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    Modulation Techniques for Li-Fi
    Mohamed Sufyan Islim, Harald Haas
    ZTE Communications    2016, 14 (2): 29-40.   DOI: 10.3969/j.issn.1673-5188.2016.02.004
    Abstract1270)      PDF (476KB)(772)       Save
    Modulation techniques for light fidelity (Li-Fi) are reviewed in this paper. Li-Fi is the fully networked solution for multiple users that combines communication and illumination simultaneously. Light emitting diodes (LEDs) are used in Li-Fi as visible light transmitters, therefore, only intensity modulated direct detected modulation techniques can be achieved. Single carrier modulation techniques are straightforward to be used in Li-Fi, however, computationally complex equalization processes are required in frequency selective Li-Fi channels. On the other hand, multicarrier modulation techniques offer a viable solution for Li-Fi in terms of power, spectral and computational efficiency. In particular, orthogonal frequency division multiplexing (OFDM) based modula-tion techniques offer a practical solution for Li-Fi, especially when direct current (DC) wander, and adaptive bit and power loading techniques are considered. Li-Fi modulation techniques need to also satisfy illumination requirements. Flickering avoidance and dimming control are considered in the variant modulation techniques presented. This paper surveys the suitable modulation techniques for Li-Fi including those which explore time, frequency and colour domains.
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    Introduction to Cloud Manufacturing
    Li Bohu, Zhang Lin, Chai Xudong
    ZTE Communications    2010, 8 (4): 6-9.  
    Abstract1197)      PDF (640KB)(584)       Save
    Cloud manufacturing is a new, networked and intelligent manufacturing model that is service-oriented, knowledge based, high performance, and energy efficient. In this model, state-of-the-art technologies such as informatized manufacturing, cloud computing, Internet of Things, semantic Web, and high-performance computing are integrated in order to provide secure, reliable, and high quality on-demand services at low prices for those involved in the whole manufacturing lifecycle. As an important part of cloud manufacturing, cloud simulation technology based on the COSIM-CSP platform has primarily been applied in the design of a multidisciplinary virtual prototype of a flight vehicle. This lays the foundation for further research into cloud manufacturing.
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    Analysis of Hot Topics in Cloud Computing
    Li Deyi, Chen Guisheng, Zhang Haisu
    ZTE Communications    2010, 8 (4): 1-5.  
    Abstract769)      PDF (521KB)(548)       Save
    In the field of cloud computing, topics such as computing resource virtualization, differences between grid and cloud computing, relationship between high-performance computers and cloud computing centers, and cloud security and standards have attracted much research interest. This paper analyzes these topics and highlights that resource virtualization allows information services to be scalable, intensive, and specialized; grid computing involves using many computers for large-scale computing tasks, while cloud computing uses one platform for multiple services; high-performance computers may not be suitable for a cloud computing; security in cloud computing focuses on trust management between service suppliers and users; and based on the existing standards, standardization of cloud computing should focus on interoperability between services
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    Services and Key Technologies of the Internet of Things
    Xing Xiaojiang, Wang Jianli, Li Mingdong
    ZTE Communications    2010, 8 (2): 26-29.  
    Abstract702)      PDF (451KB)(714)       Save
    This article introduces the services and development of the Internet of Things, and analyzes the driving forces and obstacles behind such development. Looking at application types and the different development stages of the Internet of Things, this article categorizes its services into four types: identity related services, information aggregation services, collaborative-aware services, and ubiquitous services. For the first two types of services, applications and system framework are discussed; for the last two types, development trends are discussed. Services provided by the Internet of Things will gradually be integrated into human life and society; with the development of the Internet of Things, applications will evolve from relatively simple identity-related and information aggregation-related applications, to collaboratively-aware, and finally ubiquitous applications. It will then be possible for the Internet of Things to be fully integrated with Internet and telecommunications networks.
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    Cloud Computing: Concept, Model, and Key Technologies
    Kevin Yin
    ZTE Communications    2010, 8 (4): 21-26.  
    Abstract471)      PDF (468KB)(525)       Save
    Cloud computing is a new network computing paradigm based on IP architecture, and its potential lies in new ICT business applications. For the majority of operators and enterprises, the main task associated with cloud computing is next generation data center transformation. This will ensure cloud computing becomes more widespread among enterprises, institutions, organizations, and operators. Cloud computing not only provides traditional IT resource usage and application services, but also supports full resource usage and application services such as IT, communications, video, mobile, and Internet of Things using a converged network infrastructure. Key cloud computing technologies include unified fabric, unified virtualization, and unified computing system. The formation of an open industry alliance and promotion of open technology standards will be critical for the future development of cloud computing.
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    A Survey on Machine Learning Based Proactive Caching
    Stephen ANOKYE, Mohammed SEID, SUN Guolin
    ZTE Communications    2019, 17 (4): 46-55.   DOI: 10.12142/ZTECOM.201904007
    Abstract367)   HTML199)    PDF (1032KB)(397)       Save

    The world today is experiencing an enormous increase in data traffic, coupled with demand for greater quality of experience (QoE) and performance. Increasing mobile traffic leads to congestion of backhaul networks. One promising solution to this problem is the mobile edge network (MEN) and consequently mobile edge caching. In this paper, a survey of mobile edge caching using machine learning is explored. Even though a lot of work and surveys have been conducted on mobile edge caching, our efforts in this paper are rather focused on the survey of machine learning based mobile edge caching. Issues affecting edge caching, such as caching entities, caching policies and caching algorithms, are discussed. The machine learning algorithms applied to edge caching are reviewed followed by a discussion on the challenges and future works in this field. This survey shows that edge caching can reduce delay and subsequently the backhaul traffic of the network; most caching is conducted at the small base stations (SBSs) and caching at unmanned aerial vehicles (UAVs) is recently used to accommodate mobile users who dissociate from SBSs. This survey also demonstrates that machine learning approach is the state of the art and reinforcement learning is predominant.

