低密度奇偶校验(Low density parity check,LDPC)跳码可以在物理层基于跳变的校验矩阵进行差错控制编译码。准循环低密度奇偶校验码(Quasi-cyclic low density parity check code,QC-LDPC)因其良好的纠错性能和易于工程实现的优点而得...低密度奇偶校验(Low density parity check,LDPC)跳码可以在物理层基于跳变的校验矩阵进行差错控制编译码。准循环低密度奇偶校验码(Quasi-cyclic low density parity check code,QC-LDPC)因其良好的纠错性能和易于工程实现的优点而得到广泛应用。本文提出了一种简单且易于工程实现的QC-LDPC跳码设计方法。首先采用有限域的两类子群设计跳变的基矩阵,再通过基模图码的外信息转移算法对基矩阵散列的校验矩阵进行掩模,使跳变矩阵具有统一架构和快速编码结构。仿真和分析表明,设计的QC-LDPC跳码具有超大的跳变码集和良好的纠错性能,码集中LDPC码数目可达1034个,随着码长增加,码集中的LDPC码数目呈指数倍增加,其平均性能可与诸多协议中的LDPC码相当,可用于提升通信系统的可靠性和安全性。展开更多
We investigate the problem of resource allocation in a downlink orthogonal frequency-division multiple access （OFDMA） broadband network with an eavesdropper under the condition that both legitimate users and the eav...We investigate the problem of resource allocation in a downlink orthogonal frequency-division multiple access （OFDMA） broadband network with an eavesdropper under the condition that both legitimate users and the eavesdropper are with imperfect channel state information （CSI）. We consider three kinds of imperfect CSI： （1） noise and channel estimation errors, （2） feedback delay and channel prediction, and （3） limited feedback channel capacity, where quantized CSI is studied using rate-distortion theory because it can be used to establish an information-theoretic lower bound on the capacity of the feedback channel. The problem is formulated as joint power and subcarrier allocation to optimize the maximum-minimum （max-min） fairness criterion over the users＇ secrecy rate. The problem considered is a mixed integer nonlinear programming problem. To reduce the complexity, we propose a two-step suboptimal algorithm that separately performs power and subcarrier allocation. For a given subcarrier assignment, optimal power allocation is achieved by developing an algorithm of polynomial computational complexity. Numerical results show that our proposed algorithm can approximate the optimal solution.展开更多
文摘低密度奇偶校验(Low density parity check,LDPC)跳码可以在物理层基于跳变的校验矩阵进行差错控制编译码。准循环低密度奇偶校验码(Quasi-cyclic low density parity check code,QC-LDPC)因其良好的纠错性能和易于工程实现的优点而得到广泛应用。本文提出了一种简单且易于工程实现的QC-LDPC跳码设计方法。首先采用有限域的两类子群设计跳变的基矩阵,再通过基模图码的外信息转移算法对基矩阵散列的校验矩阵进行掩模,使跳变矩阵具有统一架构和快速编码结构。仿真和分析表明,设计的QC-LDPC跳码具有超大的跳变码集和良好的纠错性能,码集中LDPC码数目可达1034个,随着码长增加,码集中的LDPC码数目呈指数倍增加,其平均性能可与诸多协议中的LDPC码相当,可用于提升通信系统的可靠性和安全性。
基金Project supported by the National Natural Science Foundation of China(Nos.61471008,61622101,and 61571020)the National Key Research and Development Program of China(No.2016YFE0123100)
文摘We investigate the problem of resource allocation in a downlink orthogonal frequency-division multiple access （OFDMA） broadband network with an eavesdropper under the condition that both legitimate users and the eavesdropper are with imperfect channel state information （CSI）. We consider three kinds of imperfect CSI： （1） noise and channel estimation errors, （2） feedback delay and channel prediction, and （3） limited feedback channel capacity, where quantized CSI is studied using rate-distortion theory because it can be used to establish an information-theoretic lower bound on the capacity of the feedback channel. The problem is formulated as joint power and subcarrier allocation to optimize the maximum-minimum （max-min） fairness criterion over the users＇ secrecy rate. The problem considered is a mixed integer nonlinear programming problem. To reduce the complexity, we propose a two-step suboptimal algorithm that separately performs power and subcarrier allocation. For a given subcarrier assignment, optimal power allocation is achieved by developing an algorithm of polynomial computational complexity. Numerical results show that our proposed algorithm can approximate the optimal solution.
