检索结果-南通市图书馆

Robust capacity maximization transceiver design for MIMO OFDM 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

Science China(Information Sciences) 2016年第6期59卷 119-129页

作者： Shaozhen GUO chengwen xing Zesong FEI Dan LI School of Information and Electronics Beijing Institute of Technology

In this paper, we investigated capacity maximization problem for Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing systems with imperfect channel state information(CSI). To the best of our knowledge, the considered problem is still an open problem. However, the transceiver designs for MIMO OFDM systems have been extensively studied. It seems nobody gives closed-form solutions for resource allocation for MIMO OFDM systems with statistical channel estimation errors up to date. In our work, based on practical channel estimation algorithm, the channel estimation errors are first derived and then the robust resource allocation problem has been formulated. The structure of the optimal robust precoder is first derived,based on which the optimization problem will be simplified significantly. Furthermore, based on the Lagrangian dual method, a robust power allocation algorithm is proposed. The proposed power allocation can be considered as a variant of water-filling solution named cluster water-filling solution. Finally, simulation results show that our proposed robust design outperforms the non-robust design in terms of channel capacity.

关键词： MIMO-OFDM capacity maximization water-filling channel uncertainty robust design

Distributed Resource Allocation in Ultra-Dense Networks via Belief Propagation

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 2015年第11期12卷 79-91页

作者： CHEN Siyi xing chengwen FEI Zesong Beijing Institute of Technology

Ultra-dense networking is widely accepted as a promising enabling technology to realize high power and spectrum efficient communications in future 5G communication systems. Although joint resource allocation schemes promise huge performance improvement at the cost of cooperation among base stations,the large numbers of user equipment and base station make jointly optimizing the available resource very challenging and even prohibitive. How to decompose the resource allocation problem is a critical issue. In this paper,we exploit factor graphs to design a distributed resource allocation algorithm for ultra dense networks,which consists of power allocation,subcarrier allocation and cell association. The proposed factor graph based distributed algorithm can decompose the joint optimization problem of resource allocation into a series of low complexity subproblems with much lower dimensionality,and the original optimization problem can be efficiently solved via solving these subproblems iteratively. In addition,based on the proposed algorithm the amounts of exchanging information overhead between the resulting subprob-lems are also reduced. The proposed distributed algorithm can be understood as solving largely dimensional optimization problem in a soft manner,which is much preferred in practical scenarios. Finally,the performance of the proposed low complexity distributed algorithm is evaluated by several numerical results.

关键词： resource allocation distributed optimization belief propagation(BP) ultradense network

Cooperative beamforming design for physical-layer security of multi-hop MIMO communications

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2016年第6期59卷 153-166页

作者： Shiqi GONG chengwen xing Zesong FEI Jingming KUANG School of Information and Electronics Beijing Institute of Technology

The security issue is critically important for wireless communications, especially for multi-hop communications. In this paper, we propose a cooperative secrecy beamforming scheme for a multi-hop MIMO communication network, in which there is a single-antenna source, multiple multi-antenna relays and a singleantenna destination. Moreover, two types of eavesdroppers exist in the network, one of which has known channel state information(CSI), while the other not. To achieve security communications, in our work null-space beamforming and artificial noise beamforming are jointly optimized to improve the secrecy rate of the multi-hop network. In nature, the joint optimization is nonconvex and challenging. Exploiting its structure, the considered optimization problem is decoupled into a series of subproblems that can be efficiently solved based on convex optimization theory. Finally, some numerical experiment results are provided to assess the performance of the proposed secrecy beamforming design.

关键词： MIMO physical layer security multi-hop network null-space beamforming artificial noise

Performance analysis for uplink massive MIMO systems with a large and random number of UEs

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) 2016年第2期59卷 163-171页

作者： Ang YANG chengwen xing Zesong FEI Jingming KUANG School of Information and Electronics Beijing Institute of Technology

In this paper, we analyze the ergodic achievable rate of an uplink massive multi-user multipleinput multiple-output(MIMO) system with a large and Poisson distributed number of users. In the considered scenario, multiple user equipments(UEs) transmit their information to a base station equipped with a very large number of antennas. New asymptotic expressions for the ergodic achievable rate for large and deterministic number of users are derived for both maximum ratio combining(MRC) detector and zero-forcing(ZF) detector,as well as the ergodic achievable rate for large and random number of users. Simulation results assess the accuracy of these analytical expressions. It is shown that compared with the MRC detector, ZF detector can achieve much higher spectrum efficiency. Also, the results provide a meaningful fact that with different settings the randomness of the number of users will result in different extents of impact on the performance of massive MIMO.

关键词： massive MIMO large numbers of UEs maximum ratio combining detector zero-forcing detector ergodic achievable rates

Resource Allocation for Physical Layer Security in Heterogeneous Network with Hidden Eavesdropper

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3期13卷 82-95页

作者： GONG Shiqi xing chengwen FEI Zesong KUANG Jingming School of Information and Electronics Beijing Institute of Technology

The tremendous performance gain of heterogeneous networks(Het Nets) is at the cost of complicated resource allocation. Considering information security, the resource allocation for Het Nets becomes much more challenging and this is the focus of this paper. In this paper, the eavesdropper is hidden from the macro base stations. To relax the unpractical assumption on the channel state information on eavesdropper, a localization based algorithm is first given. Then a joint resource allocation algorithm is proposed in our work, which simultaneously considers physical layer security, cross-tier interference and joint optimization of power and subcarriers under fairness requirements. It is revealed in our work that the considered optimization problem can be efficiently solved relying on convex optimization theory and the Lagrangian dual decomposition method is exploited to solve the considered problem effectively. Moreover, in each iteration the closed-form optimal resource allocation solutions can be obtained based on the Karush-Kuhn-Tucker(KKT) conditions. Finally, the simulation results are given to show the performance advantages of the proposed algorithm.