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    5G New Radio: Physical Layer Overview
    YUAN Yifei, WANG Xinhui
    ZTE Communications    2017, 15 (S1): 3-10.   DOI: 10.3969/j.issn.1673-5188.2017.S1.001
    Abstract312)   HTML113)    PDF (494KB)(358)       Save

    This paper provides an overview of the physical layer of 5G new radio (NR) system. A general framework of 5G NR is first described, which glues together various key components, all of them helping to fulfill the requirements of three major deployment scenarios: enhanced mobile broadband (eMBB), ultra-reliable low latency communications (URLLC) and massive machine type communications (mMTC). Then, several key components of the 5G NR physical layer are discussed in more detail that include multiple access, channel coding, multiple antennas, frame structures, and initial access. The two-phase approach of NR is also discussed and the key technologies expected to be specified in Phase 1 and Phase 2 are listed.

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    An Overview of Non-Orthogonal Multiple Access
    Anass Benjebbour
    ZTE Communications    2017, 15 (S1): 21-30.   DOI: 10.3969/j.issn.1673-5188.2017.S1.003
    Abstract311)   HTML120)    PDF (519KB)(261)       Save

    In recent years, non-orthogonal multiple access (NOMA) has attracted a lot of attention as a novel and promising power-domain user multiplexing scheme for Long-Term Evolution (LTE) enhancement and 5G. NOMA is able to contribute to the improvement of the tradeoff between system capacity and user fairness (i.e., cell-edge user experience). This improvement becomes in particular emphasized in a cellular system where the channel conditions vary significantly among users due to the near-far effect. In this article, we provide an overview of the concept, design and performance of NOMA. In addition, we review the potential benefits and issues of NOMA over orthogonal multiple access (OMA) such as orthogonal frequency division multiple access (OFDMA) adopted by LTE, and the status of 3GPP standardization related to NOMA.

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    Cloud Storage Technology and Its Applications
    Zhou Ke, Wang Hua, Li Chunhua
    ZTE Communications    2010, 8 (4): 27-30.  
    Abstract282)      PDF (521KB)(216)       Save
    Cloud storage employs software that interconnects and facilitates collaboration between different types of storage devices. Compared with traditional storage methods, cloud storage poses new challenges in data security, reliability, and management. This paper introduces four layers of cloud storage architecture: data storage layer (connecting multiple storage components), data management layer (providing common support technology for multiple services), data service layer (sustaining multiple storage applications), and user access layer. A typical cloud storage application—Backup Cloud (B-Cloud)—is examined and its software architecture, characteristics, and main research areas are discussed.
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    Big-Data Processing Techniques and Their Challenges in Transport Domain
    Aftab Ahmed Chandio, Nikos Tziritas, Cheng-Zhong Xu
    ZTE Communications    2015, 13 (1): 50-59.   DOI: 10.3969/j.issn.1673-5188.2015.01.007
    Abstract270)      PDF (453KB)(153)       Save
    This paper describes the fundamentals of cloud computing and current big-data key technologies. We categorize big-data processing as batch-based, stream-based, graph-based, DAG-based, interactive-based, or visual-based according to the processing technique. We highlight the strengths and weaknesses of various big-data cloud processing techniques in order to help the big-data community select the appropriate processing technique. We also provide big data research challenges and future directions in aspect to transportation management systems.
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    A General SDN-Based IoT Framework with NVF Implementation
    Jie Li, Eitan Altman, Corinne Touati
    ZTE Communications    2015, 13 (3): 42-45.   DOI: 10.3969/j.issn.1673-5188.2015.03.006
    Abstract269)      PDF (408KB)(299)       Save
    The emerging technologies of Internet of Things (IoT), software defined networking (SDN), and network function virtualization (NFV) have great potential for the information service innovation in the cloud and big data era. The architecture models of IoT, SDN with NFV implementation are studied in this paper. A general SDN-based IoT framework with NFV implantation is presented. This framework takes advantages of SDN and NFV and improves IoT architecture.
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    Non-Orthogonal Multiple Access Schemes for 5G
    YAN Chunlin, YUAN Zhifeng, LI Weimin, YUAN Yifei
    ZTE Communications    2016, 14 (4): 11-16.   DOI: 10.3969/j.issn.1673-5188.2016.04.002
    Abstract268)      PDF (424KB)(152)       Save
    Multiple access scheme is one of the key techniques in wireless communication systems. Each generation of wireless communication is featured by a new multiple access scheme from 1G to 4G. In this article we review several non?orthogonal multiple access schemes for 5G. Their principles, advantages and disadvantages are discussed, and followed by a comprehensive comparison of these solutions from the perspective of user overload, receiver type, receiver complexity and so on. We also discuss the application challenges of non?orthogonal multiple access schemes in 5G.
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    Security Enhanced Internet of Vehicles with Cloud-Fog-Dew Computing
    MENG Ziqian, GUAN Zhi, WU Zhengang, LI Anran, CHEN Zhong
    ZTE Communications    2017, 15 (S2): 47-51.   DOI: 10.3969/j.issn.1673-5188.2017.S2.008
    Abstract259)   HTML177)    PDF (324KB)(281)       Save

