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SQUARE attack on block ciphers with low algebraic degree

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Science china(Information Sciences) 2010年第10期53卷 1988-1995页

作者： SUN Bing 1 , LI RuiLin 1 , QU LongJiang 1,3 & LI Chao 1,2,3 1 Science College of national university of Defense Technology, Changsha 410073, china 2 State Key laboratory of Information Security, Graduate university of Chinese Academy of Sciences, Beijing 100049, china 3 national mobile communications research laboratory, southeast university, nanjing 210096, china Science College of national university of Defense Technology Changsha China national mobile communications research laboratory Southeast University Nanjing China State Key laboratory of Information Security Graduate University of Chinese Academy of Sciences Beijing China

By using an algebraic method, the mathematical foundation of SQUARE attack is studied in this paper. We point out that a SQUARE distinguisher exists if and only if the degree of the polynomial function between n-bit input which is active and n-bit output which is balanced is 2 n-2. And the algebraic method can also be used to determine the property of a balanced set after passed through a nonlinear S-box, by which in some cases we can find a SQUARE distinguisher with more rounds. The validity of SQUARE attack and the influence of the choice of S-box are also studied. If the round function of a Feistel cipher has a low algebraic degree, a SQUARE attack cannot recover the right keys in some special cases. However, SQUARE attack on SPN ciphers always holds. The relations among SQUARE attack and some other cryptanalytic method are studied, showing that if a cipher is breakable by SQUARE attack, then it is also breakable by the interpolation attack.

关键词： SQUARE attack interpolation attack integral attack block cipher

Low-complexity distributed differential spacetime coding scheme for amplify-and-forward cooperative networks

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Science in china(Series F) 2009年第8期52卷 1418-1427页

作者： YU XiangBin1,2, BI GuangGuo3 & XU WeiYe4 1 College of Information Science and Technology, nanjing university of Aeronautics and Astronautics, nanjing 210016, china 2 Department of Electronic Engineering, City university of Hong Kong, Hong Kong, china 3 national mobile communications research laboratory, southeast university, nanjing 210096, china 4 Department of Communication Engineering, nanjing Institute of Technology, nanjing 211167, china College of Information Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing China Department of Electronic Engineering City University of Hong Kong Hong Kong China national mobile communications research laboratory Southeast University Nanjing China Department of Communication Engineering Nanjing Institute of Technology Nanjing China

By introducing a space-time coding scheme based on amicable orthogonality, we develop a distributed differential space-time coding scheme with the amplify-and-forward （AF） method for wireless cooperative networks. The scheme requires no knowledge of the channel state information at both transmitters and receivers, and effectively decreases the realization complexity due to no channel estimation. Moreover, it has lower decoding complexity and higher coding advantage than the existing scheme, thus avoiding the shortcoming of exponential decoding complexity of some existing schemes. According to the pairwise error probability （PEP） analysis of the system, the power allocations of source and relay terminals are jointly optimized, and as a result, the PEP is minimized, which will provide a helpful guideline for system design. Numerical calculation and simulation results show that the developed scheme is superior to the existing scheme. Moreover, the scheme with optimal power allocation yields obvious performance improvement over that with equal power allocation.

关键词： differential space-time coding cooperative communication amplify-and-forward method power allocation

Decoding algorithms for shortened-extended turbo product codes in WiMAX systems

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Science in china(Series F) 2009年第12期52卷 2415-2423页

作者： XU ChangLong1,3,4, YANG Wei1,2 & YE WeiChen4 1 State Key laboratory of Networking and Switching Technology, Beijing university of Posts and Telecommunications, Beijing 100044, china 2 State Key laboratory of Rail Traffic Control and Safety, Beijing Jiaotong university, Beijing 100044, china 3 national mobile communications research laboratory, southeast university, nanjing 210096, china 4 Intel Corporation, Beijing Kerry Center, Guanghua Road 1, Beijing 100020, china State Key laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing China national mobile communications research laboratory Southeast University Nanjing China Intel Corporation Beijing Kerry Center Beijing China State Key laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China

The component codes of turbo product codes in WiMAX systems are extended Hamming codes and single parity check codes as well as their shortened forms, In this paper, three novel iterative decoding algorithms based on Chase, MAP algorithms and their combination are proposed for shortened-extended turbo product codes. The iterative decoding algorithm based on Chase algorithm is proposed to reduce the decoding complexity without any performance loss. An efficient MAP algorithm is then proposed to decode the component codes of shortened single parity check codes and shortened-extended Hamming codes. A comprehensive performance comparison of the proposed decoding schemes is conducted for three typical classes of turbo product codes in WiMAX OFDMA systems. The suitable decoding algorithms are recommended for different classes based on the simulation results.

