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Turbo equalization based on joint Gaussian,SIC-MMSE and LMMSE for nonlinear satellite channels

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Science China(Information Sciences) 2018年第4期61卷 151-163页

作者： Zheren LONG Hua WANG Nan WU jingming kuang School of Information and Electronics Beijing Institute of Technology

The nonlinear distortion of wideband signal due to the filtering and efficiently operated high power amplifiers limits the performance of satellite communications. Volterra series can be used to describe the nonlinear satellite channels effectively. Most existing equalizers simply ignore the nonlinear terms or treat all the nonlinear combinations of symbols as interference. In this study, by properly exploiting information from nonlinear terms, we propose three turbo equalizers for nonlinear satellite channels, namely, joint Gaussian(JG), soft interference cancellation-minimum mean square error(SIC-MMSE) and linear minimum mean square error(LMMSE) equalizers. In JG and SIC-MMSE-based equalizers, both the linear and nonlinear terms that contain the symbol of interest are considered as desired signals. Accordingly, the required statistics are calculated based on the a priori probabilities of coded bits from output of channel *** LMMSE-based equalizer, we propose to calculate the extrinsic information from output of equalizer by excluding the prior information in both the linear and nonlinear terms. Simulation results demonstrate that the proposed equalizers significantly outperform the method which ignores the presence of nonlinear interferences. Moreover, the nonlinear terms that contain the symbol of interest can be exploited to further improve the performance of turbo equalization.

关键词： nonlinear satellite channel turbo equalization joint Gaussian soft interference cancellationminimum mean square error(SIC-MMSE) linear minimum mean square error(LMMSE)

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

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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

A QoE-based jointly subcarrier and power allocation for multiuser multiservice networks

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Science China Earth Sciences 2016年第12期59卷 34-46页

作者： Niwei WANG Shiqi GONG Zesong FEI jingming kuang School of Information and Electronics Beijing Institute of Technology

Quality of experience(QoE) is widely applied to reflect user's satisfaction of the network service,which exactly conforms to the user-centric concept in 5G. In this paper, we propose a QoE-based subcarrier and power allocation algorithm for the downlink transmission of a multiuser multiservice system. For the subcarrier allocation algorithm, the rate proportional fairness factor is defined to ensure the fairness between users. Based on different QoE models of three services, i.e., file down(FD), video streaming and voice over internet protocol(VOIP), a multi-objective optimization method is exploited to allocate the power resource by minimizing the total power consumption and maximizing the mean opinion score(MOS) value of users simultaneously. Simulation results indicate that the proposed algorithm has less power consumption and higher QoE performance than the traditional proportional fairness(PF) algorithm. In addition, the proposed algorithm can achieve nearly the same fairness performance as the PF algorithm. Moreover, when the number of subcarriers becomes larger, the power assumption will be less but with little influence on both the QoE and fairness performances.

关键词： QoE QoS MOS multiservice multi-objective optimization

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

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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

Parametric message passing-based relative navigation in joint tactical information distribution system

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Journal of Systems Engineering and Electronics 2016年第1期27卷 81-89页

作者： Nan Wu Bin Li Hua Wang Liang Hou jingming kuang School of Information and Electronics Beijing Institute of Technology

Relative navigation is a key feature in the joint tactical information distribution system（JTIDS）.A parametric message passing algorithm based on factor graph is proposed to perform relative navigation in *** of all,the joint posterior distribution of all the terminals＇ positions is represented by factor *** of the nonlinearity between the positions and time-of-arrival（TOA） measurement,messages cannot be obtained in closed forms by directly using the sum-product algorithm on factor *** this end,the Euclidean norm is approximated by Taylor ***,all the messages on the factor graph can be derived in Gaussian forms,which enables the terminals to transmit means and ***,the impact of major error sources on the navigation performance are evaluated by Monte Carlo simulations,e.g.,range measurement noise,priors of position uncertainty and velocity *** show that the proposed algorithm outperforms the extended Kalman filter and cooperative extended Kalman filter in both static and mobile scenarios of the JTIDS.

关键词： joint tactical information distribution system(JTIDS) relative navigation parametric message passing factor graph.

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

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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

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

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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

Enhanced frameless slotted ALOHA protocol with Markov chains analysis

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Science China(Information Sciences) 2018年第10期61卷 187-197页

作者： Dai JIA Zesong FEI Ming XIAO Congzhe CAO jingming kuang School of Information and Electronics Beijing Institute of Technology School of Electrical Engineering Royal Institute of Technology Department of Electrical and Computer Engineering University of Alberta

In this paper, we propose a novel approach to enhance the performance of frameless slotted ALOHA(SA) protocol. We employ signature codes to help the receiver identify the packets contained in collisions, and use successive interference cancellation(SIC) for packet recovery. We model the proposed scheme as a two-state Markov model represented by a uni-partite graph. We evaluate the throughput,expected delay and average memory size of the proposed scheme, and optimize the proposed scheme to maximize the throughput. We show that the theoretical analysis matches well with simulation *** throughput and expected delay of the proposed protocol outperform the conventional slotted ALOHA protocol significantly.

关键词： slotted ALOHA SIC Markov chain uni-partite graph throughput delay

A New Thought of Channel Protection——Adaptive Multi-mode Error-correction coding

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A New Thought of Channel Protection——Adaptive Multi-mode E...