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Effective capacity region of two-user opportunistic spectrum access

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science china(Information sciences) 2011年第9期54卷 1928-1937页

作者： xu YuHua,WANG JinLong & WU QiHui institute of communications engineering,pla university of science and technology,nanjing 210007,china institute of communications engineering PLA University of Science and Technology Nanjing China

The effective capacity region of the two-user opportunistic spectrum access (OSA) system in Rayleigh fading environment is derived in this *** OSA is a contemporary research topic,little attention has been given to the capacity analysis under quality-of-service (QoS) ***,we use the effective capacity,which is a powerful tool to analyze the QoS requirements in wireless communication systems,to study the sustainable packet arrival rate of the secondary users while meeting statistical QoS *** derive the effective capacity region of the two-user OSA system and propose a method to obtain the capacity region *** addition,by combining the finite state channel model and the activity of the primary user,an extended finite state channel model for the two-user OSA system is also proposed.

关键词： cognitive radio opportunistic spectrum access effective capacity

Global Convergence of the Conjugate Descent Method Under a kind of Inexact Line Search Conditions

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Systems science and Systems engineering 2002年第1期11卷 1-5页

作者： xu ze-shui institute of sciences, pla university of science and technology, nanjing 210016, china institute of sciences PLA University of Science and Technology Nanjing 210016 China

The conjugate descent (CD) was introduced by Fletcher. This paper proves that a kind of inexact line search conditions can ensure the global convergence of the CD method.

关键词： the conjugate descent (CD) line search

Research on Consistency of the Complex Interval Judgement Matrix in AHP

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Systems science and Systems engineering 2000年第2期10卷 159-163页

作者： xu ze\|shui pla university of science and technology, nanjing 210016, china

The weighted geometric mean method(WGMM) has been the most commonly used method in the analytic hierarchy process(AHP) for combining individual opinions to form a group opinion. In this paper, we study the consistency of the WGMM in group decision and prove that the weighted geometric mean complex interval judgement matrix (WGMIM) is of acceptable consistency under the condition that all interval matrices for the same decision\|making problem are of acceptable consistency. Thus, research on consistency of group decision in AHP is further developed and a theory basis for the application of the WGMM is also made.

关键词： the analytic hierarchy process(AHP) interval judgement matrix consistency

The Class of the Generalized αk-Major Efficient Solutions for Multi-objective Programming

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Journal of Systems science and Systems engineering 2001年第4期13卷 439-442页

作者： xu ze-shui institute of sciences, pla university of science and technology, nanjing 210016, Jiangsu, china institute of sciences PLA University of Science and TechnologyNanjing 210016 Jiangsu China

This paper proposes the concepts of generalized αk-major efficient solutions and generalized αk- major optimal solutions for multi-objective programming, and studies their some important properties.

关键词： multi-objective programming generalized αk-major efficient solutions generalized αk-major optima1 solutions

Two Methods for Deriving Members′Weights in Group Decision Making

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Journal of Systems science and Systems engineering 2001年第1期13卷 15-19页

作者： xu ze\|shui pla university of science and technology nanjing, Jiangsu 210016, china pla university of science and technology nanjing Jiangsu 210016 China

：The Analytic Hierarchy Process is a powerful technique for group decision making. Both theWeighted Arithmetic Mean Method (WAMM) and Weighted Geometric Mean Method (WGMM) are themost common group preference aggregation methods in AHP. In order to use the WAMM and WGMM, onehas to find the weights to be assigned to the members of the group. This is often a difficult task, especiallyso if the group is large as in the case of public policy decisions. These situations need an objective method toderive members'weights. But a few studies are available in the literature. Based on judgement matrices anderror analyses, this paper presents two practical and efficient methods for addressing such situations. Somenumerical examples are also given.

