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LMMSE-based SAGE channel estimation and data detection joint algorithm for MIMO-OFDM system

High Technology Letters 2012年第2期18卷 195-201页

作者：申京 Wu Muqing Laboratory of Network System Architecture and Convergence Beijing University of Posts and TelecommunicationsBeijing 100876P.R.China

A new channel estimation and data detection joint algorithm is proposed for multi-input multi-output （MIMO） - orthogonal frequency division multiplexing （OFDM） system using linear minimum mean square error （LMMSE）- based space-alternating generalized expectation-maximization （SAGE） algorithm. In the proposed algorithm, every sub-frame of the MIMO-OFDM system is divided into some OFDM sub-blocks and the LMMSE-based SAGE algorithm in each sub-block is used. At the head of each sub-flame, we insert training symbols which are used in the initial estimation at the beginning. Channel estimation of the previous sub-block is applied to the initial estimation in the current sub-block by the maximum-likelihood （ML） detection to update channel estimatjon and data detection by iteration until converge. Then all the sub-blocks can be finished in turn. Simulation results show that the proposed algorithm can improve the bit error rate （BER） performance.

关键词： multi-input multi-output (MIMO) orthogonal frequency division multiplexing (OFDM) linear minimum mean square error (LMMSE) space-alternating generalized expectation-maximization (SAGE) iteration channel estimation data detection joint algorithm.

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Intelligent UAV Based Energy Supply for 6G Wireless Powered IoT networks

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China Communications 2024年第9期21卷 321-337页

作者： Miao Jiansong Chen Haoqiang Wang Pengjie Li Hairui Zhao Yan Mu Junsheng Yan Shi School of Information and Communication Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and TelecommunicationsBeijing 100876China

In this paper,we develop a 6G wireless powered Internet of Things(IoT)system assisted by unmanned aerial vehicles(UAVs)to intelligently supply energy and collect data at the same *** our dual-UAV scheme,UAV-E,with a constant power supply,transmits energy to charge the IoT devices on the ground,whereas UAV-B serves the IoT devices by data collection as a base *** this framework,the system's energy efficiency is maximized,which we define as a ratio of the sum rate of IoT devices to the energy consumption of two UAVs during a fixed working *** the constraints of duration,transmit power,energy,and mobility,a difficult non-convex issue is presented by optimizing the trajectory,time duration allocation,and uplink transmit power of *** tackle the non-convex fractional optimization issue,we deconstruct it into three subproblems and we solve each of them iteratively using the descent method in conjunction with sequential convex approximation(SCA)approaches and the Dinkelbach *** simulation findings indicate that the suggested cooperative design has the potential to greatly increase the energy efficiency of the 6G intelligent UAV-assisted wireless powered IoT system when compared to previous benchmark systems.

关键词： 6G wireless powered network energy efficiency IoT intelligent network UAV communication

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Evolved data scheduling scheme based on layered P2P streaming in mobile network

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The Journal of China Universities of Posts and Telecommunications 2012年第3期19卷 60-67页

作者： XIA Hai-lun WANG Ning ZENG Zhi-min School of Information and Communication Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China/Beijing Key Laboratory of Network System Architecture and ConvergenceBeijing University of Posts and TelecommunicationsBeijing 100876China

To relieve the negative effect brought by the intricate wireless network environment and unstable user behavior in layered mobile peer-to peer（P2P） streaming service, an evolved layered P2P （E-LP2P） data scheduling scheme in the process of service delivery is introduced in this paper. The data in base layer is scheduled according to its importance in streaming play to guarantee the basic play of streaming. The data in enhancement layer is scheduled according to the characters of streaming data, including its position and amount in server peer set in a multiple tied way towards the data in enhancement layer. To cope with the layer jitter caused by the fluctuation of bandwidth, jitter prevent mechanism is used to adjust the highest layer dynamically during the process of data scheduling. Simulation results show that the E-LP2P can provide good quality of service（QoS） performance in terms of throughput, layer delivery ratio, server load and useless packet ratio.

关键词： layered streaming P2P mobile network data scheduling

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AP LOAD BALANCE BASED HANDOVER IN SOFTWARE DEFINED WiFi systemS 5

AP LOAD BALANCE BASED HANDOVER IN SOFTWARE DEFINED WiFi SYST...

