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spectrum efficiency Maximization for Cooperative Power Beacon-Enabled Wireless Powered Communication Networks

China Communications 2021年第12期18卷 230-251页

作者： Wenjun Xu Wei Chen Yongjian Fan Zhi Zhang Xinxin Shi Key Lab of Universal Wireless Communications Ministry of EducationBeijing University of Posts and TelecommunicationsBeijing 100876China Hebei Key Laboratory of Security and Protection Information Sensing and Processing Hebei University of EngineeringHandan 056038China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China Beijing Telecom Planning&Designing Institute Co. Ltd.Beijing 100048China

We consider a spectrum efficiency(SE)maximization problem for cooperative power beacon-enabled wireless powered communication networks(CPB-WPCNs),where each transmitter harvests en-ergy from multi-antenna power beacons(PBs)and transmits data to the corresponding *** data transmission,both orthogonal transmission,i.e.,the time splitting(TS)mode,and non-orthogonal trans-mission,i.e.,the interference channel(IC)mode,are *** to improve the system SE,the energy beamformers of PBs,the transmit power,and the transmit time duration of transmitters are jointly *** the TS mode,the original non-convex problem is transformed into a convex opti-mization problem by means of variable substitution and semidefinite relaxation(SDR).The rank-one na-ture of this SDR is proved,and then a Lagrange-dual based fast algorithm is proposed to obtain the opti-mal solution with much lower *** the IC mode,to conquer the strong non-convexity of the problem,a branch-reduce-and-bound(BRB)mono-tonic optimization algorithm is designed as a ***,a low-complexity distributed suc-cessive convex approximation(SCA)algorithm is ***,simulation results validate the perfor-mance of the proposed algorithms,achieving optimal-ity within only 1%∼2%computation time compared to the CVX solver in the TS mode and achieving 98%of the optimal performance in the IC mode.

关键词： spectrum efficiency power beacon WPCN time splitting interference channel wireless power transfer

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High spectrum efficiency channel encoding method

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The Journal of China Universities of Posts and Telecommunications 2009年第3期16卷 30-32,44页

作者： YANG Chun-ping LI Dao-ben School of Electrical and Electronic Engineering North China Electric Power University Beijing 102208 China School of Information Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

A novel high spectrum efficiency channel encoding method called overlapped code division multiplexing （OvCDM） is presented. It is a convolutional encoding method with code rate greater than 1. Compared with traditional coded modulation （CM） technologies, OvCDM emphasizes the constrain relation between encoded codes. It is actually a blind modulation. The simulation results in the additive white Gaussian noise （AWGN） channel indicate that OvCDM can significantly improve spectrum efficiency of mobile communications systems. Meanwhile, the proposed OvCDM can ensure high decoding performance.

关键词： spectrum efficiency convolutional encoding code rate AWGN OvCDM

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Resource Allocation in Multi-User Cellular Networks:A Transformer-Based Deep Reinforcement Learning Approach

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China Communications 2024年第5期21卷 77-96页

作者： Zhao Di Zheng Zhong Qin Pengfei Qin Hao Song Bin State Key Laboratory of Integrated Services Networks Xidian University710071China China Academy of Space Technology Beijing 100081China

To meet the communication services with diverse requirements,dynamic resource allocation has shown increasing *** this paper,we consider the multi-slot and multi-user resource allocation(MSMU-RA)in a downlink cellular scenario with the aim of maximizing system spectral efficiency while guaranteeing user *** first model the MSMURA problem as a dual-sequence decision-making process,and then solve it by a novel Transformerbased deep reinforcement learning(TDRL)***,the proposed TDRL approach can be achieved based on two aspects:1)To adapt to the dynamic wireless environment,the proximal policy optimization(PPO)algorithm is used to optimize the multi-slot RA strategy.2)To avoid co-channel interference,the Transformer-based PPO algorithm is presented to obtain the optimal multi-user RA scheme by exploring the mapping between user sequence and resource *** results show that:i)the proposed approach outperforms both the traditional and DRL methods in spectral efficiency and user fairness,ii)the proposed algorithm is superior to DRL approaches in terms of convergence speed and generalization performance.