    The Internet of Vehicles (IoV) is becoming an essential factor in the development of smart transportation and smart city projects. The IoV technology consists of the concepts of fog computing and dew computing, which involve on-board units and road side units in the edge network, as well as the concept of cloud computing, which involves the data center that provides service. The security issues are always an important concern in the design of IoV architecture. To achieve a secure IoV architecture, some security measures are necessary for the cloud computing and fog computing associated with the vehicular network. In this paper, we summarize some research works on the security schemes in the vehicular network and cloud-fog-dew computing platforms which the IoV depends on.

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    Signal Detection and Channel Estimation in OTFS
    NAIKOTI Ashwitha, CHOCKALINGAM Ananthanarayanan
    ZTE Communications    2021, 19 (4): 16-33.   DOI: 10.12142/ZTECOM.202104003
    Abstract253)   HTML8)    PDF (2749KB)(494)       Save

    Orthogonal time frequency space (OTFS) modulation is a recently proposed modulation scheme that exhibits robust performance in high-Doppler environments. It is a two-dimensional modulation scheme where information symbols are multiplexed in the delay-Doppler (DD) domain. Also, the channel is viewed in the DD domain where the channel response is sparse and time-invariant for a long time. This simplifies channel estimation in the DD domain. This paper presents an overview of the state-of-the-art approaches in OTFS signal detection and DD channel estimation. We classify the signal detection approaches into three categories, namely, low-complexity linear detection, approximate maximum a posteriori (MAP) detection, and deep neural network (DNN) based detection. Similarly, we classify the DD channel estimation approaches into three categories, namely, separate pilot approach, embedded pilot approach, and superimposed pilot approach. We compile and present an overview of some of the key algorithms under these categories and illustrate their performance and complexity attributes.

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    Barcelona Smart City: The Heaven on Earth (Internet of Things: Technological God)
    Somayya Madakam, Ramaswamy Ramachandran
    ZTE Communications    2015, 13 (4): 3-9.   DOI: 10.3969/j.issn.1673-5188.2015.04.001
    Abstract236)      PDF (564KB)(206)       Save
    Cities are the most preferable dwelling places, having with better employment opportunities, educational hubs, medical services, recreational facilities, theme parks, and shopping malls etc. Cities are the driving forces for any national economy too. Unfortunately now a days, these cities are producing circa 70% of pollutants, even though they only occupy 2% of surface of the Earth. Public utility services cannot meet the demands of unexpected growth. The filthiness in cities causing decreasing of Quality of Life. In this light our research paper is giving more concentration on necessity of “Smart Cities”, which are the basis for civic centric services. This article is throwing light on Smart Cities and its important roles. The beauty of this manuscript is scribbling “Smart Cities” concepts in pictorially. Moreover this explains on“Barcelona Smart City”using Internet of Things Technologies”. It is a good example in urban paradigm shift. Bracelona is like the heaven on the earth with by providing Quality of Life to all urban citizens. The GOD is Interenet of Things.
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    Virtualization Technology in Cloud Computing Based Radio Access Networks: A Primer
    ZHANG Xian, PENG Mugen
    ZTE Communications    2017, 15 (4): 47-66.   DOI: 10.3969/j.issn.1673-5188.2017.04.007
    Abstract220)   HTML106)    PDF (721KB)(178)       Save

    Since virtualization technology enables the abstraction and sharing of resources in a flexible management way, the overall expenses of network deployment can be significantly reduced. Therefore, the technology has been widely applied in the core network. With the tremendous growth in mobile traffic and services, it is natural to extend virtualization technology to the cloud computing based radio access networks (CC-RANs) for achieving high spectral efficiency with low cost. In this paper, the virtualization technologies in CC-RANs are surveyed, including the system architecture, key enabling techniques, challenges, and open issues. The enabling key technologies for virtualization in CC-RANs mainly including virtual resource allocation, radio access network (RAN) slicing, mobility management, and social-awareness have been comprehensively surveyed to satisfy the isolation, customization and high-efficiency utilization of radio resources. The challenges and open issues mainly focus on virtualization levels for CC-RANs, signaling design for CC-RAN virtualization, performance analysis for CC-RAN virtualization, and network security for virtualized CC-RANs.