关键词： block code product code iterative decoding

A survey of next generation mobile communications researchin china

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Chinese Science Bulletin 2011年第5期56卷 2875-2888页

作者： TIAN JinFeng 1,2 , ZHENG XiaoYing 2,3 , HU HongLin 1,2 YOU XiaoHu 1,3 1 Shanghai research Center for Wireless communications (WiCO), Shanghai 200335, china 2 Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050, china 3 national mobile communications research laboratory, southeast university (SEU), nanjing 210096, china Shanghai research Center for Wireless communications (WiCO) Shanghai China Shanghai Institute of Microsystem and Information Technology (SIMIT) Chinese Academy of Sciences (CAS) Shanghai China national mobile communications research laboratory Southeast University (SEU) Nanjing China

With the rapid development of wireless communication networks, the fourth generation (4G) has emerged to move beyond the limitations of the third generation (3G), with increased bandwidth, enhanced quality of services, and reduced costs of resources. In this paper, we discuss the key technologies of 4G and focus on surveying the ongoing research in 4G communications in china. The 4G technologies under investigation include multicarrier transmission, multiple antenna techniques, carrier aggregation, relays, cognitive radio, distributed antenna systems, network convergence, and network self-optimization. These technologies are the building blocks of 4G and contribute largely to the requirements of International mobile Telecommunications Advanced (IMT-Advanced). For each technology, its benefits, research topics, and some existing approaches are examined. Finally, we briefly discuss the challenges and future research issues in 4G systems.

关键词：下一代移动通信中国无线通信网络分布式天线系统 4G系统多载波传输国际移动通信认知无线电

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无线个域网应用环境下速率自适应算法的研究

通信学报 2004年第4期25卷 160-167页

作者：叶芝慧沈连丰沈克勤陈锦泰东南大学移动通信国家重点实验室江苏南京210096 解放军理工大学指挥自动化学院江苏南京210007 香港中文大学电子工程学系

首先对无线个域网(WPAN)应用环境下的干扰模型进行了分析,在此基础上提出了在WPAN工作的系统中引入速率自适应控制算法以提高诸系统的抗干扰性能,并减小对系统内其它设备及不同系统间设备的相互干扰.文章对自适应速率控制算法进行了分析... 详细信息

首先对无线个域网(WPAN)应用环境下的干扰模型进行了分析,在此基础上提出了在WPAN工作的系统中引入速率自适应控制算法以提高诸系统的抗干扰性能,并减小对系统内其它设备及不同系统间设备的相互干扰.文章对自适应速率控制算法进行了分析,然后以蓝牙系统为例,给出了自适应速率控制算法对蓝牙系统性能改善的程度,重点讨论了对系统误比特率的影响.仿真结果显示,在理想反馈信道条件下,随着单信道信噪比的改善,自适应速率控制系统的最佳误比特率比固定速率传输系统有1～3个数量级的改善;即使采用简单的双速率自适应控制系统,也可以得到1～2个数量级的改善.由此得到的结果同样可应用于其它工作于无线个域网的系统.

关键词：无线个域网自适应速率控制固定速率系统蓝牙系统 IEEE 802.11b

Hierarchically Distributed Optimization with a Flexible and Complexity-Reducing Algorithm

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Journal of Systems Science & Complexity 2024年

作者： LIANG Shu ZHANG Lei WEI Yiheng LIU Yemo 1.Department of Control Science and Engineering, Tongji university 2.Shanghai research Institute for Intelligent Autonomous Systems 3.School of Mathematics, southeast university 4.Beijing Aerospace Automatic Control Institute Department of Control Science and Engineering Tongji University Shanghai research Institute for Intelligent Autonomous Systems School of Mathematics Southeast University Beijing Aerospace Automatic Control Institute

In this paper, the authors consider distributed convex optimization over hierarchical networks. The authors exploit the hierarchical architecture to design specialized distributed algorithms so that the complexity can be reduced compared with that of non-hierarchically distributed algorithms.To this end, the authors use local agents to process local functions in the same manner as other distributed algorithms that take advantage of multiple agents' computing resources. Moreover, the authors use pseudocenters to directly integrate lower-level agents' computation results in each iteration step and then share the outcomes through the higher-level network formed by pseudocenters. The authors prove that the complexity of the proposed algorithm exponentially decreases with respect to the total number of pseudocenters. To support the proposed decomposition-composition method for agents and pseudocenters, the authors develop a class of operators. These operators are generalizations of the widely-used subgradient based operator and the proximal operator and can be used in distributed convex optimization. Additionally, these operators are closed with respect to the addition and composition operations; thus, they are suitable to guide hierarchically distributed design and analysis. Furthermore,these operators make the algorithm flexible since agents with different local functions can adopt suitable operators to simplify their calculations. Finally, numerical examples also illustrate the effectiveness of the method.

