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
复杂应用场景决定短距离无线通信系统面对多种干扰、较低硬件资源配置导致其抗干扰能力有限,为实现可靠传输,设计基于改进LDPC码的短距离跳频无线通信系统。其中,提出低复杂度校验和更新(LCU,low-complexity check sum updating)算法,...复杂应用场景决定短距离无线通信系统面对多种干扰、较低硬件资源配置导致其抗干扰能力有限,为实现可靠传输,设计基于改进LDPC码的短距离跳频无线通信系统。其中,提出低复杂度校验和更新(LCU,low-complexity check sum updating)算法,降低计算复杂度;提出基于MTBF(multi-threshold bit flipping)的LCU-MTBF算法,提高译码性能,降低译码复杂度。仿真结果表明,LCU算法适用于多种硬判决译码算法,在不影响原有算法性能的基础上降低译码算法的计算复杂度;LCU-MTBF在误码率(bit error rate)为10^(-5)、迭代次数为5时,获得0.15 d B性能增益,将MTBF算法中加法次数降低约40%;当误码率为10^(-4)、信噪比为15 d B时,在部分频带干扰和全频带干扰下,基于改进LDPC码的短距离跳频无线通信系统均获得7 d B左右的性能增益,有效改善其干扰性能。展开更多
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.
文摘复杂应用场景决定短距离无线通信系统面对多种干扰、较低硬件资源配置导致其抗干扰能力有限,为实现可靠传输,设计基于改进LDPC码的短距离跳频无线通信系统。其中,提出低复杂度校验和更新(LCU,low-complexity check sum updating)算法,降低计算复杂度;提出基于MTBF(multi-threshold bit flipping)的LCU-MTBF算法,提高译码性能,降低译码复杂度。仿真结果表明,LCU算法适用于多种硬判决译码算法,在不影响原有算法性能的基础上降低译码算法的计算复杂度;LCU-MTBF在误码率(bit error rate)为10^(-5)、迭代次数为5时,获得0.15 d B性能增益,将MTBF算法中加法次数降低约40%;当误码率为10^(-4)、信噪比为15 d B时,在部分频带干扰和全频带干扰下,基于改进LDPC码的短距离跳频无线通信系统均获得7 d B左右的性能增益,有效改善其干扰性能。
基金supported by the National Natural Science Foundation of China(Nos.61071117,61171158,61275077)the Natural Science Foundation Project of CQ CSTC(Nos.cstc2013jcyjA40052,cstc2012jjA40060)the Projects of the Education Council of Chongqing(No.KJ130515)
文摘战术数据链系统能够提高部队信息化作战能力,其中信道编码技术是保证消息传输可靠性的关键技术之一.构建了一种新的战术数据链系统,系统采用低密度奇偶校验(LDPC,Low-Density Parity-Check)码方案,LDPC码是适用于传输可靠性要求高的通信系统的新型码组.介绍了LDPC码方案中的和积算法,描述了系统的传输模型,分析了系统在固定频率和加性白色高斯噪声(AWGN,Additive White Gaussian Noise)信道条件下的链路性能.利用计算机进行蒙特卡罗仿真,结果表明:在AWGN信道和瑞利衰落信道下,LDPC编码方案可以有效地降低数据链系统的误比特率,取得比采用里德.所罗门编码的联合战术信息分发系统更好的误码性能.LDPC码作为信道编码技术的备选码组,为进一步提高战术数据链的可靠性提供了一种解决方案.