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    Introduction to Point Cloud Compression
    XU Yiling, ZHANG Ke, HE Lanyi, JIANG Zhiqian, ZHU Wenjie
    ZTE Communications    2018, 16 (3): 3-8.   DOI: 10.19729/j.cnki.1673-5188.2018.03.002
    Abstract220)   HTML199)    PDF (368KB)(298)       Save

    Characterized by geometry and photometry attributes, point cloud has been widely applied in the immersive services of various 3D objects and scenes. The development of even more precise capture devices and the increasing requirements for vivid rendering inevitably induce huge point capacity, thus making the point cloud compression a demanding issue. In this paper, we introduce several well-known compression algorithms in the research area as well as the boosting industry standardization works. Specifically, based on various applications of this 3D data, we summarize the static and dynamic point cloud compression, both including irregular geometry and photometry information that represent the spatial structure information and corresponding attributes, respectively. In the end, we conclude the point cloud compression as a promising topic and discuss trends for future works.

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    A Network Traffic Prediction Method Based on LSTM
    WANG Shihao, ZHUO Qinzheng, YAN Han, LI Qianmu, QI Yong
    ZTE Communications    2019, 17 (2): 19-25.   DOI: 10.12142/ZTECOM.201902004
    Abstract206)   HTML90)    PDF (1526KB)(132)       Save

    As the network sizes continue to increase, network traffic grows exponentially. In this situation, how to accurately predict network traffic to serve customers better has become one of the issues that Internet service providers care most about. Current traditional network models cannot predict network traffic that behaves as a nonlinear system. In this paper, a long short-term memory (LSTM) neural network model is proposed to predict network traffic that behaves as a nonlinear system. According to characteristics of autocorrelation, an autocorrelation coefficient is added to the model to improve the accuracy of the prediction model. Several experiments were conducted using real-world data, showing the effectiveness of LSTM model and the improved accuracy with autocorrelation considered. The experimental results show that the proposed model is efficient and suitable for real-world network traffic prediction.

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    Millimeter Wave and Terahertz Communications: Feasibility and Challenges
    Phil Pietraski, David Britz, Arnab Roy, Ravi Pragada, and Gregg Charlton
    ZTE Communications    2012, 10 (4): 3-12.  
    Abstract204)      PDF (624KB)(136)       Save
    In this paper, the challenges with and motivations for developing millimeter wave and terahertz communications are described. A high-level candidate architecture is presented, and use cases highlighting the potential applicability of high-frequency links are discussed. Mobility challenges at these higher frequencies are also discussed. Difficulties that arise as a result of high carrier frequencies and higher path loss can be overcome by practical, higher-gain antennas that have the added benefit of reducing intercell interference. Simulation methodology and results are given. The results show that millimeter wave coverage is possible in large, outdoor spaces, and only a reasonable number of base stations are needed. Network throughput can exceed 25 Gbit/s, and cell-edge user throughput can reach approximately 100 Mbit/s.
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    5G New Radio (NR): Standard and Technology
    Fa-Long Lu
    ZTE Communications    2017, 15 (S1): 1-2.  
    Abstract203)   HTML11)    PDF (200KB)(194)       Save
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    A Secure Key Management Scheme for Heterogeneous Secure Vehicular Communication Systems
    LEI Ao, Chibueze Ogah, Philip Asuquo, Haitham Cruickshank, SUN Zhili
    ZTE Communications    2016, 14 (S0): 21-31.   DOI: 10.3969/j.issn.1673-5188.2016.S0.004
    Abstract196)      PDF (1094KB)(118)       Save
    Intelligent transportation system (ITS) is proposed as the most effective way to improve road safety and traffic efficiency. However, the future of ITS for large scale transportation infrastructures deployment highly depends on the security level of vehicular communication systems (VCS). Security applications in VCS are fulfilled through secured group broadcast. Therefore, secure key management schemes are considered as a critical research topic for network security. In this paper, we propose a framework for providing secure key management within heterogeneous network. The security managers (SMs) play a key role in the framework by retrieving the vehicle departure information, encapsulating block to transport keys and then executing rekeying to vehicles within the same security domain. The first part of this framework is a novel Group Key Management (GKM) scheme basing on leaving probability (LP) of vehicles to depart current VCS region. Vehicle's LP factor is introduced into GKM scheme to achieve a more efficient rekeying scheme and less rekeying costs. The second component of the framework using the blockchain concept to simplify the distributed key management in heterogeneous VCS domains. Extensive simulations and analysis are provided to show the effectiveness and efficiency of the proposed framework: Our GKM results demonstrate that probability-based BR reduces rekeying cost compared to the benchmark scheme, while the blockchain decreases the time cost of key transmission over heterogeneous networks.
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    Development of Trusted Network and Challenges It Faces
    Lin Chuang, Wang Yuanzhuo, Tian Liqin
    ZTE Communications    2008, 6 (1): 13-17.  
    Abstract193)      PDF (280KB)(115)       Save
    As the information network plays a more and more important role globally, the traditional network theories and technologies , especially those related to network security, can no longer meet the network development requirements . Offering the system with secure and trusted services has become a new focus in network res earch . This paper first discusses the meaning of and aspects involved in the trusted network. According to this paper, the trusted network should be a network where the network s and users behaviors and their results are always predicted and manageable . The trustworthiness of a network mainly involves three aspects : service provider, information transmission and terminal user. This paper also analyzes the trusted network in terms of trusted model for network/user behaviors , architecture of trusted network, s ervice survivability and network manageability, which is designed to give ideas on solving the problems that may be faced in developing the trusted network.
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    A Case Study on Intelligent Operation System for Wireless Networks
    LIU Jianwei, YUAN Yifei, HAN Jing
    ZTE Communications    2019, 17 (4): 19-26.   DOI: 10.12142/ZTECOM.201904004
    Abstract180)   HTML186)    PDF (1189KB)(172)       Save

