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Interference Cancellation in Device-to-Device Communications underlying MU-MIMO Cellular Networks

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China Communications 2019年第4期16卷 75-88页

作者： Yiyang Ni Yuxi Wang hongbo Zhu Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and Telecommunications Jiangsu Second Normal University

This paper investigates the device-to-device(D2 D) communication underlaying multi-user multi-input multi-output(MU-MIMO) cellular networks. It is assumed that D2 D users reuse the downlink time-frequency resources of cellular links, and the base station(BS) is assumed to be equipped with multiple antennas. We investigate the ergodic achievable sum rate of the system when the interference cancellation(IC) precoding strategy is employed at the BS. The distributions of the received signal-to-interference-plus-noise ratio(SINR) for each link are firstly analyzed, and an exact ergodic achievable sum rate of the whole system with closedform expressions is then derived. Furthermore, we present novel upper and lower bounds with simpler expressions, which are later verified to be fairly close to the Monte-Carlo simulations. All the expressions we presented are suitable for arbitrary network topology and arbitrary number of antennas at BS. Based on the derived bounds, the influence of the antennas at BS on system performance is then analyzed. We reveal that the system performance increases along with the number of antennas at BS in a logarithmic way. The accuracy of our analytical results is validated via comparisons with Monte-Carlo simulations.

关键词： interference cancellation D2D communication ergodic achievable sum rate MU-MIMO

Smart Service System(SSS)：A Novel Architecture Enabling Coordination of Heterogeneous Networking Technologies and Devices for Internet of Things

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China Communications 2017年第3期14卷 130-144页

作者： yongan guo hongbo Zhu longxiang yang college of telecommunications & information engineering nanjing university of posts and telecommunicationsnanjing 210003China

In Internet of Things(IoT), the devices or terminals are connected with each other, which can be very diverse over the wireless networks. Unfortunately, the current devices are not designed to communicate with the collocated devices which employ different communication technologies. Consequently, the communication between these devices will be realized only by using the gateway nodes. This will cause the inefficient use of wireless resources. Therefore, in this paper, a smart service system(SSS) architecture is proposed, which consists of smart service terminal(SST), and smart service network(SSN), to realize the Io T in a general environment with diverse communication networks, devices, and services. The proposed architecture has the following advantages: i) the devices in this architecture cover multiple types of terminals and sensor-actuator devices; ii) the communications network therein is a converged network, and will coordinate multiple kinds of existing and emerging networks. This converged network offers ubiquitous access for various sensors and terminals; iii) the architecture has services and applications covering all smart service areas. It also provides theadaptability to new services and applications. A SSS architecture-based smart campus system was developed and deployed. Evaluation experiments of the proposed smart campus system demonstrate the SSS's advantages over the existing counterparts, and verify the effectiveness of the proposed architecture.

关键词：智能服务系统网络技术体系结构 SSS 物联网设备服务终端异构

Deep Learning-Based Prediction of Traffic Accidents Risk for Internet of Vehicles

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China Communications 2022年第2期19卷 214-224页

作者： Haitao Zhao Xiaoqing Li Huiling Cheng Jun Zhang Qin Wang hongbo Zhu School of Communication and Information Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China School of Electronic and Information Engineering The Hong Kong Polytechnic UniversityHong KongChina

With the increasing number of vehicles,traffic accidents pose a great threat to human lives.Hence,aiming at reducing the occurrence of traffic accidents,this paper proposes an algorithm based on a deep convolutional neural network and a random forest to predict accident risks.Specifically,the proposed algorithm includes a feature extractor and a feature classifier,where the former extracts key features using a convolutional neural network and the latter outputs a probability value of traffic accidents using a random forest with multiple decision trees,which indicates the degree of accident risks.Simulations show that the proposed algorithm can achieve higher performance in terms of the Area Under the Curve(AUC)of the Receiver Characteristic Operator as well as accuracy than the existing algorithms based on the Adaboost or the pure convolutional neural networks.