关键词： dynamic resource allocation multi-user cellular network spectrum efficiency user fairness

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Hybrid inter-cell interference management for ultra-dense heterogeneous network in 5G

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Science China(Information Sciences) 2016年第8期59卷 180-192页

作者： Chen HUANG Qianbin CHEN Lun TANG Key Laboratory of Mobile Communication Technology School of Communication and Information EngineeringChongqing University of Posts and Telecommunications

The Ultra-dense Heterogeneous Network(Het Net), which consists of macro-cells and pico-cells, has been recognized as a key technique to improve network performance. However, the increasing number of pico-cells also causes severe interference including inter-cell interference and intra-cell interference. Therefore, interference management has become an important issue in ultra-dense Het Nets, and the traditional enhanced inter-cell interference coordination(e ICIC) scheme is no longer fit for the high density of small cells. In this paper, a hybrid interference management method based on dynamic e ICIC and coordinated multi-point transmission(Co MP) is proposed. Firstly, a virtual cell is established based on the characteristics of ultra dense Het ***, a novel joint dynamic e ICIC scheme combined with multi-user beamforming is deployed to eliminate the inter-cell interference, and improve the throughput of virtual cell significantly without sharp decrease of throughput of macro-cell. Furthermore, a virtual cell based joint transmission scheme is deployed with a power control algorithm, which can obviously increase the spectrum efficiency of virtual cell edge. Simulation results verify that the proposed scheme can achieve better spectrum efficiency both at macro-cell and virtual cell edges,and the network throughput is also improved.

关键词： interference management coordinated multi-point transmission ultra dense network almost blank subframe spectrum efficiency

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Cross-layer design for cooperative MIMO systems with relay selection and imperfect CSI

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Science China(Information Sciences) 2013年第2期56卷 129-138页

作者： YU XiangBin ZHOU TingTing RUI Yun YIN Xin CHEN Ming College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics National Mobile Communications Research Laboratory Southeast University Shanghai Advanced Research Institute Chinese Academic of Science

Based on imperfect channel state information (CSI) and relay selection, a cross-layer optimization scheme is developed for cooperative MIMO system, and the corresponding system performance is investigated in Rayleigh fading channel. By the theoretical analysis and mathematical manipulation, the average spectral efficiency (SE), packet error rate (PER) and packet loss rate (PLR) are derived. As a result, closed-form expressions of the average SE, PER and PLR are obtained, respectively. According to these, a cross-layer design (CLD) scheme subject to the average PER constraints is proposed to avoid the SE performance loss caused by the conventional instantaneous PER constraints. The scheme optimizes the adaptive thresholds by maximizing the average SE of the system, and an iteration method joint the Lagrange multiplier and Newton methods is presented to solve the above optimization problem. Simulation results verify the validity of the theoretical analysis. The results show that the proposed CLD scheme can improve the SE while target PLR is maintained. The CLD scheme under average PER constraints has higher SE than the conventional CLD scheme under instantaneous PER constraints.

关键词： cross-layer design relay selection cooperative MIMO imperfect CSI spectrum efficiency packet loss rate

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Cooperative communications with hierarchical modulation in downlink OFDMA based cellular networks

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Journal of Harbin Institute of Technology(New Series) 2011年第6期18卷 143-148页

作者：张海龙纪红李曦张琳 Key Lab of Universal Wireless Communications Ministry of EducationBeijing University of Posts and Telecommunications

Cooperative transmission is a promising way to improve system performance in orthogonal frequency division multiple access (OFDMA) based cellular *** paper proposes two heuristic cooperation schemes including relay selection and resource allocation using hierarchical modulation (HM) to fully exploit the radio resources in cellular networks where user equipments (UEs) relay for each *** relay selection procedure considers both the channel conditions and the energies left in relays to make the cooperative communications behave *** mitigate the spectrum efficiency loss due to the half-duplex mode,the bits of relayaided UE and its relay (which is also a UE) are transmitted simultaneously in one sub-channel using HM to improve the utilization efficiency of ***,time resources are used effectively with the adaptively changed proportion of the two sub-frames divided for relay *** results show that the proposed schemes can improve the spectrum efficiency compared with the traditional schemes.

关键词： cooperative communications hierarchical modulation half-duplex spectrum efficiency orthogonal frequency division multiple access (OFDMA)

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A novel adaptive spectrum forming filter:Application in cognitive ultra-wideband

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Science China(Information Sciences) 2010年第12期53卷 2584-2599页

作者： LI Bin ,ZHOU Zheng & ZOU WeiXia Key Lab of Universal Wireless Communications,MOE.Wireless Network Lab,Beijing University of Posts and Telecommunications,Beijing 100876,China Key Lab of Universal Wireless Communications MOE. Wireless Network Lab Beijing University of Posts and Telecommunications Beijing China

Ultra wideband impulse radio(UWB-IR) has important applications in high data rate communications,high precision positioning and penetrating target *** with cognitive radio(CR),UWB can also greatly alleviate the current spectrum ***,the existing UWB waveforms are faced with two *** spectrum utilization of UWB signal is rather low,which reduces the communication ***,it appears difficult for UWB-IR to avoid spectrum collision with other incumbent *** UWB will inevitably interfere other legal wireless *** by these considerations,we model the UWB waveform design into an interpolation *** on radial basis function neural network,a novel UWB pulse is presented in this *** UWB pulse is then realized though reasonable simplification on the already proposed theoretical *** designed UWB pulses can adaptively track the external spectral environment where UWB devices work and reconfigure its emission spectrum according to the state of primer users without any modification on *** frequency utilization is maximized when there is no active primary *** adequate spectrum avoidance has also been achieved without much spectrum utilization degradation within the non-primary *** and analysis show that our UWB-IR pulse is much superior to the other existing UWB signals in the frequency utilization,spectrum avoidance and in the transmission performance.

