确定性交织器的研究

本文分析了交织器在turbo码中的重要作用，以及随机交织器存在的缺陷，并提出了一种确定性交织器的设计方法。该交纪念品器具有简明的解析表达式，易于实现。计算机仿真结果表明，该确定交织器可以获得的性能优于随机交织器的平均性能。     

数字电视传输中的关键技术

纠错编码在实际应用中往往要结合数据交织技术。因为许多信道差错是突发的，即发生错误时，往往是有很强的相关性，甚至是连续一片数据都出了错。这时由于错误集中在一起，常常超出了纠错码的纠错能力。所以在发送端加上数据交织器，在接收端加上解交织器，使得信道的突发差错分散开来，把突发差错信道变成独立随机差错信道，这样可以充分发挥纠错编码的作用。交织器就是使数据顺序随机化，分为周期交织和伪随机交织两种。     

短帧Turbo码交织器的设计

本文给出一种分组交织器与最佳周期交织器相结合对数据进行交织的方案，可应用在短帧Turbo码交织器的设计中。通过对这种交织器的性能进行计算机模拟，本文得出在短帧Turbo码中该交织器的性能优于伪随机交织器和一般的分组交织器的性能。     

交织器的研究和在Turbo码中的应用

交织器不但在传输性能较差的无线信道中，提高了抗突发错误的能力，而且在Turbo码的设计中起到了重要作用。本文分析了几种交织器的基本原理并对其性能进行了比较，提出了今后交织器研究的重点。     

一种改进的S-random随机交织器的设计

本文对Turbo码中的关键部件——交织器作了分析，阐明了交织器在Turbo码中的重要作用。同时，混沌理论是非线性科学中的研究热点，对现代科学产生了广泛而深远的影响。本文基于Henon混沌模型和S-random交织器的设计思想提出了一种改进的交织器设计方法，并将其应用于Turbo码中。通过Turbo码的距离谱和联合界对比，本文设计的S-henon交织器在改善Turbo性能上优于S-random交织器。     

纠错编码系统交织器的设计

介绍了纠错编码系统中交织器的作用,以及交织器的几种类型的特性和实现方法,着重讨论了具有高度应变能力的伪随机交织器,最后对各种交织方法在不同干扰下的性能作了分析与对比,得出了一些基本结论。     

矩阵交织器的通用CPLD实现方法

交织编码在3G系统中已经大量使用，数据通过卷积编码后进行分组交织，在接收端完成反交织，将连续误码分散成非连续误码，从而使得误码在纠错允许的范围内得到纠正；CPLD(复杂可编程逻辑器件)具有方便的在线编程功能，可以用来实现交织编码；考虑到矩阵交织器的多样性而设计的通用矩阵交织器，只须通过修改一些参数值即可实现不同的交织器，大大节省了设计时间。     

Turbo码中快速交织器的设计

分析了交织器在Ｔｕｒｂｏ码中的重要作用，以及目前交织器存在的缺陷，介绍了一种快速交织器的设计方法。该交织器易于实现，具有交织时延低的突出优点。计算机仿真结果表明，该快速交织器可以获得优异的性能。     

一种交织器和解交织器的FPGA电路实现

交织和解交织是组合信道纠错系统的一个重要环节,交织器和解交织器的实现方法有多种。本文利用Altera公司开发的Quartus软件平台和仿真环境,设计一种交织器和解交织器FPGA电路单倍实现的方法,并分析该电路实现的特点。 外交织的基本原理 实际信道中产生的错误往往是突发错误或突发错误与随机错误并存,如果首先把突发错误离散成随机错误,然后再去纠随机错误,那么系统的抗干扰性能就会进一步得到提高。交织器的作用就是将比较长的突发错误或多个突发错误离散成随机错误,即把错误离散化。交织器按交织方式可分为交织深度固定的交织器(如分组交织器和卷积交织器)和交织深度不断变化的随机交织器;按交织对象可分为码元交织器和码段交织     

Turbo编码中的交织技术

Turbo码是近年来提出的一种高性能的信道编码.Turbo码交织器的设计是Turbo编解码器设计中的关键.文中介绍了交织器的基本原理,详细地介绍了3种常见的交织器的交织原理.最后给出了交织器的设计准则.     

Design of cyclic shift interleavers for Turbo Codes

In this paper we consider cyclic shift interleavers for turbo coding. The properties of cyclic shift interleavers are discussed and compared with S-random interleavers. It is shown that the cyclic shift interleavers are equivalent or better than the S-random interleavers in the ability to break low weight input patterns. We estimated the performance of turbo codes with cyclic shift interleavers and compared it with the performance of S-random interleavers for varions interleaver sizes. The simulation results show that a turbo code with a cyclic shift interleaver can achieve a better performance than an S-random interleaver if the parameters of the cyclic shift interleaver are chosen properly. In addition, the cyclic interleavers have the advantages of lower design complexity and memory requirements.     

Performance of Möbius Interleavers for Turbo Codes

In this paper, we study the minimum free distance and error performance of turbo encoders with Möbius interleavers. In order to be capable of estimating the minimum free distance of these interleavers using binary-fixed point (BFP) algorithm, new deterministic interleavers called “truncated Möbius interleavers” are defined and constructed. It is shown how the shifted cycles of these interleavers can be related to the cycle structure of the primary Möbius transformation and its coefficients. By adjusting some parameters, an upper bound on the number of total tested BFPs for the proposed truncated Möbius interleavers is found. One distinctive property of Möbius interleavers is that their inverse can also be represented and computed with Möbius functions. Simulations are conducted to compare the error performance of the proposed truncated Möbius interleavers with quadratic permutation polynomial (QPP) interleavers whose inverses are also representable by a quadratic equation (Ryu and Takeshita in IEEE Trans Inf Theory 52(3):1254–1260, 2006). It is finally shown that the truncated Möbius interleavers can interleave sequences of information bits faster than QPP interleavers.     

