一种改进的极化码置信译码器

在极化码置信（ BP）译码的因子图中,当承载确定信息的节点的对数似然信息计算错误时,可以被检测到。此时,对于因子图中参与该似然信息计算的节点,引入一个修正参数,以修正该节点承载的信息的对数似然信息。修正参数可以由密度进化的高斯近似算法得到。给出了置信译码原理及相应的改进算法,最后给出了复杂度分析和性能仿真。数据结果表明,在牺牲很小的复杂度的条件下,相比原算法,修正算法能够获得0.2 dB左右的比特信噪比增益。     

莱斯信道中Polar码的构造及性能分析

Polar码是由Arikan提出的一种新的编码方式。它是基于信道极化理论,被证明在二进制离散无记忆信道下能够获得信道对称容量。本文给出了polar码在莱斯信道下的构造及性能分析,针对莱斯信道已知信道边信息（CSI）和未知信道边信息（NCSI）两种情况分别进行polar码的构造。仿真结果表明:相比于LDPC码,polar码的性能更加优良。此外,莱斯因子K越大,polar码的误比特率就越小。polar码在信道边信息已知的情况下性能比信道边信息未知时的好。因此Polar码在莱斯衰落信道中具有很好的性能,非常适合未来移动通信技术。      

一种改进的二阶Reed-Muller译码算法

研究了一种改进的RM译码算法—改进的Sidel,nikov-Pershakov算法(简称SP算法),详细叙述了原始算法的原理以及改进算法的译码步骤,并对两种算法进行了仿真实现,对它们的译码性能和算法复杂度进行了比较。改进的译码算法复杂度略优于原始算法,而改进后的算法的译码性能明显优于原始算法。     

极化码的编码构造

为了丰富极化码的编码构造理论,分析了极化码生成矩阵中与核矩阵密切相关的置换矩阵,论证置换矩阵所起的具体作用并给出了其具体形式,发现了置换矩阵内在的排列规律.介绍了系统极化码的两种编码方法,仿真结果表明系统极化码与非系统极化码具有相同的误帧率性能,但系统极化码的误比特率性能更好.     

基于系统极化码的协作通信系统性能研究

极化码作为一种新型的编码方式,具有理论上证明可以达到香农限、编译码复杂度低的优点。系统极化码比非系统极化码具有更优异的BER性能。将系统极化码与编码协作技术相结合,提出了一种基于系统极化码的协作通信方案,并对其进行了理论分析和性能仿真。仿真结果表明,提出的协作通信方案相比于非协作模式,有一定的性能提升。同时,与已有的Plotkin结构方案进行对比,所提出的协作方案具有更加优异的性能。     

一种基于Polar码的可抗差错图像传输方法

Polar码是第一种理论上被严格证明能达到香农限的信道编码方法。结合Polar码的构造特点,提出了一种基于Polar码的可抗差错的图像传输方法,将传输图像进行离散变换后获取的频率分量与Polar码极化后信道的可靠性一一对应,然后进行编码传输。仿真结果表明,新构造的图像传输系统,能以较少的信息完成图像传输,同时达到较高的传输质量,具有良好的可抗差错性和较高的传输效率。     

PAPR Reduction of OFDM Signals Using Partial Transmit Sequences and Reed-Muller Codes

This letter proposes a modified PTS technique using binary Reed-Muller (RM) codes for error correction and PAPR control in BPSK OFDM systems. A RM code is divided into the direct sum of a correcting subcode for encoding information bits and a scrambling subcode for encoding PAPR bits. The transmitted signal of the resulting OFDM sequence is selected with minimum PAPR from a number of candidates which are codewords of a coset of the scrambling subcode. We consider the RM codes in natural and cyclic orderings. Numerical results show that RM codes in cyclic ordering achieve better performance in PAPR reduction than RM codes in natural ordering.     

一种基于比特翻转的极化码FSCLF译码算法

针对串行抵消列表翻转(Successive Cancellation List Flip,SCLF)译码算法存在译码性能与复杂度不能同时兼顾的问题,提出了一种快速串行抵消列表翻转(Fast Successive Cancellation List Flip,FSCLF)译码算法.该算法通过加入四种特殊结点的识别来加快译码速率,同时构建了临界集(Critical Set,CS),不再依据先前译码错误而引起的错误传播,而是通过两种特殊结点即信息比特R1结点和单奇偶校验(Single-Parity-Check,SPC)结点分别对对数似然比(Log-Likelihood Ratio,LLR)值进行计算来判决并确定翻转位置,当奇偶校验位不满足时只需翻转与最不可靠输入LLR值相对应的信息比特,这样减少了翻转次数,从而降低了算法复杂度.仿真结果表明:在误块率为10-5时,所提出的FSCLF译码算法比原SCLF译码算法的信噪比改善了0.09 dB,为中短码长情况提供了参考算法.     

基于CNN扰动的极化码译码算法

针对中短码长下串行抵消(SC)算法性能较差,且串行抵消列表(SCL)算法复杂度较高等问题,根据译码纠错空间理论,该文提出了一种基于卷积神经网络(CNN)扰动的极化码译码算法.对SC译码失败的接收序列,通过CNN产生相应的扰动噪声,并将该扰动噪声添加到接收信号中,然后根据重新计算的似然信息进行译码.仿真结果表明:与SC译码算法相比,所提出的算法约有0.6 dB的增益,与SCL(L=16)译码算法相比,该算法约有0.1 dB的提升,且平均复杂度更低.     

