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Progress in Natural Science:Materials International 2009年第9期19卷 1141-1146页

作者： Qiaoyun Sun, Hui Tian *, Shuang Wang, Kun Dong, Ping Zhang Key Laboratory of Universal Wireless communication, Ministry of Education, Wireless Technology Innovation Institute, beijing university of posts & Telecommunications, beijing 100876, china [a]Key Laboratory of Universal Wireless communication Ministry of Education Wireless Technology Innovation Institute Beijing University of Posts & Telecommunications Beijing 100876 China

In this paper, subcarrier and power allocation problems for multiuser downlink MIMO-OFDMA of the FuTURE B3G TDD system are investigated. For the reciprocity of the TDD channel, the channel state information can be employed at the transmitter, thus eigen beamforming can be implemented efficiently. With the goal of minimizing the total transmit power under the condition that the QoS requirement of each user can be guaranteed, a novel dynamic resource allocation scheme is proposed to exploit the multiuser diversity gain. The proposed algorithm involves adaptive subcarrier allocation, adaptive modulation and eigen beamforming and achieves significant improvement in overall system performance. Based on the proposed scheme, a modified bit and power allocation is developed. The modified scheme reduces the computational complexity at little expense of system performance. Numerical simulations show that the proposed algorithm and the modified scheme can decrease the total transmit power effectively.

关键词： Adaptive modulation and coding Dynamic resource allocation Eigen beamforming MIMO–OFDMA

Total Coloring of G×P_n and G×C_n

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The Journal of china Universities of posts and Telecommunications 2000年第1期7卷 13-15页

作者： YANG Yi-xian, LIU Huan-ping (information Security Center, Department of information engineering, beijing {4. of posts and Telecommunications, beijing 100876, P. R. china ) information Security Center Department of Information Engineering Beijing University of Posts and Telecommunications Beijing 100876 P. R. China

It is proved that if G is a (+1)-colorable graph, so are the graphs G×Pn and C×Cn, where Pn and Cn are respectively the path and cycle with n vertices, and the maximum edge degree of the graph. The exact chromatic numbers of the product graphs and are also presented. Thus the total coloring conjecture is proved to be true for many other graphs.

关键词： combinatorial problems product graph total coloring total chromatic number

communication Software Reuse and Its Supporting Environment

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The Journal of china Universities of posts and Telecommunications 1998年第1期5卷 76-77页

作者： Zhou Chen directed by Chen Junliang (Department of information engineering, beijing university of {4. and Telecommunications, beijing 100876, P. R. china)

Summary of Software Reuse What we mean 'software reuse' is that we use those software components that were developed before in the new environment. Increasing the productivity and reliability of software is an important task in the development of software. One of the most promising techniques for achieving a significant level of improvement is reuse. The reuse process occurs in every phase of software life cycle: analysis, design, coding, testing, and maintenance. The technologies applied to the reusability can be divided into two major groups depending on the nature of the components being reused. These two major groups are composition approach and generation approach. Both of the approaches have their advantages and drawbacks and there is no agreement upon a unique approach to reusability. We choose composition approach. In this paper, we focus on the research of switching software reuse. There has been no report on the research of communication software reuse in china. The research was carried out in Japan and U.S.A. in the middle of 1980′s. Some references report that there are many advantages in using object oriented language C++ in the development of 5ESS switching system. The software reusability is high and the productivity is also greatly improved. It seems that every switching system has its own software supporting tools or environment. The aim is the same and the reusing technologies are somewhat different. Three main reuse methods are listed below: (1) Paradigm method; (2) Knowledge Base method; (3) Object oriented method. 2 Main Researches (1) Research on the integrated environment for SDL (IES). (2) Convert Abstract Data Types(ADT) in SDL specification to CHILL implementation; By using IF_THEN_ELSE rewriting rules, we prove the correctness of conversion. (3) Introduce the concept of reuse into SDL, and design and implement a SDL ADT/CHILL reusable component library. We focus on the Di

关键词： SDL specification software reuse object orientation

Wavelet Packets Analysis Based on IIR Two-channel Bi-orthogonal Filter Banks

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The Journal of china Universities of posts and Telecommunications 1998年第2期5卷 41-46页

作者： Yan Guixia and Zhao Eryuan (Institute of Telecommunication engineering, beijing university of {4. and Telecomm., beijing, 100876.P.R. china)

A framework of IIR two-channel bi-orthogonal filter banks is presented. The design of the analysis/synthesis systems reduces to the design of a single transfer function. The wavelet bases corresponding to the IIR maximally flat filters are generated. Use the wavelet bases in wavelet packets analysis, take information entropy function as information cost function, adjust the best bases dynamically, and the section of signal's spectramfits its characteristics well. A lot of audio signals are processed. Compared to that of the wavelet transform and the wavelet packet transform using the Daubechies' wavelet which has the same order with our IIR wavelet, the properties of our system are better

关键词： two-channel bi-orthogonal filter banks bi-orthogonal wavelet wavelet transform wavelet packet transform intonation costhnction the best bases

Performance Analysis of Interconnected communication Networks

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The Journal of china Universities of posts and Telecommunications 1998年第1期5卷 72-72,75页

作者： Wang Jianli directed by Zhou Jiongpan (Department of information engineering, beijing university of {4. and Telecommunications, beijing 100876, P. R. china)

