检索结果-内蒙古大学图书馆

Secrecy Rate Beamforming for Multicell Networks With Information and Energy Harvesting

IEEE TRANSACTIONS ON SIGNAL PROCESSING 2017年第3期65卷 677-689页

作者： Nasir, Ali Arshad Hoang Duong Tuan Duong, Trung Q. Poor, H. Vincent King Fahd Univ Petr & Minerals Dept Elect Engn Dhahran 31261 Saudi Arabia Univ Technol Sydney Fac Engn & Informat Technol Broadway NSW 2007 Australia Queens Univ Belfast Sch Elect Elect Engn & Comp Sci Belfast BT7 1NN Antrim North Ireland Princeton Univ Dept Elect Engn Princeton NJ 08544 USA

Considering a multicell network for the secure wireless information and power transfer, this paper studies the joint design of transmit beamformers at the base stations (BSs) and receive signal splitting ratios at the end users' equipment (UE). The primary concern in this work is the network internal security, where there may be a single multiantenna eavesdropper or there is a risk that any near user may accidentally eavesdrop on the received signal of any far user. The objective is to maximize the minimum secrecy user rate under BS transmit power and UE minimum harvested energy constraints. New path-following algorithms are proposed for computational solutions of these difficult nonconvex optimization problems. Each iteration involves one simple convex quadratic program. Numerical results confirm that the proposed algorithms converge quickly after few iterations having a low computational complexity.

关键词： Secure communication secrecy rate energy harvesting nonconvex programming wireless information and power transfer signal splitting transmit beamforming

来源：评论

学校读者我要写书评

暂无评论

Secure and Energy-Efficient Beamforming for Simultaneous Information and Energy Transfer

引用

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2017年第11期16卷 7523-7537页

作者： Nasir, Ali Arshad Hoang Duong Tuan Duong, Trung Q. Poor, H. Vincent King Fahd Univ Petr & Minerals Dept Elect Engn Dhahran Saudi Arabia Univ Technol Sydney Sch Elect & Data Engn Broadway NSW 2007 Australia Queens Univ Belfast Belfast BT7 1NN Antrim North Ireland Princeton Univ Dept Elect Engn Princeton NJ 08544 USA

Some next-generation wireless networks will likely involve the energy-efficient transfer of information and energy over the same wireless channel. Moreover, densification of such networks will make the physical layer more vulnerable to cyber attacks by potential multi-antenna eavesdroppers. To address these issues, this paper considers transmit time-switching (TS) mode, in which energy and information signals are transmitted separately in time by the base station (BS). This protocol is not only easy to implement but also delivers the opportunity for multi-purpose beamforming, in which energy beamformers can be used to jam eavesdroppers during wireless power transfer. In the presence of imperfect channel estimation and multi-antenna eavesdroppers, the energy and information beamformers and the transmit TS ratio are jointly optimized to maximize the worst-case user secrecy rate subject to energy constrained users' harvested energy thresholds and a BS transmit power budget. New robust path-following algorithms, which involve one simple convex quadratic program at each iteration are proposed for computational solutions of this difficult optimization problem and also the problem of secure energy efficiency maximization. The latter adds further complexity due to additional optimization variables appearing in the denominator of the secrecy rate function. Numerical results confirm that the performance of the proposed computational solutions is robust against channel uncertainties.

关键词： Secrecy rate secrecy energy efficiency wireless power transfer time switching beamforming nonconvex programming

来源：评论

学校读者我要写书评

暂无评论

Joint Beamforming and Antenna Selection for Sum Rate Maximization in Cognitive Radio Networks

引用

IEEE COMMUNICATIONS LETTERS 2017年第6期21卷 1369-1372页

作者： Van-Dinh Nguyen Nguyen, Chuyen T. Nguyen, Hieu V. Shin, Oh-Soon Soongsil Univ Dept ICMC Convergence Technol Seoul 06978 South Korea Soongsil Univ Sch Elect Engn Seoul 06978 South Korea Hanoi Univ Sci & Technol Sch Elect & Telecommun Hanoi Vietnam

This letter studies joint transmit beamforming and antenna selection at a secondary base station (BS) with multiple primary users (PUs) in an underlay cognitive radio multiple-input single-output broadcast channel. The objective is to maximize the sum rate subject to the secondary BS transmit power, minimum required rates for secondary users, and PUs' interference power constraints. The utility function of interest is nonconcave and the involved constraints are nonconvex, so this problem is hard to solve. Nevertheless, we propose a new iterative algorithm that finds local optima at the least. We use an inner approximation method to construct and solve a simple convex quadratic program of moderate dimension at each iteration of the proposed algorithm. Simulation results indicate that the proposed algorithm converges quickly and outperforms existing approaches.

