检索结果-南通市图书馆

Robust multiuser MIMO scheduling algorithms with imperfect CSI

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Information Sciences) 2012年第4期55卷 815-826页

作者： MAO JunLing 1,3,GAO JinChun 1,3,LIU YuanAn 1,3,XIE Gang 2.3 & ZHANG Jian 1,3 1 School of Electronic Engineering,beijing University of posts and {2.,beijing 100876,china 2.School of Information and Communication Engineering,beijing University of posts and {2.,beijing 100876,china 3 key Lab of Universal Wireless Communications,Ministry of Education,beijing University of posts and {2.,beijing 100876,china School of Electronic Engineering Beijing University of Posts and Telecommunications Beijing China key Lab of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing China School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing China

Robust multiuser multiple-input-multiple-output (MIMO) scheduling algorithms are proposed in this *** imperfect channel state information (CSI),traditional scheduling algorithms for the multiuser MIMO system based on the zero forcing precoding scheme will lose some performance due to the multi-user interference (MUI).In order to improve the system average throughput,we study the robust multiuser MIMO scheduling problem with imperfect *** the average capacity formula,we derive a robust factor which can transform the robust multiuser MIMO scheduling problem into the traditional one,thus most existing non-robust scheduling algorithms can be robust if this factor is *** results show that compared with the traditional algorithms,the proposed robust algorithms can improve the system average throughput significantly under the CSI error environment.

关键词： multiuser MIMO (MU-MIMO) scheduling robust imperfect CSI

Enhancing Reliability via Checkpointing in Cloud Computing Systems

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

china Communications 2017年第7期14卷 108-117页

作者： Ao Zhou Qibo Sun Jinglin Li state key {2. of networking and switching technology Beijing University of Posts and Telecommunications

Cloud computing is becoming an important solution for providing scalable computing resources via Internet. Because there are tens of thousands of nodes in data center, the probability of server failures is nontrivial. Therefore, it is a critical challenge to guarantee the service reliability. Fault-tolerance strategies, such as checkpoint, are commonly employed. Because of the failure of the edge switches, the checkpoint image may become inaccessible. Therefore, current checkpoint-based fault tolerance method cannot achieve the best effect. In this paper, we propose an optimal checkpoint method with edge switch failure-aware. The edge switch failure-aware checkpoint method includes two algorithms. The first algorithm employs the data center topology and communication characteristic for checkpoint image storage server selection. The second algorithm employs the checkpoint image storage characteristic as well as the data center topology to select the recovery server. Simulation experiments are performed to demonstrate the effectiveness of the proposed method.

关键词： cloud computing cloud service reliability fault tolerance data center network

Cross layer scheduling for real-time traffic in multiuser MIMO-OFDMA systems

在线全文

学校读者我要写书评

暂无评论

The Journal of china Universities of posts and {2. 2009年第3期16卷 24-29页

作者： SUN Qiao-yun,TIAN Hui,DONG Kun,ZHANG Ping key laboratory of Universal Wireless Communications,Ministry of Education,{2. University of posts and telecommunications,beijing 100876,china key laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

A novel cross layer scheduling algorithm is proposed for real-time （RT） traffic in multiuser downlink multiple-input multiple-output orthogonal frequency division multiple access （MIMO-OFDMA） wireless systems. The algorithm dynamically allocates resources in space, time and frequency domain based on channel state information （CSI）, users＇ quality of service （QoS） requirements and queue state information （QSI）. To provide higher data rate and spectrum efficiency, adaptive modulation and coding （AMC） is employed. The proposed algorithm can improve cell throughput and increase the number of users that can be supported while guaranteeing users＇ QoS requirements and fairness among all users. Simulation results indicate that the proposed algorithm can achieve superior performance.

关键词： MIMO-OFDMA cross layer QoS AMC

The Research on Cryptographic Schemes

在线全文

学校读者我要写书评

暂无评论

ZTE Communications 2007年第4期5卷 1-5页

作者： Zheng Shihui (Information Security Center of state key {2. of networking and switching technology, beijing University of posts and telecommunications, beijing 100876, china)

Cryptography is an important technology for information security. It mainly includes symmetric and asymmetric cryptographic algorithms and protocols. For the symmetric cryptographic algorithms, it is easy to deduce decryption keys from the encryption keys and vice versa. Because this algorithm encrypts and decrypts data very quickly, it is applicable in situations where large numbers of data have to be protected. However, for the asymmetric algorithm, extracting the secret key from the public key is computationally infeasible. Although the performance speed of the asymmetric algorithm is much slower than that of the symmetric algorithm, the asymmetric algorithm has key distribution and management advantages over the symmetric one. Moreover, it is a perfect digital signature scheme.

关键词： Hash The Research on Cryptographic Schemes

Construction of nonbinary quantum cyclic codes by using graph method

在线全文

学校读者我要写书评

暂无评论

Science in china(Series F) 2005年第6期48卷 693-702页

作者： LIU Tailin1,2.3, WEN Qiaoyan1 & LIU Zihui4 1. School of Science, beijing University of posts and {2., beijing 100876, china 2. state key laboratory of Integrated Services Network, Xidian University, Xi’an 710071,china 3. Shandong Finance Institute, Jinan 2.0014, china 4. School of Mathematical Sciences, Peking University, beijing 100871, china School of Science Beijing University of Posts and Telecommunications Beijing China state key {2. of Integrated Services Network Xidian University Xi’an China Shandong Finance Institute Jinan China School of Mathematical Sciences Peking University Beijing China

Using the graph method proposed by Schlingemann and Werner, this paper introduces a technique to construct nonbinary quantum cyclic codes and provides a specific example. We also construct the quantum codes [[8, 2. 4]... 详细信息

