改进交织的单层极化码高阶编码调制系统

极化码作为一种新型编码方式,被采纳为5G通信中的短码方案。本文将极化码应用到比特交织编码调制（Bit-Interleaved Coded Modulation,BICM）系统,优化交织器的设计,提出了一种新型交织算法。相比于现有的交织算法,新型交织算法的提出是基于比特信道可靠性衡量参数,将高可靠性的比特信道与低可靠性的比特信道交错设计,按照高可靠性信道对低可靠性信道辅助译码的方式,提高极化码的纠错性能。由于新型交织算法只存在于比特信道可靠度参数的简单排序,在复杂度上没有明显增加。仿真结果表明:新型交织算法具有优异的性能,当误码率为10-5,码长为256时,采用新型交织算法的极化码BICM系统与LDPC码的BICM系统相比大约有1.51 dB的增益。      

一种极化码MLC编码优化方案

为了降低极化码(Polar Codes)多层编码(Multilevel Coding)的实现复杂度,提出了一种改进的MLC编码实现算法。改进的算法中利用固定比特矩阵自包含特点,设计了一种使用单一编码器实现不同码率多层编码的方案,克服了算法中需要使用多个编码器的缺点,降低了系统复杂度和资源使用率。同时利用编码矩阵中BN可通过比特翻转实现的特点,提高了编码速度。理论推导和仿真结果表明改进的实现算法编译码性能与MLC算法性能一致,资源消耗更低。     

极化码原理及应用

基于信道的组合和分离,当组合信道的数量趋于无穷大的时候,一部分信道趋向于完美的信道,而一部分信道则趋向于纯噪声信道,即信道极化现象。基于此信道极化现象可以构造一种极化码,选择性使用组合信道中比较好的,因此极化码理论上可以达到香农限。极化码的原理包括极化码基础、极化码结构、极化码编码、SC译码。最后给出了在源编码的领域里应用极化码的一种方法,较小的牺牲码率而带来性能上较大的提高。     

基于重复累积码的BICM系统译码算法

重复累积码(RA)由于其编译码复杂度低、性能接近香农限的优点,目前得到学术界的广泛关注。文中研究了RA码及其译码算法,并将其应用于比特交织编码调制(BICM)系统。针对低信噪比下基于RA码的编码调制系统误码率较高的问题,提出了一种改进算法,该算法通过在解调器和译码器之间引入迭代处理,利用译码器输出的外信息改善解映射结果,从而降低了系统误码率。仿真结果表明,在加性高斯白噪声(AWGN)信道、瑞利(Rayleigh)衰落信道下,BICM系统使用迭代的译码算法与原算法相比,误码性能有较明显提高。     

LTE系统中Turbo编译码仿真与性能分析

介绍了LTE Turbo编译码方法,基于硬件实现对编码和交织器的计算进行了简化,提高了编码效率,利用Matlab仿真分析性能,分别采用Log-MAP算法和Max-Log-MAP算法进行译码,实现时结合项目需求综合考虑采用了误码率性能较好的Log-MAP算法。     

比特交织IRA码编码调制

提出了不规则重复累积（IRA）码实现比特交织编码调制（BIRACM）的设计方案,并在AWGN和Rayleigh平衰落信道下进行了仿真。仿真结果表明：BIRACM的性能优于传统的网格编码调制和比特交织编码调制。     

极化码编码器的硬件实现

基于信道的组合和分离,当组合信道的数量趋向于无穷大的时候,一部分信道趋向于完美的信道,而一部分信道则趋向于纯噪声信道,即信道极化现象。基于信道极化现象,可以构造极化码,通过选择性使用比较好的组合信道,其纠错能力理论上可以达到香农限。提出了一种简单的基于部分并行输入的极化码编码器的硬件结构,并进行了设计与实现。     

极化码在中继编码协作系统中的性能研究

极化码作为近年热门的编码方法,越来越受到人们的重视。对极化码的基本原理与编译码方法进行了简要介绍,分析了极化码的Plotkin结构的构造过程。在介绍传统中继协作通信系统和编码协作技术的基础上,提出基于Plotkin结构的极化码中继编码协作方案,具体分析了协作方案的实现过程,通过具体的理论分析和仿真结果说明,与非协作方式相比,在不同的中继信道条件下,该方案有不同程度的性能提升,同时,得出在中继节点不同的信息选取方式也可以带来不同的性能提升的结论。     

RS码在空空导弹遥测系统中的应用

为了增强空空导弹遥测系统抗误码能力,使遥测数据传输更为可靠,需要在遥测系统弹栽部分采用纠错编码技术。根据空空导弹遥测系统的特点采用RS码作为遥测系统纠错编码,分析了RS码的编码原理及实现方法,探讨了数据交织与解交织的原理,介绍了遥测系统中RS码的应用方法。实验证明,在设计能力范围内,Rs码可正确恢复遥测数据传输过程中产生的误码,完全满足设计需求。     

Performance comparison of systematic polar code and non-systematic polar code

Polar code in channel coding schemes is a research hotspot in 5G communication field.Polar code is susceptible to error propagation under successive cancellation decoding,and the performance of the code at short and medium block lengths is not ideal.For the problems,the performance difference between systematic polar code and non-systematic polar code was studied under various simulation conditions.Simulation results demonstrate that systematic polar code has advantage over non-systematic polar code in bit error rate performance,and the former are more robust against error propagation than the latter under successive cancellation decoding.The above results are considerable importance from the theoretical values in 5G communication and performance optimization of polar code.     