    The emerging fifth generation (5G) network has the potential to satisfy the rapidly growing traffic demand and promote the transformation of smartphone-centric networks into an Internet of Things (IoT) ecosystem. Due to the introduction of new communication technologies and the increased density of 5G cells, the complexity of operation and operational expenditure (OPEX) will become very challenging in 5G. Self-organizing network (SON) has been researched extensively since 2G, to cope with the similar challenge, however by predefined policies, rather than intelligent analysis. The requirement for better quality of experience and the complexity of 5G network demands call for an approach that is different from SON. In several recent studies, the combination of machine learning (ML) technology with SON has been investigated. In this paper, we focus on the intelligent operation of wireless network through ML algorithms. A comprehensive and flexible framework is proposed to achieve an intelligent operation system. Two use cases are also studied to use ML algorithms to automate the anomaly detection and fault diagnosis of key performance indicators (KPIs) in wireless networks. The effectiveness of the proposed ML algorithms is demonstrated by the real data experiments, thus encouraging the further research for intelligent wireless network operation.

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    Machine Learning Based Unmanned Aerial Vehicle Enabled Fog-Radio Aerial Vehicle Enabled Fog-Radio Access Network and Edge Computing
    Mohammed SEID, Stephen ANOKYE, SUN Guolin
    ZTE Communications    2019, 17 (4): 33-45.   DOI: 10.12142/ZTECOM.201904006
    Abstract177)   HTML79)    PDF (1257KB)(157)       Save

    The emerging unmanned aerial vehicle (UAV) technology and its applications have become part of the massive Internet of Things (mIoT) ecosystem for future cellular networks. Internet of things (IoT) devices have limited computation capacity and battery life and the cloud is not suitable for offloading IoT tasks due to the distance, latency and high energy consumption. Mobile edge computing (MEC) and fog radio access network (F-RAN) together with machine learning algorithms are an emerging approach to solving complex network problems as described above. In this paper, we suggest a new orientation with UAV enabled F-RAN architecture. This architecture adopts the decentralized deep reinforcement learning (DRL) algorithm for edge IoT devices which makes independent decisions to perform computation offloading, resource allocation, and association in the aerial to ground (A2G) network. Additionally, we summarized the works on machine learning approaches for UAV networks and MEC networks, which are related to the suggested architecture and discussed some technical challenges in the smart UAV-IoT, F-RAN 5G and Beyond 5G (6G).

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    Towards Converged Millimeter-Wave/TerahertzWireless Communication and Radar Sensing
    GAO Xiang, MUHAMMAD Saqlain, CAO Xiaoxiao, WANG Shiwei, LIU Kexin, ZHANG Hangkai, YU Xianbin
    ZTE Communications    2020, 18 (1): 73-82.   DOI: 10.12142/ZTECOM.202001011
    Abstract174)   HTML48)    PDF (1219KB)(226)       Save

    Converged communication and radar sensing systems have attained increasing attention in recent years. The development of converged radar-data systems is reviewed, with a special focus on millimeter/terahertz systems as a promising trend. Firstly, we present historical development and convergence technology concept for communication-radar systems, and highlight some emerging technologies in this area. We then provide an updated and comprehensive survey of several converged systems operating in different microwave and millimeter frequency bands, by providing some selective typical communication and radar sensing systems. In this part, we also summarize and compare the system performance in terms of maximum range/range resolution for radar mode and Bit Error Rate (BER) /wireless distance for communication mode. In the last section, the convergence of millimeter/terahertz communication-radar system is concluded by analyzing the prospect of millimeter-wave/terahertz technologies in providing ultrafast data rates and high resolution for our smart future.

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    Payload Encoding Representation from Transformer for Encrypted Traffic Classification
    HE Hongye, YANG Zhiguo, CHEN Xiangning
    ZTE Communications    2021, 19 (4): 90-97.   DOI: 10.12142/ZTECOM.202104010
    Abstract173)   HTML23)    PDF (965KB)(209)       Save

    Traffic identification becomes more important, yet more challenging as related encryption techniques are rapidly developing nowadays. Unlike recent deep learning methods that apply image processing to solve such encrypted traffic problems, in this paper, we propose a method named Payload Encoding Representation from Transformer (PERT) to perform automatic traffic feature extraction using a state-of-the-art dynamic word embedding technique. By implementing traffic classification experiments on a public encrypted traffic data set and our captured Android HTTPS traffic, we prove the proposed method can achieve an obvious better effectiveness than other compared baselines. To the best of our knowledge, this is the first time the encrypted traffic classification with the dynamic word embedding has been addressed.