关键词： nonbinary quantum stabilizer codes quantum cyclic codes

Conjugate adjoining problem in braid groups and new design of braid-based signatures

在线全文

学校读者我要写书评

暂无评论

Science china(Information Sciences) 2010年第3期53卷 524-536页

作者： WANG LiCheng1,2. WANG LiHua2. CAO ZhenFu3, YANG YiXian1 & NIU XinXin1 Information Security Center, state key {2. of networking and switching technology, beijing University of posts and telecommunications, beijing 100876, china 2.ational Institute of Information and Communications technology, Tokyo 184-8795, Japan 3Trusted Digital technology {2., Shanghai Jiao Tong University, Shanghai 2.02.0, china Information Security Center State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing China National Institute of Information and Communications technology Tokyo Japan Trusted Digital technology laboratory Shanghai Jiao Tong University Shanghai China

The development of quantum computation casts serious threats to the securities of most existing public-key cryptosystems. Braid-based cryptography is one of the alternatives that have potential advantages in resisting quantum attacks. In this paper, the state of the art of braid cryptography is surveyed, and then a new cryptographic problem-conjugate adjoining problem related to braid groups is proposed. Based on this problem, we design a new braid-based signature scheme. This scheme is efficient and provably secure in the random oracle model. Further, we present the comparison between braid-based signatures and RSA-based ones. The signing process of the braid-based schemes is more efficient than that of RSA-based ones, while the verifying process of the braid-based ones is observably slow. Hence, braid-based signatures are suitable for scenarios where the signing process has to be as quick as possible but delays are permitted in the verifying process, for example, in off-line e-cash systems. The key sizes in braid-based schemes are considerably large-about 2. bits in the case of secret keys and 12. bits in the case of public keys. However, braid operations are much simpler and more efficient than modular exponential operations. Therefore, braid-based schemes can be embedded into devices with low computational ability and large memory space. The capability of braid cryptosystems to resist currently known quantum attacks is also discussed from the perspective of hidden subgroup problems.

关键词： braid group conjugate adjoining problem digital signature provable security resistance to quantum attack

Robust L2.L∞ control for uncertain singular systems with time-varying delay

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2008年第8期18卷 1015-1021页

作者： Lin Lia,*, Yingmin Jiaa, Junping Dub, Shiying Yuan c a The Seventh Research Division, beijing University, beijing 100083, {2. b beijing key laboratory of Intelligent telecommunications Software and Multimedia, beijing University of posts and telecommunications, beijing 100876, {2. c School of Electrical Engineering and Automation, Henan Polytechnic University, Jiaozuo 454000, {2. The Seventh Research Division Beijing University Beijing 100083 China beijing key {2. of Intelligent telecommunications Software and Multimedia Beijing University of Posts and Telecommunications Beijing 100876 China School of Electrical Engineering and Automation Henan Polytechnic University Jiaozuo 454000 China

We study the problem of L2.L1 control for a class of uncertain singular systems with time-delay and norm-bounded parameter uncertainties in this paper. A new delay-dependent robust stability criterion is obtained in terms of linear matrix inequalities (LMIs). Based on this criterion, a state feedback controller is designed to guarantee that the closed-loop system is regular, impulse free and stable with a prescribed L2.L1 performance satisfied for all admissible parameter uncertainties. A simulation example is included to illustrate the effectiveness of the proposed method.

关键词： L2.L1 control Singular systems Delay-dependent condition LMIs

Resource Allocation and User Association for HTTP Adaptive Streaming in Heterogeneous Cellular Networks with Small Cells

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

china Communications 2016年第9期13卷 1-11页

作者： Jiang Liu state key {2. of networking and switching technology Beijing University of Post and TelecommunicationsBeijing 100876China Department of Systems and Computer Engineering Carleton UniversityOttawaONCanada beijing Advanced Innovation Center for Future Internet technology Beijing 100124China

Video streaming,especially hypertext transfer protocol based(HTTP) adaptive streaming(HAS) of video,has been expected to be a dominant application over mobile networks in the near future,which brings huge challenge for the mobile *** some works have been done for video streaming delivery in heterogeneous cellular networks,most of them focus on the video streaming scheduling or the caching strategy *** problem of joint user association and rate allocation to maximize the system utility while satisfying the requirement of the quality of experience of users is largely *** this paper,the problem of joint user association and rate allocation for HTTP adaptive streaming in heterogeneous cellular networks is studied,we model the optimization problem as a mixed integer programming *** to reduce the computational complexity,an optimal rate allocation using the Lagrangian dual method under the assumption of knowing user association for BSs is first *** we use the many-to-one matching model to analyze the user association problem,and the joint user association and rate allocation based on the distributed greedy matching algorithm is ***,extensive simulation results are illustrated to demonstrate the performance of the proposed scheme.

关键词： heterogeneous cellular networks user association rate allocation http adaptive streaming matching algorithm

The Research on Audio Information Hiding technology

在线全文

学校读者我要写书评

暂无评论

ZTE Communications 2007年第4期5卷 6-9页

作者： Yuan Kaiguo Yang Yu Yang Yixian (state key {2. of networking and switching technology, beijing University of posts and telecommunications, beijing 100876, china)

Audio information hiding technology is an important branch of stenography. This article introduces the basic concepts, principles, characteristics and the typical models of the audio information hiding. It then classifies the audio information hiding methods, according to the domain used by them including time, frequency, Discrete Cosine Transform (DCT), Discrete Wavelet Transform (DWT) and the compressed., and discusses several mainstream algorithms in various domains. It finally points out that the audio information hiding technology cannot solve the problem of re-record attacks, but it also brings forward the possible solutions to this problem.

关键词： The Research on Audio Information Hiding technology LSB DCT IEEE