关键词： Antenna selection cognitive radio nonconvex programming sum rate transmit beamforming

来源：评论

学校读者我要写书评

暂无评论

A branch and bound algorithm for nonconvex quadratic optimization with ball and linear constraints

引用

JOURNAL OF GLOBAL OPTIMIZATION 2017年第2期69卷 309-342页

作者： Beck, Amir Pan, Dror Technion Israel Inst Technol Fac Ind Engn & Management Haifa Israel

We suggest a branch and bound algorithm for solving continuous optimization problems where a (generally nonconvex) objective function is to be minimized under nonconvex inequality constraints which satisfy some specific solvability assumptions. The assumptions hold for some special cases of nonconvex quadratic optimization problems. We show how the algorithm can be applied to the problem of minimizing a nonconvex quadratic function under ball, out-of-ball and linear constraints. The main tool we utilize is the ability to solve in polynomial computation time the minimization of a general quadratic under one Euclidean sphere constraint, namely the so-called trust region subproblem, including the computation of all local minimizers of that problem. Application of the algorithm on sparse source localization problems is presented.

关键词： Quadratically constrained quadratic problems nonconvex programming Branch and bound Sparse source localization Trust region subproblem

来源：评论

学校读者我要写书评

暂无评论

Cooperative MIMO relay beamforming in overloaded DS/CDMA multicast networks

引用

IET COMMUNICATIONS 2017年第3期11卷 344-354页

作者： Mehrizi, Sajad Mahboobi, Behrad Islamic Azad Univ Sci & Res Branch Dept Engn Tehran Iran

A new beamforming scheme is proposed for multi-input multi-output (MIMO) non-regenerative relays in an overloaded synchronous direct sequence code division multiple access (DS-CDMA) network in which the number of users is larger than the processing gain. In this scheme, several transmitters multicast their data to their groups of receivers through MIMO relays and DS-CDMA technique is utilised to decrease the level of multiple access interference (MAI) at the relays and the receivers. At the relays, the data of transmitters are despread, beamformed and re-spread. The aim of the beamformer is to minimise the total relays transmission power subject to the signal to interference and noise ratio (SINR) constraints at the receivers. This optimisation problem is an indefinite quadratic (non-convex) programming. Semi-definite programming (SDP) and second-order cone programming (SOCP) are two existing methods to solve the problem. However, they, respectively, suffer from high computational complexity and performance degradation when the number of antennas or users increase. To effectively mitigate these deficiencies, we propose a novel DC (difference of two convex functions) programming method. Our simulation results demonstrate the computational advantage of the proposed DC programming over SDP, while a better performance over SOCP is achieved. Moreover, the superiority of the proposed MIMO-CDMA scheme over other multiplexing schemes is shown by several scenarios.

关键词： cooperative communication MIMO communication relay networks (telecommunication) array signal processing code division multiple access spread spectrum communication radiofrequency interference concave programming computational complexity cooperative MIMO relay beamforming overloaded synchronous DS-CDMA multicast networks multiinput multioutput nonregenerative relays direct sequence code division multiple access network multiple-access interference total relay transmission power minimization SINR constraint optimisation problem indefinite quadratic programming nonconvex programming computational complexity antenna number DC programming method difference-of-two convex functions SDP SOCP MIMO-CDMA scheme

来源：评论

学校读者我要写书评

暂无评论

An Out Space Accelerating Algorithm for Generalized Affine Multiplicative Programs Problem

引用

JOURNAL OF CONTROL SCIENCE AND ENGINEERING 2017年第6-14期2017卷 1-7页

作者： Cai, Lei Tang, Shuai Yin, Jingben Hou, Zhisong Jiao, Hongwei Henan Inst Sci & Technol Sch Informat Engn Xinxiang 453003 Peoples R China Jiyuan Vocat & Tech Coll Jiyuan 459000 Peoples R China Henan Inst Sci & Technol Sch Math Sci Xinxiang 453003 Peoples R China

This paper presents an out space branch-and-bound algorithm for solving generalized affine multiplicative programs problem. Firstly, by introducing new variables and constraints, we transform the original problem into an equivalent nonconvex programs problem. Secondly, by utilizing new linear relaxation technique, we establish the linear relaxation programs problem of the equivalent problem. Thirdly, based on the out space partition and the linear relaxation programs problem, we construct an out space branch-and-bound algorithm. Fourthly, to improve the computational efficiency of the algorithm, an out space reduction operation is employed as an accelerating device for deleting a large part of the investigated out space region. Finally, the global convergence of the algorithm is proved, and numerical results demonstrate the feasibility and effectiveness of the proposed algorithm.