关键词： UWB-IR cognitive radio pulse design RBF network spectrum efficiency spectrum avoidance

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Bifocal-Lens Converging Based OAM Wireless Communications

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Journal of Communications and Information Networks 2019年第2期4卷 89-100页

作者： Shanghua Gao Wenchi Cheng Hailin Zhang State Key Laboratory of Integrated Services Networks Xidian UniversityXi’an 710071China

Orbital angular momentum(OAM)based radio vortex wireless communications have received much attention recently because it can significantly increase the spectrum *** uniform circular array(UCA)is a simple antenna structure for high spectrum efficiency radio vortex wireless ***-ever,the OAM based electromagnetic waves are vortically hollow and divergent,which may result in the signal ***,the divergence of corresponding OAM based electromagnetic wave increases as the order of OAM-mode ***,it is difficult to use high-order OAM-mode,because the corresponding received signal-to-noise ratio(SNR)is very *** overcome the difficulty of high-order OAM modes transmission,in this paper we propose a lens antenna based electromagnetic waves converging scheme,which maintains the angular identification of multiple OAM-modes for radio vortex wireless *** further develop a bifocal lens antenna to not only converge the electromagnetic wave,but also compensate the SNR loss on traditional electromagnetic *** results show that the proposed bifocal lens can converge the OAM waves into cylinder-like beams,providing an efficient way to in-crease the spectrum efficiency of wireless communications.

关键词： OAM bifocal lens antenna convergence UCA wireless communications spectrum efficiency

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A Novel Multi-Modal OAM Vortex Electromagnetic Wave Microstrip Array Antenna

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Journal of Communications and Information Networks 2019年第4期4卷 95-106页

作者： Xuehong Sun Jianfeng Shao Boya Dan Qiang Li School of Physics and Electronic-Electrical Engineering Ningxia UniversityNingxia 750021China

In this paper,we combine the circular polarization technology and orbital angular momentum(OAM)into the array antenna design for the first time,achieve free switch of the different topological charges in the array by using high-speed radio frequency(RF)switch *** arrange microstrip patch antenna elements equidistantly along the circumference to form eight elements multi-modal OAM vortex electromagnetic wave microstrip array *** can generate elec-tromagnetic waves with dual characteristics of circular polarization and multi-modal vortex OAM(where OAM mode values are l=0,l=±1,l=±2,l=±3).Through simulation,we find mutual coupling between the radiating elements is small relatively,and increasing the number of array elements can not only improve the beam quality,but also generate electromagnetic waves with a higher order of OAM *** model can meet the basic demands of ordinary array antenna,and also confirm the practicality of this circular polarized microstrip antenna array model.

关键词： orbital angular momentum array antenna circular polarization RF switch vortex electromagnetic wave spectrum efficiency

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Cross-layer Design for Space-time Block Coded MIMO Systems with Imperfect Channel State Information

Cross-layer Design for Space-time Block Coded MIMO Systems w...

引用

2012 IEEE International Conference on Computer Science and Automation Engineering（CSAE 2012）

作者： Xiangbin Yu 1 2 Wenting Tan 1 1 College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics Nanjing China Xin Yin 1 Xiaomin Chen 1 Ying Yang 1 2 National Mobile Communication Research Laboratory Southeast University Nanjing China

By combining adaptive modulation （AM） and automatic repeat request （ARQ）, a cross-layer design （CLD） scheme for MIMO system with space-time block coding （STBC） and imperfect channel state information （CSI） is presented in this paper, and the effect of the imperfect CSI on the system performance is investigated. Based on the imperfect CSI, the probability density function of the effective signal to noise ratio （SNR） is derived, and the fading gain switching thresholds subject to a target packet loss rate and fixed power constraint are also derived. According to these results, closed-form expressions of the average spectrum efficiency （SE） and packet error rate （PER） of the system are further derived, respectively. These derived expressions include some existing expressions with perfect CSI as special cases, and can provide good performance evaluation for the CLD system with imperfect CSI. Numerical results verify the validity of the theoretical analysis. The results show that the SE and PER of the system with imperfect CSI are worse than those with perfect CSI due to the estimation error, but their performance difference will be reduced as estimation accuracy increases.

关键词： cross-layer design imperfect CSI spectrum efficiency space-time block coding MIMO packet error rate

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