为了改善分布式存储系统的可靠性和修复效率,提出了一种基于图因子分解的部分重复(fractional repetition based on graph factorization,FRGF)码的构造算法。FRGF码能在大范围内选择构造参数和数据块的重复度,并且构造方法多样。与现...为了改善分布式存储系统的可靠性和修复效率,提出了一种基于图因子分解的部分重复(fractional repetition based on graph factorization,FRGF)码的构造算法。FRGF码能在大范围内选择构造参数和数据块的重复度,并且构造方法多样。与现有的里所(Read-Solomon,RS)码和简单再生码(simple regeneration codes,SRC)相比,FRGF码在修复局部性、修复复杂度及修复带宽等方面具有更低的开销,且修复效率高,显著减少了故障节点的修复时间。展开更多
A hybrid carrier (HC) DS CDMA communication system is proposed, combining 4-weighted fractional Fourier transform (4-WFRFT) with code division multiple access (CDMA) technique. The signals are modulated in a certain o...A hybrid carrier (HC) DS CDMA communication system is proposed, combining 4-weighted fractional Fourier transform (4-WFRFT) with code division multiple access (CDMA) technique. The signals are modulated in a certain order fractional Fourier domain and transformed by 4-WFRFT to compose the hybrid carrier signals. In the time domain CDMA technique is adopted for multiple accesses and time diversity gain. Compared to orthogonal frequency division multiplexing (OFDM) system, in which Fourier transform is adopted, the signal energy in HC system is distributed on the time-frequency plane more evenly and symmetrically. Thus, when there is a deep fading notch or single-frequency interference in the channel, the proposed method can split the interference to a broader range in order to reduce the influence, resulting in the better system performance. Moreover, the performances of the proposed system, such as peak-to-average power rate (PAPR) and security are also discussed in the paper.展开更多
为了满足分布式存储系统的动态存储和异构存储,本文提出一种基于节点共边的异构部分重复码(heterogeneous fractional repetition codes based on node common edge,HFRC-NCE)的构造算法.具体地,将MDS码编码后的数据块分为冷数据块和热...为了满足分布式存储系统的动态存储和异构存储,本文提出一种基于节点共边的异构部分重复码(heterogeneous fractional repetition codes based on node common edge,HFRC-NCE)的构造算法.具体地,将MDS码编码后的数据块分为冷数据块和热数据块,结合节点共边的特性,分别将冷数据块和热数据块复制不同的倍数存储到各个节点中,构造的异构部分重复码更加简单直观,可实现故障节点的精确无编码修复.理论分析表明,与基于完全图和部分正则图构造的部分重复码相比,基于节点共边的异构部分重复码虽然存储开销和修复带宽开销略大,但其节点修复选择度更高,节点存储数据容量更多样化,重构度更小.展开更多
针对部分重复码的有效修复问题,本文基于Harary图生成树构造出了一种新型的部分重复(Fractional Repetition based on Spanning trees of Harary graph,FRSH)码.实验结果表明,相较于现有的里所(Read-Solomon,RS)码和简单再生码(Simple R...针对部分重复码的有效修复问题,本文基于Harary图生成树构造出了一种新型的部分重复(Fractional Repetition based on Spanning trees of Harary graph,FRSH)码.实验结果表明,相较于现有的里所(Read-Solomon,RS)码和简单再生码(Simple Regeneration Codes,SRC),FRSH码在修复带宽开销、修复局部性等方面得到了更低的开销,且改善了修复效率,并将故障节点的修复时间缩短.展开更多
文摘为了改善分布式存储系统的可靠性和修复效率,提出了一种基于图因子分解的部分重复(fractional repetition based on graph factorization,FRGF)码的构造算法。FRGF码能在大范围内选择构造参数和数据块的重复度,并且构造方法多样。与现有的里所(Read-Solomon,RS)码和简单再生码(simple regeneration codes,SRC)相比,FRGF码在修复局部性、修复复杂度及修复带宽等方面具有更低的开销,且修复效率高,显著减少了故障节点的修复时间。
基金Sponsored by the National Natural Science Foundation General Program of China(Grant No.61171110)
文摘A hybrid carrier (HC) DS CDMA communication system is proposed, combining 4-weighted fractional Fourier transform (4-WFRFT) with code division multiple access (CDMA) technique. The signals are modulated in a certain order fractional Fourier domain and transformed by 4-WFRFT to compose the hybrid carrier signals. In the time domain CDMA technique is adopted for multiple accesses and time diversity gain. Compared to orthogonal frequency division multiplexing (OFDM) system, in which Fourier transform is adopted, the signal energy in HC system is distributed on the time-frequency plane more evenly and symmetrically. Thus, when there is a deep fading notch or single-frequency interference in the channel, the proposed method can split the interference to a broader range in order to reduce the influence, resulting in the better system performance. Moreover, the performances of the proposed system, such as peak-to-average power rate (PAPR) and security are also discussed in the paper.
文摘为了满足分布式存储系统的动态存储和异构存储,本文提出一种基于节点共边的异构部分重复码(heterogeneous fractional repetition codes based on node common edge,HFRC-NCE)的构造算法.具体地,将MDS码编码后的数据块分为冷数据块和热数据块,结合节点共边的特性,分别将冷数据块和热数据块复制不同的倍数存储到各个节点中,构造的异构部分重复码更加简单直观,可实现故障节点的精确无编码修复.理论分析表明,与基于完全图和部分正则图构造的部分重复码相比,基于节点共边的异构部分重复码虽然存储开销和修复带宽开销略大,但其节点修复选择度更高,节点存储数据容量更多样化,重构度更小.
文摘针对部分重复码的有效修复问题,本文基于Harary图生成树构造出了一种新型的部分重复(Fractional Repetition based on Spanning trees of Harary graph,FRSH)码.实验结果表明,相较于现有的里所(Read-Solomon,RS)码和简单再生码(Simple Regeneration Codes,SRC),FRSH码在修复带宽开销、修复局部性等方面得到了更低的开销,且改善了修复效率,并将故障节点的修复时间缩短.