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    Smart Cities in Europe and the ALMA Logistics Project
    Didier El Baz, Julien Bourgeois
    ZTE Communications    2015, 13 (4): 10-15.   DOI: 10.3969/j.issn.1673-5188.2015.04.002
    Abstract173)      PDF (360KB)(139)       Save
    In this paper, a brief survey of smart citiy projects in Europe is presented. This survey shows the extent of transport and logistics in smart cities. We concentrate on a smart city project we have been working on that is related to A Logistic Mobile Application (ALMA). The application is based on Internet of Things and combines a communication infrastructure and a High Performance Computing infrastructure in order to deliver mobile logistic services with high quality of service and adaptation to the dynamic nature of logistic operations.
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    5G: Vision, Scenarios and Enabling Technologies
    Yifei Yuan, Xiaowu Zhao
    ZTE Communications    2015, 13 (1): 3-10.   DOI: 10.3969/j.issn.1673-5188.2015.01.001
    Abstract171)      PDF (443KB)(133)       Save
    This paper presents the authors ’vision for 5G wireless systems, which are expected to be standardized around 2020 (IMT-2020). In the future, ubiquitous service will be the key requirement from an end-user ’s prospective, and 5G networks will need to support a vast mesh of human-to-human, human-to-machine, and machine-to-machine connections. Moreover, 5G will need to support these connections in an energy-efficient manner. Various 5G enabling technologies have been extensively discussed. These technologies aim to increase radio link efficiency, expand operating bandwidths, and increase cell density. With these technologies, 5G systems can accommodate a massive volume of traffic and a massive number of connections, which is fundamental to providing ubiquitous services. Another aspect of 5G technology is the transition to an intelligent cloud that coordinates network access and enables flatter architecture.
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    DexDefender: A DEX Protection Scheme to Withstand Memory Dump Attack Based on Android Platform
    RONG Yu, LIU Yiyi, LI Hui, WANG Wei
    ZTE Communications    2018, 16 (3): 45-51.   DOI: 10.19729/j.cnki.1673-5188.2018.03.008
    Abstract169)   HTML50)    PDF (457KB)(193)       Save

    Since Dalvik Executable (DEX) files are prone to be reversed to the Java source code using some decompiling tools, how to protect the DEX files from attackers becomes an important research issue. The traditional way to protect the DEX files from reverse engineering is to encrypt the entire DEX file, but after the complete plain code has been loaded into the memory while the application is running, the attackers can retrieve the code by using memory dump attack. This paper presents a novel DEX protection scheme to withstand memory dump attack on the Android platform with the name of DexDefender, which adopts the dynamic class-restoration method to ensure that the complete plain DEX data not appear in the memory while the application is being loaded into the memory. Experimental results show that the proposed scheme can protect the DEX files from both reverse engineering and memory dump attacks with an acceptable performance.

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    Wireless Mesh Technology and Network
    Zhu Jinkang
    ZTE Communications    2008, 6 (2): 1-6.  
    Abstract169)      PDF (4517KB)(160)       Save
    Wireless Mesh Network (WMN) has been actively res earched and developed as a new network technology to support broadband high - speed multimedia services . This paper dis cuss es WMN technology and applications , and introduces the basic technologies , typical applications and current development of the WMN. With the future development of wireless distribution technology and network, wireless Mesh technology and network will become the key networking technology and architecture of wireless mobile communications , and will be widely us ed in various wireless networks with more important roles .
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    A Survey of Mobile Cloud Computing
    Xiaopeng Fan, Jiannong Cao, and Haixia Mao
    ZTE Communications    2011, 9 (1): 4-8.  
    Abstract169)      PDF (305KB)(109)       Save
    Mobile Cloud Computing (MCC) is emerging as one of the most important branches of cloud computing. In this paper, MCC is defined as cloud computing extended by mobility, and a new ad-hoc infrastructure based on mobile devices. It provides mobile users with data storage and processing services on a cloud computing platform. Because mobile cloud computing is still in its infancy, we aim to clarify confusion that has arisen from different views. Existing works are reviewed, and an overview of recent advances in mobile cloud computing is provided. We investigate representative infrastructures of mobile cloud computing and analyze key components. Moreover, emerging MCC models and services are discussed, and challenging issues are identified that will need to be addressed in future work.
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    Subcarrier Intensity Modulated Optical Wireless Communications:A Survey from Communication Theory Perspective
    Md Zoheb Hassan, Md Jahangir Hossain, Julian Cheng, Victor C M Leung
    ZTE Communications    2016, 14 (2): 2-12.   DOI: 10.3969/j.issn.1673-5188.2016.02.001
    Abstract168)      PDF (418KB)(86)       Save
    Subcarrier intensity modulation with direct detection is a modulation/detection technique for optical wireless communication systems, where a pre-modulated and properly biased radio frequency signal is modulated on the intensity of the optical carrier. The most important benefits of subcarrier intensity modulation are as follows: 1) it does not provide irreducible error floor like the conventional on-off keying intensity modulation with a fixed detection threshold; 2) it provides improved spectral efficiency and supports higher order modulation schemes; and 3) it has much less implementation complexity compared to coherent optical wireless communications with heterodyne or homodyne detection. In this paper, we present an up-to-date review of subcarrier intensity modulated optical wireless communication systems. We survey the error rate and outage performance of subcarrier intensity modulations in the atmospheric turbulence channels considering different modulation and coding schemes. We also explore different contemporary atmospheric turbulence fading mitigation solutions that can be employed for subcarrier intensity modulation. These solutions include diversity combining, adaptive transmission, relay assisted transmission, multiple-subcarrier intensity modulations, and optical orthogonal frequency division multiplexing. Moreover, we review the performance of subcarrier intensity modulations due to the pointing error and synchronization error.
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    Enabling Energy Efficiency in 5G Network
    LIU Zhuang, GAO Yin, LI Dapeng, CHEN Jiajun, HAN Jiren
    ZTE Communications    2021, 19 (1): 20-29.   DOI: 10.12142/ZTECOM.202101004
    Abstract168)   HTML4)    PDF (1356KB)(216)       Save