关键词： road safety risk prediction Internet of Vehicles

A Novel Handoff Algorithm for Hierarchical Cellular Networks

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China Communications 2016年第8期13卷 136-147页

作者： Xiaorong zhu Mengrong Li Wenchao Xia hongbo Zhu Nanjing University of Posts and Telecommunications Nanjing China National Mobile Communications Research Laboratory Southeast University Nanjing China

In this paper, we propose a novel speed and service-sensitive handoff algorithm and analytical model for hierarchical cellular networks.First, we use the Gauss-Markov mobility model to predict the speeds of mobile stations, and divide mobile stations into three classes based on the predicted speeds: fast, medium-speed, and slow.Then, according to the mobility classification,network conditions, and service types, mobile stations will be handoff to the proper target networks prior to the deterioration of the currently operating channel. We further develop an analytical model to evaluate the performance of such a hierarchical system with different speed classes and service types. Simulations and analytical results show that the proposed handoff algorithm can significantly improve the network performance in terms of the handoff failure probability, unnecessary handoff probability, and network throughput, comparing with the traditional algorithms.

关键词： Hierarchical cellular networks handoff algorithm Gauss-Markov mobility model analytical model

Service-Oriented Network Virtualization Architecture for Internet of Things

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中国通信：英文版 2016年第9期13卷 163-172页

作者： Yongan Guo hongbo Zhu Longxiang Yang College of Telecommunications&Information Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China Jiangsu Key Lab of Wireless Communications Nanjing University of Posts and TelecommunicationsNanjing 210003China

As a key technology to realize smart services of Internet of Things(Io T),network virtualization technology can support the network diversification and ubiquity,and improve the utilization rate of network resources.This paper studies the service-oriented network virtualization architecture for Io T services.Firstly the semantic description method for Io T services is proposed,then the resource representation model and resource management model in the environment of network virtualization are presented.Based on the above models,the service-oriented virtual network architecture for Io T is established.Finally,a smart campus system is designed and deployed based on the service-oriented virtual network architecture.Moreover,the proposed architecture and models are verified in experiments.

关键词：虚拟化技术面向服务物联网架构资源管理模型网络体系结构网络资源智能服务

High fidelity numerical simulations on the unsteady flow field of low-pressure turbine cascades with and without upstream disturbance at moderate Reynolds number

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Advances in Aerodynamics 2022年第1期4卷 203-217页

作者： hongbo Zhu Xiyuan Pang Feng Wu Chunxiao Zhang Yan Bao Hui Xu School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China AECC Sichuan Gas Turbine Establishment Mianyang621000China Inner Mongolia Road and Bridge Group Co. LtdHuhhot010000China School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai200240China

This paper numerically investigates the aerodynamic performance of the T106A low-pressure turbine based with different inflow conditions at moderate Reynolds number by using high performance computing based on high order unstructured methods.Two different inflow conditions respectively of uniform and disturbed are considered,while for the latter a small circular cylinder is placed upstream of the cascade to generate wake turbulence as a long-standing disturbance.A high order Fourier-spectral/hp element method is employed to solve the flow dynamics in the cascade of high complex geometries.Flow transition characteristics are quantified in terms of the distribution of cascade wall surface pressure and friction coefficient,the distribution of wake profile pressure loss and the evolution characteristics of boundary layer flow structures as well.The numerical results show that the current numerical simulations accurately predict the flow transition performance of low-pressure turbine cascades and capture the effects of wake-generated disturbance on the cascade,which is shown to effectively modify the flow transition performance as compared with the uniform inflow case.