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2016 5th IEEE International Conference on network Infrastructure and Digital Content(IC-NIDC 2016)

作者： Nahida Kiran Yin Changchuan Zaid Akram Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications

ISBN: (纸本)9781509012473

In existing wireless systems it's hard for an operator to change the network strategy under heavy load due to its proprietary and inflexible hardware based *** paper explores the concept of software defined networking(SDN) in wireless *** access point(AP) load balance based handover scheme in SDN WiFi systems is proposed for overlapping wireless local area network cells to take efficient handover based on AP *** implemented the proposed load balancing handover scheme in Mininet-WiFi emulator which could handle the APs from a centralized controller and help the test client determine how and when to connect with the right AP and take efficient handover based on AP *** interface is added with the station,client's traffic is tested at different positions and improved throughput for mobile clients is *** results show that total network throughput is enhanced after a successful handover.

关键词： Software defined networking Wireless networks Mini-net Mininet-WiFi

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A Novel MIMO Channel Model for High Speed Railway system

A Novel MIMO Channel Model for High Speed Railway System

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2012 IEEE 14th International Conference on Communication Technology

作者： Zheng Qianqian Xu Chunxiu Wu Muqing Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications

ISBN: (纸本)9781467321006

This paper focuses on the Geometry based Stochastic Channel Model (GSCM) and its application in high speed railway (HSR) multiple-input multiple-output (MIMO) *** probability distribution functions (PDFs) of scatterers are studied and simulation results show that scatterers in Gaussian distribution make the best approximation to the realistic power delay profile (PDP) and power azimuth spectra (PAS).Additionally,the impacts of different scattering area shapes on the PDP and PAS in high speed railway scenario are *** on the conclusions above and existing measurement data,a novel channel model is established with local and far scatterer clusters for high speed railway *** simulation results verify that our model is realistic.

关键词： Geometry Based Stochastic Channel Model (GSCM) power delay profile (PDP) power azimuth spectra (PAS) High Speed Railway(HSR) multiple-input multiple- output (MIMO)

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On-line learning algorithm for dynamic sensitivity control in IEEE 802. 11ax network

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The Journal of China Universities of Posts and Telecommunications 2018年第5期25卷 67-74页

作者： Li Qishan Hu Zhiqun Wen Xiangming Lu Zhaoming Qi Hang School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing Laboratory of Advanced Information Networks Beijing University of Posts and Telecommunications

The popularity of IEEE 802. 11 based wireless local area network（ WLAN） increased significantly in recent years and resulted in the dense deployment of WLANs. While densification can contribute to increasing coverage,it could also lead to increasing interference and cannot insure high spatial reuse due to the current physical carrier sensing of IEEE 802. 11. To tackle these challenges,the dynamic sensitivity control（ DSC） is considered in IEEE802. 11 ax,which dynamically selects the appropriate carrier sensing threshold（ CST） to improve spectrum efficiency and enhance spatial reuse in densely deployed network. A dynamic Q-learning based CST selection method is proposed to enable a network to select the optimal CST according to the channel condition. Simulation results show that the proposed scheme provides 40% aggregate throughput gain of a dense network when compared with legacy IEEE 802. 11.

关键词： IEEE 802. llax reinforcement learning dynamic sensitivity control dense network

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A 3-D Polarization Quadrature Amplitude Modulation Method and Constellation Mapping

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China Communications 2015年第10期12卷 16-26页

作者： SUN Xuehong ZHANG Haiying ZENG Zhimin GUO Caili Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication EngineeringBeijing University of Posts and Telecommunications Key Laboratory of Intelligent Sensing for Desert Information School of Physics Electrical EngineeringNingxia University

As a new three-dimensional(3-D)modulation,Polarization Quadrature Amplitude Modulation(PQAM) can be regarded as the combination of Pulse amplitude modulation(PAM) and Quadrature Amplitude Modulation(QAM) *** can better improve the digital communication efficiency and reduce the Symbol error rate(SER) of the system than one-dimensional or two-dimensional modulation *** to design a feasible constellation is the most concerned problem of PQAM *** paper first studies the relationship between the SER theoretical value of PQAM and the distribution of M and N,proposes a new M,N allocation ***,a new and straightforward design method of constructing higher-level 3-D signal constellations,which can be matched with the PQAM,and the constellation can divided into three different structures according to the ary for ***,the simulation results show that:in PQAM system,the modulation scheme and the constellation mapping scheme are proposed in this paper which can effectively reduce the system SER and improve the anti-noise performance of the system.