Hardware Implementation of Successive-Cancellation Decoders for Polar Codes

The recently-discovered polar codes are seen as a major breakthrough in coding theory; they provably achieve the theoretical capacity of discrete memoryless channels using the low-complexity successive cancellation decoding algorithm. Motivated by recent developments in polar coding theory, we propose a family of efficient hardware implementations for successive cancellation (SC) polar decoders. We show that such decoders can be implemented with O(N) processing elements and O(N) memory elements. Furthermore, we show that SC decoding can be implemented in the logarithmic domain, thereby eliminating costly multiplication and division operations, and reducing the complexity of each processing element greatly. We also present a detailed architecture for an SC decoder and provide logic synthesis results confirming the linear complexity growth of the decoder as the code length increases.     

空时码在频率选择性信道下的编码方案及性能比较

利用空时编码可以获得空间分集,空时码与OFDM结合可以使空时码应用于频率选择性信道。分析和比较了两种空时编码在频率选择性信道下OFDM相结合的编码方法。计算机仿真结果显示了不同信道条件下两种编码方法的性能差异。     

一种基于新度量准则的极化码SCLF译码算法

为了解决串行抵消(Successive Cancellation,SC)译码算法在中短码长情况下译码性能不佳的问题,在SC译码算法的基础上增加路径列表和比特翻转方法得到一种改进的串行抵消列表翻转(Successive Cancellation List Flip,SCLF)译码算法.该算法利用比特翻转构建最不可靠的信息位集合,称为翻转集合(Flipping Set,FS),同时提出一种新的度量法则来缩小FS的范围、提高FS的准确率.仿真结果表明,随着信噪比的增大,所提出的SCLF译码算法误块率(Block Error Rate,BLER)有较大提升,当BLER为10-3时,SCLF(码长N=256,列表大小L=8)译码算法的增益比SC(N=256)译码算法提升了 0.55 dB;当BLER为10-4时,SCLF(N=256,L=8)译码算法的增益比CA-SCL(N=256,L=8)译码算法提升了 0.22 dB;当BLER为10-5时,SCLF(N=256,L=16)译码算法的增益比CA-SCL(N=256,L=16)译码算法提升了 0.17 dB.     

Performance of Reed-Muller codes and a maximum-likelihood decodingalgorithm for OFDM

The performance of Reed-Muller encoding and a maximum-likelihood decoding algorithm for orthogonal frequency-division multiplexing is presented. The example codes have a tightly bounded peak-to-mean envelope power ratio, while simultaneously enabling powerful error correction. We present a maximum-likelihood decoder that makes use of a distance-preserving map and multiple fast Hadamard transforms. Its operation is described in detail and its performance is assessed under realistic channel conditions     

Comparison of Four High Performance Dual Polar Antennas for Base Stations

Wireless Personal Communications - In this paper four types of cross-dipoles antennas, highly compatible to be utilized in base stations of cellular systems, were thoroughly compared: (1) dipoles...     

基于XOR纠删码的性能分析

基于异或的纠删码有一个不规则结构,这个结构可能允许它以汉明码码距或者超过汉明码码距的码距容错。为了能够完全描述基于异或纠删码的容错情况,本文提出一种基于异或纠删码的容错机制：最小删除列表。相对于其他基于异或纠删码的容错机制,最小纠删列表是一种有效机制。在本文我们还给出了一种有效确定纠删码的最小删除列表的算法。这个算法使用纠删码的结构去有效确定最小删除列表。试验结果表明,对于给定的纠删码,有超过最小删除列表数目的100倍的删除数目。     

降低SCL译码错误的级联极化码

串行抵消列表(SCL)算法是极化码的一种近似最大似然(ML)译码算法,基于该算法的循环冗余校验(CRC)级联极化码、校验(PCC)级联极化码纠错性能优良,已成为5G极化码标准编码方案。总结了SCL译码错误类型,并从降低SCL译码错误的角度揭示了CRC级联极化码、PCC级联极化码,以及CRC辅助的PCC级联极化码,三者提升SCL译码性能的原理。仿真结果表明:CRC辅助的校验级联极化码可以显著降低SCL译码错误,并在较高信噪比(SNR)范围内,呈现出最佳的纠错性能。     

Belief Propagation Decoding of Polar Codes Using Intelligent Post-Processing

Polar code is a channel coding method that has been proved to be able to reach Shannon capacity in the binary discrete memoryless channel. Because of the superior performance and low encoding and decoding complexity, polar code has attracted extensive attention in the industry and been chosen as the channel coding scheme for the control channel in the scenario of EMBB in 5G mobile communication. In this work, we propose an intelligent BP decoding algorithm of polar code based on smart post-processing. We employ the neural network to classify the output data of regular BP decoding into “good-bit” and “bad-bit” categories. We also design a strategy to search the bits, which are most probably incorrect from the “bad-bit” group for post-processing. Then, we can invert the “bad-bit” to correct the residual error in the Belief Propagation (BP) iterative process. Simulation results prove that the proposed algorithm can achieve at least 0.5dB error correction performance enhancement compared with the regular BP decoding with slight computation complexity and energy consumption increase.

     

RS-RNS级联码及其性能

本文通过级联码方法,构造了一类适应于对抗信道记忆的差错控制码RS-RNS级联码。级联码的外码为多进制符号Reed-Solomon码,内码为剩余数系统生成码。并且分析了RS-RNS级联码的性能。     

An Efficient Software List Sphere Decoder for Polar Codes

Journal of Signal Processing Systems - Polar codes, first achieving the capacity of symmetric binary-input discrete memoryless channels (B-DMCs), have been standardized for eMBB control channels....     

RS—RNS级联码及其性能

本文通过级联码方法,构造了一类适应于对抗信道记忆的差错控制码;ＲＳ－ＲＮＳ级联码。级联码的外码为多进制符号Ｒｅｅｄ－Ｓｏｌｏｍｏｎ码,内码为剩余数系统生成码,并且分析了ＲＳ－ＲＮＳ级联码的性能。