关键词： Fourier-spectral/hp element method Low pressure turbine Wake generated disturbance Aerodynamic characteristics

Estimation of the radiation backgrounds in the CEPC vertex detector

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Radiation Detection Technology and Methods 2022年第2期6卷 170-178页

作者： Wei Xu Haoyu Shi hongbo Zhu Ke Li Sha Bai Xinchou Lou Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China School of Physics Zhejiang UniversityHangzhou 310058China Department of Physics University of WashingtonSeattleWA 98195USA

Background The Circular Electron-Positron Collider(CEPC)is aimed for precision measurements of the Higgs boson properties and the electroweak parameters.The achievable precision will be largely dependent on the controlled level of radiation backgrounds,which requires an optimized design of the interaction region to assure the optimal performance of both the accelerator and the detectors.Purpose In this article,the latest results on the radiation backgrounds are reported based on the accelerator parameters and the detector design presented in the CEPC conceptual design reports.Method For the different sources of radiation backgrounds,simulation steps consisting of generation,tracking,and detector simulation were performed.Radiation backgrounds from the processes of synchrotron radiation,pair production,radiative Bhabha scattering,beam gas Bremsstrahlung scattering,and beam thermal photon scattering were considered for the accel-erator operating at the different centre-of-mass energies(HZ threshold,WW threshold,and Z pole).Possible mitigation methods of masks and/or collimators were introduced to suppress the radiation backgrounds,together with the careful opti-mization of the interaction region design.With the improved tracking methods during simulation,the accuracy and reliability of the results were improved.In addition,the radiation backgrounds on the CEPC vertex detector were estimated,and the pair-production was found to be the most important source.Result In the worst case of operation at the Z pole,the vertex detector would have to withstand a total ionization dose of 5.6 Mrad per year and a non-ionization energy loss(shown in 1 MeV neutron equivalent)of 1.06×10^(13)n_(eq)/cm^(2)per year.

关键词： CEPC Interaction region Beam-induced background Vertex detector

Spectral Efficiency of Superimposed Pilots in Cell-Free Massive MIMO Systems with Hardware Impairments

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China Communications 2021年第6期18卷 146-161页

作者： Yao Zhang Meng Zhou Haitao Zhao Longxiang Yang hongbo Zhu The Department of Wireless Communication Key Lab of Jiangsu Province Nanjing University of Posts and TelecommunicationsNanjing 210003China

In this paper,the spectral efficiency(SE)of an uplink hardware-constrained cell-free massive multi-input multi-output(MIMO)system with maximal ratio combining(MRC)receiver filters in the context of superimposed pilots(SPs)is investigated.Tractable closed-form SE expressions for the considered system are derived,which share us with opportunities to explore the impacts of the hardware quality coefficient,the length of coherence interval,and the power balance factor between pilot and data signals.Numerical results indicate that the achievable SE deteriorates as the hardware quality decreases and is more susceptible to the hardware impairments at the user equipments(UEs).Besides,we observe that SPs outperform regular pilots(RPs)in terms of SE and this performance gain is heavily dependent on the values of power balance factor and coherence interval.However,the superiorities of SPs over RPs have vanished when severe hardware imperfections are considered.

关键词： cell-free massive MIMO hardware impairments superimposed pilots spectral efficiency

Power Allocation for NOMA in D2D Relay Communications

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China Communications 2021年第1期18卷 61-69页

作者： Yan Cai Chunhua Ke Yiyang Ni Jun Zhang hongbo Zhu Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and TelecommunicationsNanjing 210003China Jiangsu Second Normal University Nanjing 210013China

Non-orthogonal multiple access(NOMA)is considered as one of the key technologies for the fifth generation(5G)wireless communications.The integration of NOMA and device-to-device(D2D)communications has recently attracted wide attention.In this paper,a relaying D2D communications assisted with cooperative relaying systems using NOMA(DRC-NOMA)is considered.We analyze the ergodic sum-rate for the proposed system and then derive the closed-form expressions.In addition,an optimal power allocation strategy maximizing the ergodic sum-rate is proposed based on these analysis results.Numerical results show the good agreement between the results of analysis and Monte Carlo method.The proposed DRC-NOMA has a great improvement of the ergodic sum-rate in the small regime of average channel gain of D2D pair.

关键词： device-to-device communication nonorthogonal multiple access decode-and-forward relaying power allocation rate analysis