关键词： polarization quadrature amplitude modulation minimum euclidean distance symbol error probability 3-D constellation

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QoS-priority based load balancing algorithm for LTE systems with mixed users

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The Journal of China Universities of Posts and Telecommunications 2015年第3期22卷 9-17页

作者： Chuai Gang Meng Fanfan Sun Li School of Information and Communication Engineering Beijing University of Posts and Telecommunications Key Laboratory of Universal Wireless Communications Ministry of EducationBeijing University of Posts and Telecommunications Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications

Focusing on the load balancing problem among multi-cells in long term evolution （LTE） networks with mixed users, a new multi-objective optimization modeling strategy, which integrates the guaranteed bit rate （GBR） and the best effort （BE） users, was proposed. In consideration of quality of service （QoS） priorities of different users, a decomposition method was presented to solve the original model. Derivations such as applying Lagrange multiplier method, sub-optimal solutions for mixed users were deduced. Based on derived solutions, including resource allocation schemes, a practical multi-objective load balancing algorithm jointly dealing with mixed users was given. Simulation shows a significant improvement of GBR users＇ satisfaction level and BE users＇ throughput in LTE networks by using the proposed algorithm.

关键词： long term evolution system quality of service mixed users multi-objective optimization load balancing resource allocation

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Modeling deterministic echo state network with loop reservoir

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Journal of Zhejiang University-Science C(Computers and Electronics) 2012年第9期13卷 689-701页

作者： Xiao-chuan SUN Hong-yan CUI Ren-ping LIU Jian-ya CHEN Yun-jie LIU Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing 100876China ICT Centre Commonwealth Scientific and lndustrial Research OrganizationSydney 1710Austraiia

Echo state network (ESN), which efficiently models nonlinear dynamic systems, has been proposed as a special form of recurrent neural network. However, most of the proposed ESNs consist of complex reservoir structures, leading to excessive computational cost. Recently, minimum complexity ESNs were proposed and proved to exhibit high performance and low computational cost. In this paper, we propose a simple deterministic ESN with a loop reservoir, i.e., an ESN with an adjacent-feedback loop reservoir. The novel reservoir is constructed by introducing regular adjacent feedback based on the simplest loop reservoir. Only a single free parameter is tuned, which considerably simplifies the ESN construction. The combination of a simplified reservoir and fewer free parameters provides superior prediction performance. In the benchmark datasets and real-world tasks, our scheme obtains higher prediction accuracy with relatively low complexity, compared to the classic ESN and the minimum complexity ESN. Furthermore, we prove that all the linear ESNs with the simplest loop reservoir possess the same memory capacity, arbitrarily converging to the optimal value.

关键词： Echo state networks Loop reservoir structure Memory capacity

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Nash bargaining solution based multi-cell and multi-user interference alignment scheme for cellular networks

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The Journal of China Universities of Posts and Telecommunications 2014年第4期21卷 1-7,14页

作者： NIU Qin ZENG Zhi-min ZHANG Tian-kui GAO Qiu-bin SUN Shao-hui School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications State Key Laboratory of Wireless Mobile Communications China Academy of Telecommunication Technology

In wireless cellular networks, the interference alignment （IA） is a promising technique for interference management. A new IA scheme for downlink cellular network with multi-cell and multi-user was proposed, in the proposed scheme, the interference in the networks is divided into inter-cell interference （ICI） among cells and inter-user interference （IUI） in each cell. The ICI is aligned onto a multi-dimensional subspace by multiplying the ICI alignment precoding matrix which is designed by the singular value decomposition （SVD） scheme at the base station （BS） side. The aligned ICI is eliminated by timing the interference suppression matrix which is designed by zero-forcing （ZF） scheme at the user equipment （UE） side. Meanwhile, the IUI is aligned by multiplying the IUI alignment precoding matrix which is designed based on Nash bargaining solution （NBS） in game theory. The NBS is solved by the particle swarm optimization （PSO） method. Simulations show that, compared with the traditional ZF IA scheme, the proposed scheme can obtain higher data rate and guarantee the data rate fairness of UEs with little additional complexity.

关键词： cellular network interference alignment Nash bargaining solution data rate fairness particle swarm optimization

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