Optimizing low complexity encoding method for systematic polar code

In order to solve the delay caused by step-by-step calculation and the computational complexity caused by iterative “exclusive-or” computation during the encoding process,a dimensionality reduction strategy was proposed and defined.Based on this,system polarization code parallel coding algorithm for cracking strategy was proposed.Simulation and computational complexity analysis were carried out on AWGN channel.The results show that the coding gain of the above algorithm is slightly better than the traditional one or almost the same,but the computational complexity is up to 80.92%,which is more suitable for hardware implementation and engineering application.It is more suitable for hardware implementation and has a certain practical value.     

低复杂度、短时延的多级编码系统的实现

为了克服传统多级编码系统复杂度高、时延长的缺陷,本文研究了两种使多级编码更具实用性的解决方案。提出了一种将两级编码与8PSK结合的新型编码结构。与传统三级8PSK调制码相比,在保证同样传输率和误比特性能的情况下,使译码复杂度下降1／3甚至一半以上。     

基于极化码的无线光通信副载波误码性能分析

提出了一种基于极化码的无线光信道副载波调制方法,给出了极化编译码的具体算法过程,并将其应用于无线光通信系统。在不同大气湍流强度下,对系统的差错性能进行了仿真分析,其重对基于极化码的二相相移键控和四相相移键控两种调制方法的误码率进行了对比,结果表明,采用极化码的副载波二相相移键控调制系统的性能优于四相相移键控系统。最后,实验比较分析了极化编码前后副载波调制系统的误比特率,结果表明,在无线光通信大气湍流信道模型下,采用副载波极化码编码调制技术可使误码率性能改善一个量级。     

Coded overlapped code division multiplexing system with Turbo product structure

Coded overlapped code division multiplexing system with Turbo product structure (TPC-OVCDM) is introduced, and trellis coded modulation (TCM) code is employed as error correcting code for uncoded overlapped code division multiplexing (OVCDM) system. In such a scheme, row code and column code are TCM and OVCDM spreading code, respectively. Data bits are only encoded directly by TCM and transformed into a matrix. Each column of this matrix is then permuted by symbol interleaver before being encoded by OVCDM spreading code. During iterative decoding process in the receiver, two constituent decoders use symbol by symbol BCJR algorithm in the log domain. The order of decoding two sub-codes is determined by the encoding order. The proportion of TCM coding and OVCDM coding affects system performance. For fixed coding structure and symbol interleaver, the performance of TPC-OVCDM systems of different proportions of additive white Gaussian noise (AWGN) channel have been simulated. The results show that TPC-OVCDM system of reasonable proportion can achieve significant coding gain, compared with uncoded OVCDM system under the condition of same spectral efficiency at bit error rate (BER) level of 10-5 .     

LTE系统中多用户MIMO容量分析

首先简单介绍了LTE通信技术,在此基础上分析单用户MIMO系统容量以及相应的功率分配问题,随后对多用户MIMO系统功率分配问题做了简单介绍,并给出上行链路和下行链路的容量区域表达式,最后给出4种信道情况下容量之间的关系。     

LTE系统中资源调度机制的研究与实现

本文对LTE系统中资源调度机制进行深入研究,提出了一种实用的调度机制实现方法。首先阐述了资源调度机制的实现方法,然后详述与资源调度相关的两个过程的控制流程：BSR、SR,描述了BSR过程的触发机制,针对BSR与SR的协同流程给出了其实现流程图,并根据最后实现的代码对调度流程进行TTCN协仿真测试,得出MSC图与调度流程图进行校验。最后总结了LTE系统中资源调度的优势及本文提出的资源调度实现方法,从而为LTE系统中资源调度机制的实现提供参考。     

Chaotic sequence based polar code encrypted scheme in negative secrecy capacity case

A chaos based encrypted polar coding scheme,which could be applied to the negative secrecy capacity case,was proposed.Chaotic sequences were employed to encrypt the information bits and fill the frozen bits.And multi-block polar coding structure was also employed in the proposed scheme.The proposed scheme was featured as lower complexity and higher secrecy transmission rate.Corresponding mathematical analysis had been performed in terms of the error probability,security and transmission rate.The result reveals that the proposed scheme can achieve reliability,security in negative secrecy capacity case.What’s more,it has relatively low complexity and high secrecy transmission rate compared with the existing schemes.