Improved Performance of Maximum Likelihood Decoding Algorithm with Efficient Use of Algebraic Decoder

A new soft decision maximum-likelihood decoding algorithm, which generates the minimum set of candidate codewords by efficiently applying the algebraic decoder is proposed. As a result, the decoding complexity is reduced without degradation of performance. The new algorithm is tested and verified by simulation results.Panagiotis G. Babalis was born in Athens, Greece, on January 3, 1974. He received his Diploma of electrical and computer engineering and the Ph.D. degree, both from National Technical University of Athens (NTUA), Athens, Greece, in 1996 and 2001, respectively. His main research interests include mobile satellite communications, modulation, and wireless communications systems coding. Dr. Babalis is a member of the technical Chamber of Greece.Panagiotis T. Trakadas was born in Athens, Greece, on January 14, 1972. He received his Diploma of Electrical and Computer Engineering and the Ph.D. degree from National Technical University of Athens (NTUA), Athens, Greece, in 1996, and 2001, respectively. From 1998 to 2001, he participated in many European projects as a researcher. His main research interests include mobile communications systems and electromagnetic compatibility topics. Dr. Trakadas is a member of the Technical Chamber of Greece and IEEE Society.Theodore B. Zahariadis received his Ph.D. degree in electrical and computer engineering from the National Technical University of Athens, Greece, and his Dipl.-Ing. Degree in computer engineering and information science from the University of Patras, Greece. Currently, he is the technical director of Ellemedia Technologies, where he leads R&D of end-to-end interactive multimedia services, embedded systems, and 3G/4G core network services. Since 1994 he has participated in many European co-funded projects. His research interests are in the fields of broadband wireline/wireless/mobile communications, interactive service deployment, management of IP/WDM networks, and embedded systems. He has published more than 30 papers. He has been a reviewer and principal guest editor in many journals and magazines. He is a member of the ACM and the Technical Chamber of Greece.Christos N. Capsalis was born in Greece, in 1956. He received the diploma in electrical and mechanical engineering from the National Technical University of Athens (NTUA), Athens, Greece, in 1979, the B.Sc. degree in economics from the University of Athens, Athens, Greece, in 1983, and the Ph.D. degree in electrical engineering from NTUA in 1985. He is currently a Professor at NTUA and Director of the wireless communications laboratory. His current research activities include wireless and satellite communications systems and EMC topics.     

Interference Mitigation and Joint Decoding for Uplink LDPC-Coded Relay Cooperation

This paper proposes an efficient inter- ference mitigation and joint decoding scheme for uplink LDPC-coded relay cooperation over a Rayleigh fading channel, where a concatenation of Minimum-mean-squared error linear detectors （MMSE） and BP-based joint itera- tire decoding based on the introduced treble-layer Tanner graph are effectively designed to filter and decode the cor- rupted received sequence at a base station. It is demon- strated by theoretical analysis and numerical simulations that the proposed design can well combine the gains from coding and diversity, which consequently leads to a sig- nificant performance improvement over the conventional cooperation system under the same conditions.     

无线双模数字对讲机的设计与实现

传统模拟对讲机由于频谱利用率低、抗干扰性能差、频道开放、不具有保密性等原因已经很难满足需求。文章介绍的无线双模对讲机用于改善传统模拟对讲机抗干扰及保密性差的缺点,所提双模对讲机设计方案综合了集群和无中心两种工作模式功能,具有灵活设置与抗干扰性强的优点。文中重点设计了对讲机的软硬件结构,还对音频编解码进行了讨论分析。     

江阴学院网络高清视频监控系统设计与应用

针对大学校园情况复杂、管理难度较大的特点,构建了全数字高清视频监控系统.根据系统的工程设计原则和传输要求,给出了摄像部分、传输部分、控制部分和显示记录部分的工程设计方案,论述了其系统结构、组成、功能及设备选型.该方案具有较高的通用性及实用性,为数字化校园视频监控建设提供了一种可行的方法.     

MQAM T—TCM研究

本文根据Turbo编码和TCM原理,提出一种更为合理的MQAM T－TCM实现结构,这种现实方式可推广到PSK T－TCM系统,并导出与其相应的译码算法,通过计算机模拟对其性能进行了分析,证明了改进结构的正确性。     

Turbo Code译码方法的改进

在文章中，首先介绍Turbo码的基本编译码结构和它的译码算法MAP。在此基础上，尝试对MAP算法的循环译码的后向递推的起点以及循环译码结构的最终判决条件根据实际应用情况进行改进。将译码的后向递推的起点定义为译码的前向递推的终点，并且将每一轮译码结果进行加权相加，得到最后系统输出。最后，根据MATLAB仿真的结果论证改进后的算法能减少系统的误码率。     

施肥水平对甜菜产糖量的影响

研究了甜菜生产力的适宜施肥水平，结果表明甜菜单位面积产量、产糖量与施肥量间呈二次曲线相关，以Ｎ１０Ｐ１２Ｋ１０（ｋｇ／亩）处理的甜菜产量、产糖量最高，在此施肥量范围内，甜菜产量随施肥产量增加而提高，再增加施肥量进则降低甜菜生产力。     

TMS320DM642多媒体处理系统中高性能音频功能的实现

介绍了在以新一代高性能处理器TMS320DM642为核心的多媒体处理系统中,采用音频编解码芯片TLV320AIC23实现高性能音频处理功能,详细说明了TMS320DM642多路音频串口McASP和内置集成电路总线的软硬件接口设计,并给出了TLV320AIC23初始化设置参数。     

An efficient decision feedback equalizer for the ATSC DTV receiver

In this paper an efficient decision feedback equalizer is presented for the equalization of the received signal in the eight level vestigial sideband, Advanced Television Systems Committee, digital television system, adopting a novel detection rule for symbol detection at the output of the equalizer. The conventional hard limiter is replaced by an efficient symbol detection algorithm, based on the underlying trellis coded modulated coding of the transmitted symbols. The proposed decision device has a marginal computational cost and it can be implemented using simple combinatorial and sequential logic circuitry. When the equalizer operates in the decision directed mode, the normalized least mean squared algorithm is utilized for the adaptation of the equalizer coefficients, in a “stop-and-go” like mode, triggered by a reliability signal associated to the detected symbols. The performance of the proposed method is illustrated by typical computer simulation.     

基于遗传算法的图像序列译码性能分析

Fano算法在码树上始终只跟踪一条路径,因此遭遇到比较严重的噪声干扰时,容易偏离正确路径,并且难以在较短时间内回到正确路径上来.本文提出了一种基于遗传算法的纠错序列译码算法,将遗传算法具有的全局优化的迭代进化用于序列译码中,使得译码序列不仅保留最大似然路径,也扩展一些似然度比较小的路径,使被选中的路径具备多样性,可以搜索比较宽的范围,从而尽可能跟踪到最佳路径.同时,能根据干扰的大小通过门限调节自适应地改变群体规模,达到正确而且快速搜索译码的目的.全文讨论了该算法的基本原理和实现可行性,并将这种算法用于视频图像纠错,给出了实验结果及其性能分析.