are obtained, and the influence of the stiffness and temperature change of stay cables and main towers on the additional temperature force of rail is studied. Two simplified algorithms are proposed to facilitate the analysis of bridge-rail interaction. Results show that the distribution patterns of the additional temperature force and displacement of rail on the cable-stayed bridge are the same as those on a common bridge, and the forces experienced by stay cables and main towers are within the safety limit of bridge components. The stiffness variation of stay cables has more influence on the bridge-rail interaction than that of main towers. The distribution patterns of the forces and displacements obtained by the simplified algorithms are similar with those obtained by the FEM. The simplified algorithms can be used for the design of CWR laid on cable-stayed bridges.
A simplified algorithm for SAR-based bathymetry is presented able to measure surface current variations generated by the bottom topography from SAR intensity images and to reduce the need for both a-priori information...
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