    The mobile Internet and Internet of Things are considered the main driving forces of 5G, as they require an ultra-dense deployment of small base stations to meet the increasing traffic demands. 5G new radio (NR) access is designed to enable denser network deployments, while leading to a significant concern about the network energy consumption. Energy consumption is a main part of network operational expense (OPEX), and base stations work as the main energy consumption equipment in the radio access network (RAN). In order to achieve RAN energy efficiency (EE), switching off cells is a strategy to reduce the energy consumption of networks during off-peak conditions. This paper introduces NR cell switching on/off schemes in 3GPP to achieve energy efficiency in 5G RAN, including intra-system energy saving (ES) scheme and inter-system ES scheme. Additionally, NR architectural features including central unit/distributed unit (CU/DU) split and dual connectivity (DC) are also considered in NR energy saving. How to apply artificial intelligence (AI) into 5G networks is a new topic in 3GPP, and we also propose a machine learning (ML) based scheme to save energy by switching off the cell selected relying on the load prediction. According to the experiment results in the real wireless environment, the ML based ES scheme can reduce more power consumption than the conventional ES scheme without load prediction.

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    A Novel 28 GHz Phased Array Antenna for 5G Mobile Communications
    LI Yezhen, REN Yongli, YANG Fan, XU Shenheng, ZHANG Jiannian
    ZTE Communications    2020, 18 (3): 20-25.   DOI: 10.12142/ZTECOM.202003004
    Abstract164)   HTML73)    PDF (3130KB)(263)       Save

    A novel phased array antenna consisting of 256 elements is presented and experimentally verified for 5G millimeter-wave wireless communications. The antenna integrated with a wave control circuit can perform real-time beam scanning by reconfiguring the phase of an antenna unit. The unit, designed at 28 GHz using a simple patch structure with one PIN diode, can be electronically controlled to generate 1 bit phase quantization. A prototype of the antenna is fabricated and measured to demonstrate the feasibility of this approach. The measurement results indicate that the antenna achieves high gain and fast beam-steering, with the scan beams within ±60° range and the maximum gain up to 21.7 dBi. Furthermore, it is also tested for wireless video transmission. In ZTE Shanghai, the antenna was used for the 5G New Radio (NR) test. The error vector magnitude (EVM) is less than 3% and the adjacent channel leakage ratio (ACLR) less than -35 dBc, which can meet 5G system requirements. Compared with the conventional phased array antenna, the proposed phased array has the advantages of low power consumption, low cost and conformal geometry. Due to these characteristics, the antenna is promising for wide applications in 5G millimeter-wave communication systems.

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    Enhanced OFDM for 5G RAN
    Zekeriyya Esat Ankaralı, Berker Peköz, Hüseyin Arslan
    ZTE Communications    2017, 15 (S1): 11-20.   DOI: 10.3969/j.issn.1673-5188.2017.S1.002
    Abstract162)   HTML71)    PDF (490KB)(222)       Save

    Support of many different services, approximately 1000x increase of current data rates, ultra-low latency and energy/cost efficiency are among the expectations from the upcoming 5G standards. In order to meet these expectations, researchers investigate various potential technologies involving different network layers and discuss their tradeoffs for possible 5G scenarios. As one of the most critical components of communication systems, waveform design plays a vital role here to achieve the aforementioned goals. Basic features of the 5G waveform can be given in a nutshell as more flexibility, support of multiple access, the ability to co-exist with different waveforms, low latency and compatibility with promising future technologies such as massive MIMO and mmWave communications. Orthogonal frequency division multiplexing (OFDM) has been the dominant technology in many existing standards and is still considered as one of the favorites for broadband communications in 5G radio access network (RAN). Considering the current interest of industry and academia on enhancing OFDM, this paper drafts the merits and shortcomings of OFDM for 5G RAN scenarios and discusses the various approaches for its improvement. What is addressed in this paper includes not only enhancing the waveform characteristics, out of band leakage and peak to average power ratio in particular, but also methods to reduce the time and frequency redundancies of OFDM such as cyclic prefix and pilot signals. We present how the requirements of different 5G RAN scenarios reflect on waveform parameters, and explore the motivations behind designing frames that include multiple waveforms with different parameters, referred to as numerologies by the 3GPP community, as well as the problems that arise with such coexistence. In addition, recently proposed OFDM-based signaling schemes will also be discussed along with a brief comparison.

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    DDoS Attack in Software Defined Networks: A Survey
    XU Xiaoqiong, YU Hongfang, YANG Kun
    ZTE Communications    2017, 15 (3): 13-19.   DOI: 10.3969/j.issn.1673-5188.2017.03.003
    Abstract154)   HTML128)    PDF (360KB)(253)       Save

    Distributed Denial of Service (DDoS) attacks have been one of the most destructive threats to Internet security. By decoupling the network control and data plane, software defined networking (SDN) offers a flexible network management paradigm to solve DDoS attack in traditional networks. However, the centralized nature of SDN is also a potential vulnerability for DDoS attack. In this paper, we first provide some SDN-supported mechanisms against DDoS attack in traditional networks. A systematic review of various SDN-self DDoS threats are then presented as well as the existing literatures on quickly DDoS detection and defense in SDN. Finally, some promising research directions in this field are introduced.