关键词：

中国政治经济学年度发展报告（2023）（下）

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政治经济学评论 2024年第3期 90+207-208页

作者： Center for Studies of Contemporary Political Economy,research Institute for 21st-Century Marxism,Nankai university·university of Chinese Academy of Social Science Center for Teaching and research on Capital,Renmin university of china national Institute of Socialist Political Economy with Chinese Characteristics,Renmin university of china 南开大学·中国社会科学院大学21世纪马克思主义研究院当代政治经济学研究中心中国人民大学《资本论》教学与研究中心中国人民大学全国中国特色社会主义政治经济学研究中心

编者按2023年，高质量发展扎实推进，新质生产力加快形成，我国经济总体回升向好，圆满实现发展主要预期目标。为针对性地破解经济恢复发展中的难题，聚焦推进中国式现代化进程中的重点、难点问题，中国政治经济学界开展系统深入研究，...

编者按2023年，高质量发展扎实推进，新质生产力加快形成，我国经济总体回升向好，圆满实现发展主要预期目标。为针对性地破解经济恢复发展中的难题，聚焦推进中国式现代化进程中的重点、难点问题，中国政治经济学界开展系统深入研究，取得系列代表性成果。为准确刻画学界研究进展和轨迹，推动中国经济学理论体系的构建和完善，本刊精选议题如期奉上《中国政治经济学年度发展报告（2023）》。自2010年起，本刊连续十四年发布《中国政治经济学年度发展报告》，“年度发展报告”专栏已成为本刊标志性特色栏目。2023年报告聚焦12个专题，分为（上）（下）两篇，其中专题1—6于报告（上）篇刊登，专题7—12由报告（下）篇刊登。2023年报告（下）选题如下：

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Blind estimation of multipath delays in OFDM systems

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Science china(Information Sciences) 2012年第6期55卷 1397-1401页

作者： SHENG Bin & YOU XiaoHu national mobile communications research laboratory,southeast university,nanjing 210096,china national mobile communications research laboratory Southeast University Nanjing China

In order to coherently detect the transmitted data symbols,an orthogonal frequency division multi-plexing (OFDM) receiver requires reliable identification and equalization of the experienced wireless multipath fading channels.The information of path delays plays an important role in the procedure of identification and equalization.The need for high data rates motivated the search for blind identification and equalization methods because they save bandwidth by avoiding the use of training sequences.In OFDM systems,multipath fading channels introduce interference between adjacent symbols which can be prevented by inserting a cyclic prefix (CP) before each symbol.In this paper,we find that the power of the interference in the CP interval can be estimated by using the circular convolution and based on the variations of the interference power,the time delay of each path can be estimated blindly.

关键词： multipath delay cyclic prefix OFDM

Multi-user MIMO downlink eigen-mode transmission over jointly correlated MIMO channels

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Science china(Information Sciences) 2011年第10期54卷 2124-2137页

作者： LI Xiao ,JIN Shi & GAO XiQi national mobile communications research laboratory,southeast university,nanjing 210096,china national mobile communications research laboratory Southeast University Nanjing China

The study of multi-user multiple-input multiple-output (MU-MIMO) systems has emerged recently as an important research topic because such systems have the potential to combine the high capacity that can be achieved through MIMO processing with the benefits of spatial-division multiple-access.However,receiver and transmitter channel state information (CSI) is generally required,especially for the downlink channel.In this paper,MU-MIMO downlink transmission systems with statistical CSI at the transmitter are studied for jointly correlated MIMO channels.Eigen-mode space division multiple access transmission is derived based on the maximization of the ergodic sum rate,and two eigen-mode power allocation algorithms are proposed using matrix permanent and convex optimization theory.The new algorithms can overcome the limitations of the existing multi-user downlink transmission algorithm in practical applications.

关键词： MIMO eigen-mode multi-user downlink