共查询到20条相似文献,搜索用时 46 毫秒
1.
2.
3.
4.
环E+uF2是介于环Z4与域F4之间的一种四元素环,因此分享了环Z4与域F4的一些好的性质,此环上的编码理论研究成为一个新的热点。该文给出了环E+uF2的Galois扩张的相关理论,指出此Galois扩环的自同构群不同于Z4环上的Galois扩环的自同构群;定义了Galois扩环上的迹码的概念及子环子码的概念,证明了此Galois扩环上的一个码的对偶码的迹码是该环的子环子码的对偶码。 相似文献
5.
MacWilliams恒等式是研究线性码及其对偶码的码字重量分布的一个非常有用的工具,而码字的重量分布的研究是编码研究中一个非常重要的研究方向.本文定义了环Z4+uZ4上长度为n的线性码的m-层李重量计数器,给出了环Z4+uZ4上长度为n的线性码关于李重量的一类MacWilliams恒等式.证明了该等式是生成矩阵在环Z4+uZ4上的环GR(4,m)+uGR(4,m)上线性码关于李重量的MacWilliams恒等式.进一步,利用Krawtchouk多项式,获得了环Z4+uZ4上长度为n的线性码的等价形式MacWilliams恒等式. 相似文献
6.
Maria Elena Valcher Ettore Fornasini 《Multidimensional Systems and Signal Processing》1994,5(3):231-243
Two-dimensional (2D) finite codes are defined as families of compact support sequences indexed in Z × Z and taking values in F
n
, F a Galois field. Several properties of encoders, decoders and syndrome decoders are discussed under different hypotheses on the code structure, and related to the injectivity and primeness of the corresponding polynomial matrices in two variables. Dual codes are finally introduced as families of parity checks on a given modular code, and related to the standard theory of 2D behaviors. 相似文献
7.
8.
In this paper, we investigate and compare the asymptotic performance of concatenated convolutional coding schemes over GF(4) over additive white Gaussian noise (AWGN) channels. Both parallel concatenated codes (PCC) and serial concatenated codes (SCC) are considered. We construct such codes using optimal non‐binary convolutional codes where optimality is in the sense of achieving the largest minimum distance for a fixed number of encoder states. Code rates of the form k0/(k0 + 1) for k0=1, 8, and 64 are considered, which suite a wide spectrum of communications applications. For all of these code rates, we find the minimum distance and the corresponding multiplicity for both concatenated code systems. This is accomplished by feeding the encoder with all possible weight‐two and weight‐three input information patterns and monitoring, at the output of the encoder, the weight of the corresponding codewords and their multiplicity. Our analytical results indicate that the SCC codes considerably outperform their counterpart PCC codes at a much lower complexity. Inspired by the superiority of SCC codes, we also discuss a mathematical approach for analysing such codes, leading to a more comprehensive analysis and allowing for further improvement in performance by giving insights on designing a proper interleaver that is capable of eliminating the dominant error patterns. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
9.
10.
环F2+uF2上长为2e的循环码 总被引:5,自引:0,他引:5
近十多年来,有限环上的循环码一直是编码研究者所关心的热点问题,本文证明了R[x]/<xn-1>不是主理想环,其中R=F2 uF2,u2=0且n=2e.分3种情形讨论了环R[x]/<xn-1>中的非零理想,并给出了R上循环码的可以唯一确定的生成元的表达形式,同时给出了R上循环码的李距离的一个上界估计. 相似文献
11.
12.
环F2+uF2是介于环Z4与域F4之间的一种四元素环,因此分享了环Z4与域F4 的一些好的性质,此环上的编码理论研究成为一个新的热点。该文给出了环F2+uF2 的Galois扩张的相关理论,指出此Galois扩环的自同构群不同于Z4环上的Galois扩环的自同构群;定义了Galois扩环上的迹码的概念及子环子码的概念,证明了此Galois扩环上的一个码的对偶码的迹码是该环的子环子码的对偶码。 相似文献
13.
The self-orthogonal condition is analyzed with respect to symplectic inner product for the binary code that generated by [B1 I B2 B3], where B, are the binary n x n matrices, I is an identity matrix. By the use of the binary codes that generated by [B1 I B2 B2 BT1], asymptotic good [[2n, n]] additive quantum codes are obtained. 相似文献
14.
15.
Analysis and performance evaluation of new coding options for space telecommand links ‐ Part I: AWGN channels
下载免费PDF全文
![点击此处可从《International Journal of Satellite Communications and Networking》网站下载免费的PDF全文](/ch/ext_images/free.gif)
M. Baldi F. Chiaraluce R. Garello N. Maturo I. Aguilar Sanchez S. Cioni 《International Journal of Satellite Communications and Networking》2015,33(6):509-525
We investigate and compare, over the additive white Gaussian noise channel, different options for updating the error correcting code currently used in space mission telecommand links. Besides some more consolidated proposals, using low‐density parity‐check codes, we characterize and assess the performance of alternative schemes, based on parallel turbo codes and soft‐decision decoded Bose‐Chaudhuri‐Hocquenghem (BCH) codes. The analysis considers relevant metrics like the codeword error rate, the frame error rate, and the undetected frame error rate. The considered codes include binary and non‐binary low‐density parity‐check codes, parallel turbo codes and extended BCH codes, with different decoding algorithms. The complexity of the various schemes and possible limits for their application are considered and discussed. Several numerical examples are provided. International Journal of Satellite Communications and Networking. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
16.
17.
1 IntroductionRecently,anewspace timecodeadaptedtomultipleantennaswirelessfadingchannelhasbeenproposed[1~6] .Thecodesarethejointdesignofcoding ,modulation ,transmissionandreceptiondi versityto providethebesttradeoffbetweendatarates,diversityadvantageandcodes… 相似文献
18.
19.
DVB-S2中LDPC码生成法解析 总被引:1,自引:0,他引:1
文章在详细分析DVB-S2标准的基础上,研究了DVB-S2中LDPC码的码字构造法则,推导出校验矩阵结构并进行分析,得出DVB-S2中LDPC码的相关参数。同时对标准中的一类码在AWGN信道中进行了仿真,仿真结果表明,这类码性能优异,具有很强的纠错能力。 相似文献
20.
Mohammed Usman 《International Journal of Electronics》2013,100(8):1037-1050
Mobile broadband has opened the possibility of a rich variety of services to end users. Broadcast/multicast of multimedia data is one such service which can be used to deliver multimedia to multiple users economically. However, the radio channel poses serious challenges due to its time‐varying properties, resulting in each user experiencing different channel characteristics, independent of other users. Conventional methods of achieving reliability in communication, such as automatic repeat request and forward error correction do not scale well in a broadcast/multicast scenario over radio channels. Fountain codes, being rateless and information additive, overcome these problems. Although the design of fountain codes makes it possible to generate an infinite sequence of encoded symbols, the erroneous nature of radio channels mandates the need for protecting the fountain‐encoded symbols, so that the transmission is feasible. In this article, the performance of fountain codes in combination with convolutional codes, when used over radio channels, is presented. An investigation of various parameters, such as goodput, delay and buffer size requirements, pertaining to the performance of fountain codes in a multimedia broadcast/multicast environment is presented. Finally, a strategy for the use of ‘convolutional fountain’ over radio channels is also presented. 相似文献