关键词： group decision making judgement matrix weight

ROBUST AND FAST FREQUENCY OFFSET ESTIMATION FOR OFDM BASED SATELLITE COMMUNICATION

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Journal of Electronics(china) 2009年第1期26卷 45-51页

作者： Wei Li xu Youyun Cai Yueming institute of communications engineering PLA University of Science ＆ Technology Nanjing 210007 China

A pilot-aided Orthogonal Frequency Division Multiplexing (OFDM) frequency offset es- timator designed for satellite communication system is proposed in the paper. The estimator focuses on the acquisition of the integer part of carrier frequency offset and the acquisition range is as large as the whole signal bandwidth. Making full use of the phase difference between received pilot and local ref- erential pilot, a fast estimation is obtained. Compared with existing method, our method can also work well even in SNR as low as 0dB. Simulations verify the good performance of our method.

关键词：正交评分复用技术 OFDM 估计人造卫星

Power-Domain Collision-Tolerant Random Access Method with Auxiliary Beam for Satellite Internet of Things:A New Solution

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china communications 2024年第8期21卷 236-248页

作者： xu Yuanyuan Liu Ziwei Bian Dongming Zhang Gengxin School of communications and Information engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China institute of communications engineering PLA University of Science and TechnologyNanjing 210007China

There are numerous terminals in the satellite Internet of Things(IoT).To save cost and reduce power consumption,the system needs terminals to catch the characteristics of low power consumption and light *** regular random access(RA)protocols may generate large amounts of collisions,which degrade the system throughout *** near-far effect and power control technologies are not applicable in capture effect to obtain power difference,resulting in the collisions that cannot be *** fact,the optimal design at the receiving end can also realize the condition of packet power domain separation,but there are few relevant *** this paper,an auxiliary beamforming scheme is proposed for power domain signal *** adds an auxiliary reception beam based on the conventional beam,utilizing the correlation of packets in time-frequency domain between the main and auxiliary beam to complete signal *** roll-off belt of auxiliary beam is used to create the carrier-to-noise ratio(CNR)*** paper uses the genetic algorithm to optimize the auxiliary beam *** results show that the proposed scheme outperforms slotted ALOHA(SA)in terms of system throughput per-formance and without bringing terminals additional control burden.

关键词： beamforming non-orthogonal multiple access random access satellite Internet of Things

Wireless Cooperative Mesh Network:A New Architecture for Network Convergence

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ZTE communications 2008年第3期6卷 20-23页

作者： Yang Wendong,Cao Yueming,xu Youyun(institute of communications engineering,pla university of science and technology,nanjing 210007,china)

The convergence of heterogeneous wireless networks is a trend in the evolution of wireless networks.A new architecture for network convergence,named Wireless Cooperative Mesh Network,is proposed to solve such emerging problems in convergence as transmission mode selection,load balancing,routing and *** new architecture is based on the structure of Wireless Mesh Networks(WMNs),and cooperative communication is also employed to further optimize its structure and upgrade its *** can thus obtain advantages of both the Mesh technology(high spectrum efficiency and dynamic self-organization) and cooperative communication(high diversity gain and high energy efficiency).The new architecture serves as an efficient solution for wireless network convergence.

关键词： Mesh Wireless Cooperative Mesh Network WMNs

A COLLABORATIVE SPECTRUM SENSING SCHEME USING FUZZY COMPREHENSIVE EVALUATION IN COGNITIVE RADIO

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Journal of Electronics(china) 2009年第3期26卷 326-331页

作者： Yang Wendong Ye Yuhuang Cai Yueming xu Youyun institute of communications engineering PLA University of Science and Technology Nanjing 210007 China institute of Microwave Communication Fuzhou University Fuzhou 350002 China

Cognitive Radio(CR) is a promising technology to solve the challenging spectrum scarcity ***, to implement CR, spectrum sensing is the groundwork and the *** this paper, a collaborative spectrum sensing scheme using fuzzy comprehensive evaluation is *** final sensing decision of the proposed scheme is based on the combination of distributed sensing results of different Secondary Users(SUs).To improve the reliability of the sensing decision, the combination procedure takes into account the credibility of each SU, which is evaluated using fuzzy comprehensive *** effect of the presence of malicious SUs and malfunctioning SUs on the performance of the proposed scheme is also *** efficiency of the scheme is validated through analysis and simulation.

关键词：模糊综合评价遥感计划认知无线电光谱协同高可靠性挑战性分布式