通过定义有限域间的映射关系,提出了一种低复杂度的多元准循环奇偶校验码(QC-LDPC)的构造方法。利用这种方法可将较高阶数有限域的校验矩阵映射到指定的较低有限域上,且能保持原矩阵的结构性与稀疏特性。所构造的多元LDPC码不仅具有较...通过定义有限域间的映射关系,提出了一种低复杂度的多元准循环奇偶校验码(QC-LDPC)的构造方法。利用这种方法可将较高阶数有限域的校验矩阵映射到指定的较低有限域上,且能保持原矩阵的结构性与稀疏特性。所构造的多元LDPC码不仅具有较低的译码复杂度且具有准循环特性,在硬件上也易于用移位寄存器实现。在高斯白噪声(AWGN)信道下的仿真结果表明,所构造的多元QC-LDPC码具有良好的编译码性能。当误码率为10^(-6)时,码率为0.765的QC-LDPC码在目标域GF(8)上能获得0.2 d B的性能增益。展开更多
A low-complexity algorithm is proposed in this paper in order to optimize irregular low-density parity-check （LDPC） codes.The algorithm proposed can calculate the noise threshold by means of a one-dimensional densit...A low-complexity algorithm is proposed in this paper in order to optimize irregular low-density parity-check （LDPC） codes.The algorithm proposed can calculate the noise threshold by means of a one-dimensional density evolution and search the optimal degree profiles with fast-convergence differential evolution,so that it has a lower complexity and a faster convergence speed.Simulation resuits show that the irregular LDPC codes optimized by the presented algorithm can also perform better than Turbo codes at moderate block length even with less computation cost.展开更多
By exploiting the structural features of L1C messages,a novel Early Termination( ET) strategy is proposed to speed up the decoding of low-density parity-check( LDPC) codes in the GPS system. The proposed strategy is b...By exploiting the structural features of L1C messages,a novel Early Termination( ET) strategy is proposed to speed up the decoding of low-density parity-check( LDPC) codes in the GPS system. The proposed strategy is based on the cyclic redundancy check( CRC) of the messages in the subframes 2 and 3. The simulation results show that average number of iterations of the proposed strategy is less than that of the standard ET strategy,with nearly no degradation in decoding performance. Besides,the proposed ET strategy can be efficiently implemented in a sequential or parallel manner. Thus,the proposed ET strategy is attractive for practical purposes.展开更多
在介绍 L DPC (L ow Density Parity Code)低密度校验码的基本原理的基础上 ,针对任意离散无记忆信道的传输 ,从两个方面对其结构进行了改进。这种改进的 L DPC码是定义在有限域 GF(q)上的非正则 L DPC码 ,较之正则 L DPC码具有更好的...在介绍 L DPC (L ow Density Parity Code)低密度校验码的基本原理的基础上 ,针对任意离散无记忆信道的传输 ,从两个方面对其结构进行了改进。这种改进的 L DPC码是定义在有限域 GF(q)上的非正则 L DPC码 ,较之正则 L DPC码具有更好的性能。采用改进的非正则 L DPC码 ,经过最大似然概率译码 ,能够实现以任意逼近任何离散无记忆信道容量的速率的可靠通信。同时 ,讨论了对应于这种码结构的实际的迭代译码方法 ,并简单介绍了这种改进的非正则 L DPC码在OFDM系统、压缩图像传输等方面的应用。展开更多
文摘通过定义有限域间的映射关系,提出了一种低复杂度的多元准循环奇偶校验码(QC-LDPC)的构造方法。利用这种方法可将较高阶数有限域的校验矩阵映射到指定的较低有限域上,且能保持原矩阵的结构性与稀疏特性。所构造的多元LDPC码不仅具有较低的译码复杂度且具有准循环特性,在硬件上也易于用移位寄存器实现。在高斯白噪声(AWGN)信道下的仿真结果表明,所构造的多元QC-LDPC码具有良好的编译码性能。当误码率为10^(-6)时,码率为0.765的QC-LDPC码在目标域GF(8)上能获得0.2 d B的性能增益。
基金Leading Academic Discipline Project of Shanghai Municipal Education Commission,China(No.J51801)Shanghai Second Polytechnic University Foundation,China(No.QD209008)Leading Academic Discipline Project of Shanghai Second Polytechnic University,China(No.XXKZD1302)
文摘A low-complexity algorithm is proposed in this paper in order to optimize irregular low-density parity-check （LDPC） codes.The algorithm proposed can calculate the noise threshold by means of a one-dimensional density evolution and search the optimal degree profiles with fast-convergence differential evolution,so that it has a lower complexity and a faster convergence speed.Simulation resuits show that the irregular LDPC codes optimized by the presented algorithm can also perform better than Turbo codes at moderate block length even with less computation cost.
基金Sponsored by the National Natural Science Foundation of China(Grant No.61271423)
文摘By exploiting the structural features of L1C messages,a novel Early Termination( ET) strategy is proposed to speed up the decoding of low-density parity-check( LDPC) codes in the GPS system. The proposed strategy is based on the cyclic redundancy check( CRC) of the messages in the subframes 2 and 3. The simulation results show that average number of iterations of the proposed strategy is less than that of the standard ET strategy,with nearly no degradation in decoding performance. Besides,the proposed ET strategy can be efficiently implemented in a sequential or parallel manner. Thus,the proposed ET strategy is attractive for practical purposes.
文摘在介绍 L DPC (L ow Density Parity Code)低密度校验码的基本原理的基础上 ,针对任意离散无记忆信道的传输 ,从两个方面对其结构进行了改进。这种改进的 L DPC码是定义在有限域 GF(q)上的非正则 L DPC码 ,较之正则 L DPC码具有更好的性能。采用改进的非正则 L DPC码 ,经过最大似然概率译码 ,能够实现以任意逼近任何离散无记忆信道容量的速率的可靠通信。同时 ,讨论了对应于这种码结构的实际的迭代译码方法 ,并简单介绍了这种改进的非正则 L DPC码在OFDM系统、压缩图像传输等方面的应用。
