Interleaver实现方案中的几个问题

当前光通讯信道密度的迅速增加和数据传输速率的不断提高对DWDM系统的性能提出了空前严格的要求。而Interleaver就是50GHz的DWDM系统中所必须采用的一种全新器件,本文介绍了Interleaver的温度稳定性、带宽以及色散问题的几种解决方法。     

用于DWDM系统的双折射型Interleaver原理分析

介绍了交叉复用器 (Interleaver)在密集波分复用 (DWDM)光纤通信系统中的作用 ,利用各向异性晶体的双折射和偏振光的干涉分析了双折射型Interleaver器件的原理 ,给出了一种双折射型Interleaver与薄膜滤波器混合结构的DWDM光纤通信系统的概念设计     

光波分复用器件和光学梳状滤波器理论及最新进展

介绍了波分复用（WDM）/解复用器件和光学梳状滤波器（Interleaver)的几种实现方法，分析了各种方法的特点和现状，并提出了实现更密集WDM的一种新途径——DWDM器件和Interleaver级联方案。     

Interleaver技术

Interleaver技术的出现更新了密集波分复用中分波／合波器件设计的理念,大大降低密集波分复用器的设计压力。本文较系统地介绍了Interleaver的理论及应用,并对50GHz Interleaver目前的技术状况和实现方法作了较为全面的阐述和比较。     

Interleaver实现方案中的几个问题

当前光通讯信道密度的迅速增加和数据传输速率的不断提高对DWDM系统的性能提出了空前严格的要求。而Interleaver就是50GHz的DWDM系统中所必须采用的一种全新器件，本文介绍了Interleaver的温度稳定性、带宽以及色散问题的几种解决方法。     

DWDM系统中的Interleaver技术

目前密集波分复用(DWDM)系统已广泛应用于长途干线、城域网．并扩展至接入网。其中波分复用／解复用器是系统的核心器件之一．而50GHz的密集波分复用更要靠一种交叉波分复用(Interleaver)的全新器件．为此详细阐述了Interleaver的原理、主要实现方案及其特点。     

一种基于双通MZI型Interleaver的研究

提出了一种基于双通Mach-Zehnder(M-Z)干涉仪型波长交错复用技术(Interleaver),并对这种器件的原理和相关性能进行了理论分析和实验研究.结果表明,新结构Interleaver的光谱与常规的M-Z干涉仪型Interleaver相比,其消光比得到了很大提高.当信道间隔为 50 GHz时,消光比大于25 dB.研究结果对该型器件的研制有着重要的指导意义.     

光通信中的波分复用／解复用器技术

波分复用是实现大容量光通信的关键技术,实现DWDM的技术方法多种多样,论述了几种常用的技术原理,分析了各种技术的利弊,现有的每种技术都不是完全理想的。着重讨论了能利用现有波分复用器实现更窄通道间隔的光间插技术（Optical Interleaver),并提出用光纤F－P谐振腔制作Optical Interleaver。     

基于Michelson--三镜G-T腔型不等带宽Interleaver的研究

通过分析三镜G-T腔的非线性相位性质,提出用等间隔三镜G-T腔代替Michelson干涉仪的一个全反射镜,构成不等带宽Interleaver。该器件将50GHz信道间隔的输入信号分离成100GHz信道间隔的不等带宽奇偶两路输出信号,可分别用于40Gb/s和10Gb/s传输,信道隔离度大于30dB。并经过计算机优化,得出所有满足DWDM系统以上要求的各反射镜的反射率。     

傅里叶顶端平坦型全光纤Interleaver的研究

分析了两级串联马赫 曾德尔(Mach Zehnder)干涉型奇偶交错滤波器(Interleaver)的透过率函数。理论上采用梯形波近似的方法,利用傅里叶级数展开的方法选取适当的参数,可得到输出波形通带平坦,阻带加宽的滤波器,其输出稳定性和隔离度均得到了提高。通过实验所得的结果与理论相吻合。     

MB-OFDM UWB系统中交织器盲识别方法

借助峰值平均功率比(PAR)与反转误码率(RSER)信息,实现MB-OFDM UWB系统在发送端选择最佳交织器后,在不传送交织辅助信息情况下,在接收端恢复发送端使用的交织器编号,实现交织过程盲识别。将反转误码率的检测应用到对交织器的盲识别中,改进MB-OFDM UWB系统中的交织器与解交织器部分,通过对反转误码率的比较识别出发送端所选择的交织器规格,进而达到对交织序列的盲识别。对常规与改进后的系统进行误比特率仿真比较后,发现改进后的MB-OFDM UWB系统具有较好的可靠性,可以通过反转误码率的比较信息得出交织器编号,进而得到交织序列,释放信道,达到真正意义上的交织盲识别,从而实现智能通信。     

Prunable Collision Free Random Interleaver Design

In this article we introduce a new collision free prunable random interleaver. The suggested interleaver is a joint structure involving rectangular and S-random interleaver. It comprises a general model for all kind of collision free prunable random interleavers. In addition, it can be designed for any number of parallel processors and any length of information sequence vector and can be considered also as a template for collision free prunable interleavers. The proposed interleaver can be used with all kind of turbo-like codes. The performance of the proposed interleaver is measured with parallel decodable serially concatenated convolutional codes (PDSCCCs) and compared to the PDSCCCs?? performance with collision full S-random interleaver.     