分布式视频编码中符号Turbo码交织器的设计

分析了交织器在Turbo码中的作用,指出了现有的几种交织器的缺点.设计了两种新型的基于块交织的S随机交织器和基于伪随机交织的S随机交织器.仿真结果表明,与现有的几种交织器相比,这两种交织器在Turbo码译码迭代次数及延时方面性能更好,更适合于分布式视频编码系统.     

Improved method for searching interleavers from a certain set using Garello’s method with applications for the LTE standard

In this paper, we propose a method for searching interleavers within a certain class, with the aim of designing turbo codes with good distance spectrum. The method is based on a modified version of Garello’s algorithm and consists in the calculation of frame error rate truncated upper bound. Here, it is applied to quadratic permutation polynomial (QPP) interleavers able to outperform those chosen for the long-term evolution (LTE) standard, for lengths up to 1,504 bits. Three classes of interleavers have been analyzed: (1) the set of QPP interleavers with the largest spread, (2) the set of QPP interleavers with a spread parameter equal to that of LTE interleaver and the highest refined nonlinearity degree, and (3) the complete set of all QPP interleavers for lengths up to 1,008. The distance spectrum optimization is made for all classes. Compared to previous methods for finding QPP-based interleavers, the search complexity is reduced, with improved performances in terms of search time, allowing interleavers of higher length. For lengths up to approximately 450, the best interleavers were found in the first class. For longer lengths, the second class contained the best ones.     

2-Dimension Interleaver Design for IDMA Systems

A new design method interleavers, 2-dimension interleavers, are proposed for interleave division multiple access （IDMA） systems. With a same interleaving rule named I＇, the row indices and column indices of a traditional block interleaving matrix are scrambled to obtain an interleaver, which is marked as the master interleaver. F is produced by a loworder PN sequence generator. Two ways are provided for generating different interleavers. One is that all interleavers are generated by the circular shifting master interleaver. The other is that different inter leavers are generated by different Ts. Besides, we prove that the minimum distance between two adjacent bits resulted from 2-dimension interleaves is much larger than that of other schemes, such as random interleavers, power interleavers, and shiffting interleaves. The simulation results show that 2-dimension interleavers can achieve much better performance with much less resource consumption than random interleavers in IDMA systems.     

信道交错器的实现方案及其优缺点

系统地介绍信道交错器(Interleaver)技术的发展状况,包括最基本的Interleaver类型和最新发展起来的一些技术,同时对比了各种Interleaver技术的优缺点,指出Interleaver技术还存在的问题,并描述Interleaver技术的应用前景。     

Stream-oriented turbo codes

This work considers the design and performance of a stream-oriented approach to turbo codes which avoids the need for data framing. The stream paradigm applies to both serial and parallel turbo codes using continuous, free-running constituent encoders along with continuous, periodic interleavers. A stream-oriented turbo code based on parallel concatenated convolutional codes (PCCC) is considered and interleaver design criteria are developed for both block and nonblock periodic interleavers. Specifically, several nonblock interleavers, including convolutional interleavers, are considered. Interleaver design rules are verified using simulations where it is shown that nonblock interleavers with small-to-moderate delay and small synchronization ambiguity can outperform block interleavers of comparable delay. For large-delay designs, nonblock interleavers are found which perform within 0.8 dB of the capacity limit with a synchronization ambiguity of N=11     

Interleavers for turbo codes using permutation polynomials over integer rings

A class of deterministic interleavers for turbo codes (TCs) based on permutation polynomials over /spl Zopf//sub N/ is introduced. The main characteristic of this class of interleavers is that they can be algebraically designed to fit a given component code. Moreover, since the interleaver can be generated by a few simple computations, storage of the interleaver tables can be avoided. By using the permutation polynomial-based interleavers, the design of the interleavers reduces to the selection of the coefficients of the polynomials. It is observed that the performance of the TCs using these permutation polynomial-based interleavers is usually dominated by a subset of input weight 2m error events. The minimum distance and its multiplicity (or the first few spectrum lines) of this subset are used as design criterion to select good permutation polynomials. A simple method to enumerate these error events for small m is presented. Searches for good interleavers are performed. The decoding performance of these interleavers is close to S-random interleavers for long frame sizes. For short frame sizes, the new interleavers outperform S-random interleavers.     

Modified Collision-Free Interleavers for High Speed Turbo Decoding

Inter-window shuffle (IWS) interleavers are a class of collision-free (CF) interleavers that have been applied to parallel turbo decoding. In this paper, we present modified IWS (M-IWS) interleavers that can further increase turbo decoding throughput only at the expense of slight performance degradation. By deriving the number of M-IWS interleavers, we demonstrate that the number is much smaller than that of IWS interleavers, whereas they both have a very simple algebraic representation. Further, it is shown by analysis that under given conditions, storage requirements of M-IWS interleavers can be reduced to only 368 storage bits for variable interleaving lengths. In order to realize parallel outputs of the on-line interleaving addresses, a low-complexity architecture design of M-IWS interleavers for parallel turbo decoding is proposed, which also supports variable interleaving lengths. Therefore, the M-IWS interleavers are very suitable for the turbo decoder in next generation communication systems with the high data rate and low latency requirements.