In this paper,the functions and the architecture of an ATM exchange are summarized.The switching fabrics,the line interface module and the control module are discussed in de-tail.An ATM switching system that adopts th...In this paper,the functions and the architecture of an ATM exchange are summarized.The switching fabrics,the line interface module and the control module are discussed in de-tail.An ATM switching system that adopts the scheme described in this paper has been de-veloped.展开更多
Abstract:Because of the speed limitation of the conventional bit-selection strategy in the existing weighted bit flipping algorithms,a highspeed Low-Density Parity-Check(LDPC)decoder cannot be realised.To solve this p...Abstract:Because of the speed limitation of the conventional bit-selection strategy in the existing weighted bit flipping algorithms,a highspeed Low-Density Parity-Check(LDPC)decoder cannot be realised.To solve this problem,we propose a fast weighted bit flipping algorithm.Specifically,based on the identically distributed error bits,a parallel bit-selection method is proposed to reduce the selection delay of the flipped bits.The delay analysis demonstrates that,the decoding speed of LDPC codes can be significantly improved by the proposed algorithm.Furthermore,simulation results verify the validity of the proposed algorithm.展开更多
This paper proposes a new multispectral image data compression algorithm (KLT/WT-3DEZB). The proposed coding strategy consists of three main steps. Firstly, a wavelet transform (WT) is applied to reduce the spatial re...This paper proposes a new multispectral image data compression algorithm (KLT/WT-3DEZB). The proposed coding strategy consists of three main steps. Firstly, a wavelet transform (WT) is applied to reduce the spatial redundancies. Then, a Karhunen-Loeve transform (KLT) is used to reduce the redundancies in the spectral domain. Finally, a modified SPECK algorithm-three-dimensional embedded zeroblock (3DEZB) algorithm is proposed and used to encode the transformed coefficients. Numerical experiments show that the reconstructed images using the proposed algorithm exhibite a better quality and a higher compression ratio than those obtained by traditional KLT/WT-3DSPIHT, 3DSPIHT, and 3DSPECK algorithms.展开更多
A new method for error detection using mode information of macroblocks （MBs） is proposed. For decodable inter MBs, inter residues are calculated by adding up absolute values of received residual pixels and intra com...A new method for error detection using mode information of macroblocks （MBs） is proposed. For decodable inter MBs, inter residues are calculated by adding up absolute values of received residual pixels and intra complexities are estimated by that of motion compensated reference blocks. If inter residues are larger than intra complexities by a predefined quantity, MBs are considered to be erroneous. For decodable intra MBs, the connective smoothness of the current MB with correctly decoded neighboring MBs is tested to find erroneous MBs. Combined with error concealment, the new method improves the quality of reconstructed images by about 0.5-1 dB in peak signal-noise ratio （PSNR）.展开更多
基金the High Technology Research and Development Programme of china.
文摘In this paper,the functions and the architecture of an ATM exchange are summarized.The switching fabrics,the line interface module and the control module are discussed in de-tail.An ATM switching system that adopts the scheme described in this paper has been de-veloped.
基金supported in part by the National Natural Science Foundation of China under Grant No.61072069the Fundamental Research Funds for the Central Universities under Grant No.72001859+1 种基金the Important National Science and Technology Specific Projects under Grant No.2011ZX03003-001-04the One Church,One Family,One Purpose Project(111 Project)under Grant No.B08038
文摘Abstract:Because of the speed limitation of the conventional bit-selection strategy in the existing weighted bit flipping algorithms,a highspeed Low-Density Parity-Check(LDPC)decoder cannot be realised.To solve this problem,we propose a fast weighted bit flipping algorithm.Specifically,based on the identically distributed error bits,a parallel bit-selection method is proposed to reduce the selection delay of the flipped bits.The delay analysis demonstrates that,the decoding speed of LDPC codes can be significantly improved by the proposed algorithm.Furthermore,simulation results verify the validity of the proposed algorithm.
基金This work was supported by the Advanced Program of Military Communications Technology under Grant No. 410010302.
文摘This paper proposes a new multispectral image data compression algorithm (KLT/WT-3DEZB). The proposed coding strategy consists of three main steps. Firstly, a wavelet transform (WT) is applied to reduce the spatial redundancies. Then, a Karhunen-Loeve transform (KLT) is used to reduce the redundancies in the spectral domain. Finally, a modified SPECK algorithm-three-dimensional embedded zeroblock (3DEZB) algorithm is proposed and used to encode the transformed coefficients. Numerical experiments show that the reconstructed images using the proposed algorithm exhibite a better quality and a higher compression ratio than those obtained by traditional KLT/WT-3DSPIHT, 3DSPIHT, and 3DSPECK algorithms.
基金This work was supported by the National Natural Sci-ence Foundation of China (No. 60372043, 60272050).
文摘A new method for error detection using mode information of macroblocks （MBs） is proposed. For decodable inter MBs, inter residues are calculated by adding up absolute values of received residual pixels and intra complexities are estimated by that of motion compensated reference blocks. If inter residues are larger than intra complexities by a predefined quantity, MBs are considered to be erroneous. For decodable intra MBs, the connective smoothness of the current MB with correctly decoded neighboring MBs is tested to find erroneous MBs. Combined with error concealment, the new method improves the quality of reconstructed images by about 0.5-1 dB in peak signal-noise ratio （PSNR）.