As the means for communication of users in different communication networks and network resource sharing, communication network interconnection has been paid great attention to in recent years. The performance analysis of internetworks is very important in communication network interconnection, for it is the basis for the study of other problems concerned. The main contribution of this paper is a wide and deep study of performance of internetwork, the construction of systematic performance analysis method for arbitrary internetworks, and of queuing model for gateways. In this paper, the performance analysis of internetwork with arbitrary topology is studied for the first time, and a new method - Node Equivalence of Subnetworks (NES) is proposed. The key step of this method is the node equivalence of subnetworks of all kinds, so we first deeply study the node equivalence, and develop two models for node equivalence. Then we study the node equivalence of CSMA/CD and SLOTTED ALOHA systems by using these models. The results show that the NES method is a systematic method which is suitable for performance analysis of any type of internetworks. The proposed equivalence models is usable with good approximation. The queuing model of gateway is first widely studied in this paper. The queuing model for gateways with packet fragmentation and reassembly is studied for the first time and the analysis method, proposed. In the analysis, two modeling tools, Reversed Switched Poisson Process (RSPP) and Switched Determined Process (SDP), are proposed and RSPP/M/1 queue and SDP/D/1 queue, analyzed. A new method-minislot method is proposed and used for the study of SDP/D/1 queue and performance of ATM multiplexer. In this paper, the interdeparture time distribution of ATM network under some input traffic models is studied and the expression, derived. These results can be used for both performance evaluation of ATM network and the performance of ATM networks intercon

关键词： interconnected communication network internetworks gateway subnetworks node equivalence

Auto-Cross-and Triple-Correlations of Sequences

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The Journal of china Universities of posts and Telecommunications 1996年第2期3卷 1-8页

作者： Yang Yixian(Department of information engineering, beijing university of {4. and Telecommunications, beijing 100088, P. R. china) Department of information engineering Beijing University of Posts and Telecommunications Beijing 100088 P. R. China

Autocorrelations, crosscorrelations and triple correlations are three important concepts for signal design and analysis, although the triple ones are not so popular as auto-and cross-ones. This poper concentrates on designing new polyphase sequences with good correlations and on recovering signals from their triple correlations. The close relationship between Costas armys and the triple correlations Of m-sequences are initially recognized.

关键词： s: autocorrelation crosscorrelation triple correlation sequences costas arrays CDMA

Performance evaluation of channel inversion precoding for downlink multi-user MIMO system

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The Journal of china Universities of posts and Telecommunications 2009年第5期16卷 20-24页

作者： CHEN Zhi-yong , WANG Wen-bo, PENG Mu-gen, LI Ren Wireless Signal Processing and Network Laboratory, Key Laboratory of Universal Wireless communication, Ministry of Education, beijing university of posts and Telecommunications, beijing 100876, china [a]Wireless Signal Processing and Network Laboratory Key Laboratory of Universal Wireless communication Ministry of Education beijing university of posts and Telecommunications beijing 100876 china

In downlink multi-user multi-input multi-output （MU-MIMO） system, not every user （user equipment （UE）） can calculate accurately signal to interference and noise ratio （SINR） without prior knowledge of the other users＇ precoding vector. To solve this problem, this article proposes a channel inversion precoding scheme by using the lower bound of S1NR and zero-forcing （ZF） algorithm. However, the SINR mismatch between lower bound SINR and actual SINR causes the inaccurateness of adaptive modulation and coding （AMC）. As a result, it causes degradation in performance. Simulation results show that channel inversion precoding provides lower throughput than that of single user multi-input multi-output （SU-MIMO） at high signal-to-noise ratio （SNR）（〉14.dB）, due to the SINR mismatch, although the sum-rate of channel inversion precoding is higher than that of SU-MIMO at full SNR regime.

关键词： MU-MIMO channel inversion precoding CQI feedback AMC lower bound S1NR zero-forcing

The Technology of Smart Antenna in IEEE 802.16

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The Technology of Smart Antenna in IEEE 802.16

A New Wavelength Selective Photoreceiver

2006北京地区高校研究生学术交流会

作者： Luo Dan Guo Li Xu Guang (school of information engineering, beijing {4. of posts and Telecommunications, beijing 100876, china) (school of information engineering, beijing {4. of posts and elecommunications, beijing 100876, china) (school of information engineering, beijing {4. of posts and elecommunications, beijing 100876, china)

As is known to us, the technology of smart antenna in the mobile communication system would increase the capacity and spectrum efficiency, extend the system coverage etc. On the other hand, broadband wireless access (BWA) has become the best way to meet escalating business demand for rapid Internet connection and integrated data, voice and video services. IEEE 802.16 has mentioned the technology of smart antenna as optional part but not in very detail. The purpose of this paper is to bring forward a MAC protocol of base station (BS) with multi-beam antenna system and subscribers (SS) with adaptive array systems to accomplish the access control practically.

关键词： IEEE 802.16 MAC Smart Antenna

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Chinese Journal of Lasers 2000年第5期9卷 51-55页

作者： LIU Kai HUANG Yongqing REN Xiaomin LI Jianxin GUO Wei (Optical communication Center, beijing university of posts and Telecommunications, beijing 100876, china)MA Xiaoyu KANG Xuejun LIAO Qiwei (Institute of Semiconductor, The Chinese Academy of 北京邮电大学北京中科院半导体所北京

A new kind of wavelength selective photoreceiver is proposed. It was constructed by a Fabry Perot (F P) etalon filter and a resonant cavity enhanced (RCE) photodetector. The photoreceiver′s spectral response is determined by the F P etalon filter with a FWHM of less than 4.nm. Moreover, with such a photoreceiver, the transmission loss of the F P etalon filter can be compensated to some extent. And this will benefit its applications.

关键词： wavelength selection photodetector WDM and optoelectronics device