关键词： resource allocation physical layer security heterogeneous networks RSS-based location estimation lagrangian dual decomposition

Transceiver designs with matrix-version water-filling architecture under mixed power constraints

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2016年第10期59卷 169-180页

作者： chengwen xing Zesong FEI Yiqing ZHOU Zhengang PAN Hualei WANG School of Information and Electronics Beijing Institute of Technology Wireless Communication Research Center Institute of Computing TechnologyChinese Academy of Sciences China Mobile Research Institute

In this paper, we investigate the multiple-input multiple-output(MIMO) transceiver design under an interesting power model named mixed power constraints. In the considered power model, several antenna subsets are constrained by sum power constraints while the other antennas are subject to per-antenna power constraints. This kind of transceiver designs includes both the transceiver designs under sum power constraint and per-antenna power constraint as its special cases. This kind of designs is of critical importance for distributed antenna systems(DASs) with heterogeneous remote radio heads(RRHs) such as cloud radio access networks(C-RANs). In our work, we try to solve the optimization problem in an analytical way instead of using some famous software packages e.g., CVX or Se Du Mi. In our work, to strike tradeoffs between performance and complexity, both iterative and non-iterative solutions are proposed. Interestingly the non-iterative solution can be interpreted as a matrix-version water-filling solution extended from the well-known and extensively studied vector version. Finally, simulation results demonstrate the accuracy of our theoretical results.

关键词： convex optimization MIMO matrix-version water-filling transceiver designs mix power constraints

Energy-Efficient Transceiver Design for Multi-Pair Two-Way Relay 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 2015年第9期12卷 133-140页

作者： Fei Zesong Li Na xing chengwen Gong Shiqi School of Information and Electronics Beijing Institute of Technology

In this paper, we focus on energy-efficient transceiver and relay beamforming design for multi-pair two-way relay system. The multi-antenna users and the multi-antenna relay are considered in this work. Different from the existing works, the proposed algorithm is energy-efficient which is more applicable to the future green network. It considers both the sum-MSE problem and the power consumption problem for the users under the relay power constraint. Based on the optimal condition decomposition(OCD) method, the energy-efficient precoders at the users can be designed separately with limited information exchanged. The proposed relay beamforming algorithm is based on the alternative direction method of multipliers(ADMM) which has simpler iterative solution and enjoys good convergence. Simulation results demonstrate the performance of the proposed algorithms in terms of power consumption and MSE performance.

关键词： two-way relay energy efficient optimal condition decomposition alternative direction method of multipliers

Distributed cooperative localization based on Gaussian message passing on factor graph in wireless networks

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2015年第4期58卷 78-92页

作者： WU Nan LI Bin WANG Hua xing chengwen KUANG JingMing School of Information and Electronics Beijing Institute of Technology

In conventional localization, agents may not be able to reach sufficient number of anchors to obtain unambiguous locations, especially in sparse networks. Cooperative localization is a promising solution in that harsh environment, which enables the agents to cooperate with each other by exchanging location information and performing range measurements. In this paper, a distributed cooperative localization method based on factor graph is proposed in wireless networks. Gaussian parametric messages are used to represent the messages passed on factor graph. However, because of the nonlinear observation model, no closed-form solutions can be obtained. To solve this problem, the Taylor expansion is used to approximate the nonlinear terms in message updating, which leads to the Gaussian message passing on factor graph. Accordingly, only two parameters of the Gaussian distribution have to be transmitted and the communication overhead for localization can be significantly reduced. The two proposed algorithms for the application with accurate and inaccurate anchors,respectively, are evaluated by Monte Carlo simulations and compared with the SPAWN and maximum likelihood(ML) estimator. The results show that the proposed algorithms can perform very close to SPAWN with much lower computational complexity, and it outperforms the ML estimator significantly.

关键词： wireless networks cooperative localization factor graph Gaussian message passing

FULL-DUPLEX WIRELESS COMMUNICATIONS

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11期13卷 I0001-I0003页

作者： lajos hanzo chengwen xing zhongshan zhang yiqing zhou eurasip the ieee vts school of information and electronics beijing institute of technology school of computer and communication engineering in the university of science and technology beijing (ustb) the wireless communication research center institute of computing technologychinese academy of sciences the ieee transactions on vehicular technology the ieee journal on selected areas in communications wireless communications and mobile computing the transactions on emerging telecommunications technologies the journal of computer science and technology

Just as Dickens wrote,it is the best of times,it is the worst of *** increasing traffic demands will bring us into the era of *** of unprecedented or even unanticipated fancy wireless applications will definitely change our *** the beautiful visions promised by 5G,meanwhile the wireless engineers are faced with unprecedented challenges and pressures for realizing much higher spectrum efficiency and

关键词：无线通信交通需求无线应用