关键词： nonconvex programming ACCELERATION (Mechanics) COMPUTER algorithms PROBLEM solving COMPUTATIONAL complexity STOCHASTIC convergence

来源：评论

学校读者我要写书评

暂无评论

A New Modified Three-Term Conjugate Gradient Method with Sufficient Descent Property and Its Global Convergence

引用

JOURNAL OF MATHEMATICS 2017年第1期2017卷 1-12页

作者： Baluch, Bakhtawar Salleh, Zabidin Alhawarat, Ahmad Roslan, U. A. M. Univ Malaysia Terengganu Sch Informat & Appl Math Kuala Nerus 21030 Terengganu Malaysia Al Isra Univ Dept Math Coll Sci Amman Jordan

A new modified three-term conjugate gradient (CG) method is shown for solving the large scale optimization problems. The idea relates to the famous Polak-Ribiere-Polyak (PRP) formula. As the numerator of PRP plays a vital role in numerical result and not having the jamming issue, PRP method is not globally convergent. So, for the new three-term CG method, the idea is to use the PRP numerator and combine it with any good CG formula's denominator that performs well. The new modification of three-term CG method possesses the sufficient descent condition independent of any line search. The novelty is that by using the Wolfe Powell line search the new modification possesses global convergence properties with convex and nonconvex functions. Numerical computation with the Wolfe Powell line search by using the standard test function of optimization shows the efficiency and robustness of the new modification.

关键词： CONJUGATE gradient methods STOCHASTIC convergence MATHEMATICAL optimization NONLINEAR theories CONVEX programming nonconvex programming

来源：评论

学校读者我要写书评

暂无评论

A variational principle for nonpotential perturbations of gradient flows of nonconvex energies

引用

JOURNAL OF DIFFERENTIAL EQUATIONS 2017年第6期262卷 3737-3758页

作者： Melchionna, Stefano Univ Vienna Fac Math Oskar Morgenstern Pl 1 A-1090 Vienna Austria

We investigate a variational approach to nonpotential perturbations of gradient flows of nonconvex energies in Hilbert spaces. We prove existence of solutions to elliptic-in-time regularizations of gradient flows by combining the minimization of a parameter-dependent functional over entire trajectories and a fixed-point argument. These regularized solutions converge up to subsequences to solutions of the gradient flow as the regularization parameter goes to zero. Applications of the abstract theory to nonlinear reaction diffusion systems are presented. (C) 2016 Elsevier Inc. All rights reserved.

关键词： VARIATIONAL principles PERTURBATION (Mathematics) REGULARIZATION (Mathematics) ELLIPTIC differential equations HILBERT space nonconvex programming

来源：评论

学校读者我要写书评

暂无评论

An efficient beamforming design for multipair full- duplex relaying systems

引用

ICT EXPRESS 2017年第1期3卷 9-13页

作者： Kim, Hyeon Min Van-Dinh Nguyen Shin, Oh-Soon Soongsil Univ Dept ICMC Convergence Technol Seoul 06978 South Korea Soongsil Univ Sch Elect Engn Seoul 06978 South Korea

We consider a decode-and-forward full-duplex relaying system for multiple pairs of users. Our objective is to maximize the minimum achievable rate for all user pairs under the transmit power constraints. We propose an iterative algorithm to solve the nonconvex max-min problem. In particular, the original problem is converted into successive convex programs by using an inner approximation method such that each iteration involves only a simple convex quadratic program. We show that the proposed algorithm improves achievement of the objective iteratively while guaranteeing convergence. Simulation results demonstrate that the proposed algorithm provides higher rates than both half-duplex and full-duplex relaying based on zero-forcing do. (C) 2017 The Korean Institute of Communications Information Sciences. Publishing Services by Elsevier B. V. This is an open access article under the CC BY-NC-ND license.

关键词： Full-duplex relaying Multipair relaying nonconvex programming Self-interference Transmit beamforming

来源：评论

学校读者我要写书评

暂无评论

Research on Mechanical Fault Diagnosis Scheme Based on Improved Wavelet Total Variation Denoising

引用

SHOCK AND VIBRATION 2016年第1期2016卷 1-10页

作者： He, Wentao Yi, Cancan Li, Yourong Xiao, Han Wuhan Univ Sci & Technol Sch Mech Engn Wuhan 430081 Peoples R China

Wavelet analysis is a powerful tool for signal processing and mechanical equipment fault diagnosis due to the advantages of multiresolution analysis and excellent local characteristics in time-frequency domain. Wavelet total variation (WATV) was recently developed based on the traditional wavelet analysis method, which combines the advantages of wavelet-domain sparsity and total variation (TV) regularization. In order to guarantee the sparsity and the convexity of the total objective function, nonconvex penalty function is chosen as a new wavelet penalty function in WATV. The actual noise reduction effect of WATV method largely depends on the estimation of the noise signal variance. In this paper, an improved wavelet total variation (IWATV) denoising method was introduced. The local variance analysis on wavelet coefficients obtained from the wavelet decomposition of noisy signals is employed to estimate the noise variance so as to provide a scientific evaluation index. Through the analysis of the numerical simulation signal and real-word failure data, the results demonstrated that the IWATV method has obvious advantages over the traditional wavelet threshold denoising and total variation denoising method in the mechanical fault diagnose.

关键词： FAULT diagnosis (Chemical engineering) WAVELETS (Mathematics) SIGNAL denoising MULTIRESOLUTION time-domain method nonconvex programming

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：