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    ITP Colour Space and Its Compression Performance for High Dynamic Range and Wide Colour Gamut Video Distribution
    Taoran Lu, Fangjun Pu, Peng Yin, Tao Chen, Walt Husak, Jaclyn Pytlarz, Robin Atkins, Jan Fr-hlich, Guan-Ming Su
    ZTE Communications    2016, 14 (1): 32-38.   DOI: 10.3969/j.issn.1673-5188.2016.01.005
    Abstract152)      PDF (532KB)(99)       Save
    High Dynamic Range (HDR) and Wider Colour Gamut (WCG) content represents a greater range of luminance levels and a more complete reproduction of colours found in real-world scenes. The current video distribution environments deliver Standard Dynamic Range (SDR) signal Y′CbCr. For HDR and WCG content, it is desirable to examine if such signal format still works well for compression, and to know if the overall system performance can be further improved by exploring different signal formats. In this paper, ITP (ICTCP) colour space is presented. The paper concentrates on examining the two aspects of ITP colour space: 1) ITP characteristics in terms of signal quantization at a given bit depth; 2) ITP compression performance. The analysis and simulation results show that ITP 10 bit has better properties than Y′CbCr-PQ 10bit in colour quantization, constant luminance, hue property and chroma subsampling, and it also has good compression efficiency. Therefore it is desirable to adopt ITP colour space as a new signal format for HDR/WCG video compression.
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    Leaky-Wave Antennas for 5G/B5G Mobile Communication Systems: A Survey
    HE Yejun, JIANG Jiachun, ZHANG Long, LI Wenting, WONG Sai-Wai, DENG Wei, CHI Baoyong
    ZTE Communications    2020, 18 (3): 3-11.   DOI: 10.12142/ZTECOM.202003002
    Abstract151)   HTML65)    PDF (3449KB)(190)       Save

    Since leaky-wave antennas (LWAs) have the advantages of high directivity, low loss and structural simplicity, LWAs are very suitable for designing millimeter-wave (mmW) antennas. The purpose of this paper is to review the latest research progress of LWAs for 5G/B5G mobile communication systems. Firstly, the conventional classification and design methods of LWAs are introduced and the effects of the phase constant and attenuation constant on the radiation characteristics are discussed. Then two types of new LWAs for 5G/B5G mobile communication systems including broadband fixed-beam LWAs and frequency-fixed beam-scanning LWAs are summarized. Finally, the challenges and future research directions of LWAs for 5G/B5G mobile communication systems are presented.

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    Enabling Intelligence at Network Edge:An Overview of Federated Learning
    YANG Howard H., ZHAO Zhongyuan, QUEK Tony Q. S.
    ZTE Communications    2020, 18 (2): 2-10.   DOI: 10.12142/ZTECOM.202002002
    Abstract150)   HTML244)    PDF (1050KB)(147)       Save

    The burgeoning advances in machine learning and wireless technologies are forging a new paradigm for future networks, which are expected to possess higher degrees of intelligence via the inference from vast dataset and being able to respond to local events in a timely manner. Due to the sheer volume of data generated by end-user devices, as well as the increasing concerns about sharing private information, a new branch of machine learning models, namely federated learning, has emerged from the intersection of artificial intelligence and edge computing. In contrast to conventional machine learning methods, federated learning brings the models directly to the device for training, where only the resultant parameters shall be sent to the edge servers. The local copies of the model on the devices bring along great advantages of eliminating network latency and preserving data privacy. Nevertheless, to make federated learning possible, one needs to tackle new challenges that require a fundamental departure from standard methods designed for distributed optimizations. In this paper, we aim to deliver a comprehensive introduction of federated learning. Specifically, we first survey the basis of federated learning, including its learning structure and the distinct features from conventional machine learning models. We then enumerate several critical issues associated with the deployment of federated learning in a wireless network, and show why and how technologies should be jointly integrated to facilitate the full implementation from different perspectives, ranging from algorithmic design, on-device training, to communication resource management. Finally, we conclude by shedding light on some potential applications and future trends.

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    A Survey of Massive MIMO Channel Measurements and Models
    ZHANG Jianhua, WANG Chao, WU Zhongyuan, ZHANG Weite
    ZTE Communications    2017, 15 (1): 14-22.   DOI: 10.3969/j.issn.1673-5188.2017.01.003
    Abstract150)   HTML72)    PDF (618KB)(139)       Save

    Compared with conventional multiple-input multiple-output (MIMO), massive MIMO system with tens or even hundreds of antennas is able to give better performance in capacity and spectral efficiency, which is a promising technology for 5G. Considering this, massive MIMO has become a hot research topic all over the world. In this paper, the channel measurements and models of massive MIMO in recent years are summarized. Besides, the related 256 antenna elements with 200 MHz bandwidth at 3.5 GHz proposed by our team, the verification of rationality of the measurement method, and the spatial evolution of clusters in mobile scenario are provided.

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