Interleaver design for turbo codes

The performance of a turbo code with short block length depends critically on the interleaver design. There are two major criteria in the design of an interleaver: the distance spectrum of the code and the correlation between the information input data and the soft output of each decoder corresponding to its parity bits. This paper describes a new interleaver design for turbo codes with short block length based on these two criteria. A deterministic interleaver suitable for turbo codes is also described. Simulation results compare the new interleaver design to different existing interleavers     

基于低码率线性分组码的分组交织长度识别

交织长度的识别是交织器识别过程中重要的步骤,关系到纠错码识别和信息的获取,具有重要的研究价值。文中简要介绍矩阵分析法,针对矩阵分析法容错能力不强的缺点,借助码重分布的概念,提出利用块重分布识别低码率二进制线性分组码序列交织长度的方法。最后,对两种方法进行仿真对比,分析了各自的适用范围和容错能力。     

低信噪比下随机交织器识别

针对Turbo码随机交织器参数识别问题,充分利用信道截获数据的软判决信息,提出了一种基于对数符合度的交织映射关系识别算法。该算法从计算总的编码方程成立概率出发,定义了能很好衡量概率大小的对数符合度概念,极大地简化了计算复杂度,使得计算量仅与截获码块数目和交织长度的平方有关,计算方式仅为大小比较与符号提取;再利用正确交织位置能够使总的编码方程成立的概率达到最大这一特性,依次实现各个位置的交织关系的识别。与现有算法相比,所提算法识别性能稍差,但计算复杂度更低。仿真结果表明,在信噪比为0 dB、交织长度为200时,仅需要截获码块数目为500,其正确识别率就能达到100%。     

Design and Analysis of Successive Decoding With Finite Levels for the Markov Channel

This paper proposes a practical successive decoding scheme with finite levels for the finite-state Markov channels (FSMCs) where there is no a priori state information at the transmitter or the receiver. The design employs either a random interleaver or a deterministic interleaver with an irregular pattern and an optional iterative estimation and decoding procedure within each level. The interleaver design criteria may be the achievable rate or the extrinsic information transfer (EXIT) chart, depending on the receiver type. For random interleavers, the optimization problem is solved efficiently using a pilot-utility function, while for deterministic interleavers, a good construction is given using empirical rules. Simulation results demonstrate that the new successive decoding scheme combined with irregular low-density parity-check (LDPC) codes can approach the identically and uniformly distributed (i.u.d.) input capacity on the Markov-fading channel using only a few levels.     

Turbo码交织器的等差错保护研究

Turbo码具有近Shannon限的突出纠错能力,是一种高性能的信道编码。文中分析了一般交织器的设计规则和进行Turbo码编码时存在的等差错保护问题。在此基础上,针对分组交织器提出了沿交织矩阵主对角线循环的信息写入机制,对于s 随机交织器增加了随机索引地址生成的约束条件,最终得到了两种具有等差错保护功能的Turbo码交织器。仿真结果表明,改进的交织器明显改善了Turbo码的误比特率性能。     

编织卷积码交织器的设计

编织卷积码(WovenConvolutionalCodes)是近年来所出现的一种新型高效纠错码,其中交织器的设计对分散突发错误、改善其纠错性能起着决定性的作用。传统的编织卷积码采用了行进列出的简单的交织方式,本文针对编织卷积码的结构特性设计了两种不同的交织器并通过系统仿真比较了它们的性能,仿真结果显示行式交织器极大地改善了系统性能,是目前为止最优的编织卷积码的交织器。     

Design of parallel concatenated convolutional codes

A parallel concatenated convolutional coding scheme consists of two constituent systematic: convolutional encoders linked by an interleaver. The information bits at the input of the first encoder are scrambled by the interleaver before entering the second encoder. The codewords of the parallel concatenated code consist of the information bits followed by the parity check bits of both encoders. Parallel concatenated codes (turbo codes), decoded through an iterative decoding algorithm of relatively low complexity, have been shown to yield remarkable coding gains close to theoretical limits. We characterize the separate contributions that the interleaver length and constituent codes give to the overall performance of the parallel concatenated code, and present some guidelines for the optimal design of the constituent convolutional codes     

A cost-function based technique for design of good prunable interleavers for turbo codes

This paper addresses the design of semi-random, prunable interleavers for parallel concatenated convolutional codes (PCCC). The proposed technique is iterative and is based on the growth of a smaller interleaver up to the desired length N. The optimization is achieved via a minimization using a cost-function strictly related to both the correlation properties of the extrinsic information and the concept of spread of an interleaver. Performance of the designed interleavers are given in terms of bit error rate (BER) and frame error rate (FER). Comparisons are given with respect to other prunable and ad-hoc interleaver design techniques already proposed in literature. The designed interleavers are prunable and have a behavior very similar to the interleavers designed with techniques which maximize the spread of the permutation.