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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.  
    Abstract884)      PDF (451KB)(1144)       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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    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
    Abstract1688)      PDF (476KB)(912)       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.  
    Abstract1294)      PDF (640KB)(826)       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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    Cloud Computing: Concept, Model, and Key Technologies
    Kevin Yin
    ZTE Communications    2010, 8 (4): 21-26.  
    Abstract494)      PDF (468KB)(755)       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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    Analysis of Hot Topics in Cloud Computing
    Li Deyi, Chen Guisheng, Zhang Haisu
    ZTE Communications    2010, 8 (4): 1-5.  
    Abstract836)      PDF (521KB)(558)       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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    Signal Detection and Channel Estimation in OTFS
    NAIKOTI Ashwitha, CHOCKALINGAM Ananthanarayanan
    ZTE Communications    2021, 19 (4): 16-33.   DOI: 10.12142/ZTECOM.202104003
    Abstract366)   HTML10)    PDF (2749KB)(557)       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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    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
    Abstract524)   HTML205)    PDF (1032KB)(507)       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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    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
    Abstract188)   HTML74)    PDF (3130KB)(472)       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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    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
    Abstract202)   HTML5)    PDF (1356KB)(436)       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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    Kinetic Energy Harvesting Toward Battery-Free IoT: Fundamentals, Co-Design Necessity and Prospects
    LIANG Junrui, LI Xin, YANG Hailiang
    ZTE Communications    2021, 19 (1): 48-60.   DOI: 10.12142/ZTECOM.202101007
    Abstract128)   HTML9)    PDF (1567KB)(436)       Save

    Energy harvesting (EH) technology is developed with the purpose of harnessing ambient energy in different physical forms. Although the available ambient energy is usually tiny, not comparable to the centralized power generation, it brings out the convenience of on-site power generation by drawing energy from local sources, which meets the emerging power demand of long-lasting, extensively-deployed, and maintenance-free Internet of Things (IoT). Kinetic energy harvesting (KEH) is one of the most promising EH solutions toward the realization of battery-free IoT. The KEH-based battery-free IoT can be extensively deployed in the smart home, smart building, and smart city scenarios, enabling perceptivity, intelligence, and connectivity in many infrastructures. This paper gives a brief introduction to the configurations and basic principles of practical KEH-IoT systems, including their mechanical, electrical, and computing parts. Although there are already a few commercial products in some specific application markets, the understanding and practice in the co-design and optimization of a single KEH-IoT device are far from mature, let alone the conceived multiagent energy-autonomous intelligent systems. Future research and development of the KEH-IoT system beckons for more exchange and collaboration among mechanical, electrical, and computer engineers toward general design guidelines to cope with these interdisciplinary engineering problems.

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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
    Abstract496)   HTML115)    PDF (494KB)(433)       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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    Reliable and Privacy-Preserving Federated Learning with Anomalous Users
    ZHANG Weiting, LIANG Haotian, XU Yuhua, ZHANG Chuan
    ZTE Communications    2023, 21 (1): 15-24.   DOI: 10.12142/ZTECOM.202301003
    Abstract69)   HTML11)    PDF (1351KB)(393)       Save

    Recently, various privacy-preserving schemes have been proposed to resolve privacy issues in federated learning (FL). However, most of them ignore the fact that anomalous users holding low-quality data may reduce the accuracy of trained models. Although some existing works manage to solve this problem, they either lack privacy protection for users’ sensitive information or introduce a two-cloud model that is difficult to find in reality. A reliable and privacy-preserving FL scheme named reliable and privacy-preserving federated learning (RPPFL) based on a single-cloud model is proposed. Specifically, inspired by the truth discovery technique, we design an approach to identify the user’s reliability and thereby decrease the impact of anomalous users. In addition, an additively homomorphic cryptosystem is utilized to provide comprehensive privacy preservation (user’s local gradient privacy and reliability privacy). We give rigorous theoretical analysis to show the security of RPPFL. Based on open datasets, we conduct extensive experiments to demonstrate that RPPEL compares favorably with existing works in terms of efficiency and accuracy.

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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
    Abstract260)   HTML200)    PDF (368KB)(357)       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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    Recent Progress in Research and Development of Reconfigurable Intelligent Surface
    YUAN Yifei, GU Qi, WANG Anna, WU Dan, LI Ya
    ZTE Communications    2022, 20 (1): 3-13.   DOI: 10.12142/ZTECOM.202201002
    Abstract148)   HTML24)    PDF (2269KB)(350)       Save

    We aim to provide a comprehensive overview of the progress in research and development of the reconfigurable intelligent surface (RIS) over the last 2–3 years in this paper, especially when the RIS is used as relays in next-generation mobile networks. Major areas of research in academia are outlined, including fundamental performance, channel estimation, joint optimization with antenna precoding at base stations, propagation channel modeling and meta-material devices of RIS elements. Development in industry is surveyed from the aspects of performance potentials and issues, realistic joint optimization algorithms, control mechanisms, field trials and related activities in standardization development organizations (SDOs). Our views on how to carry out the engineering-aspect study on RIS for 6G systems are also presented, which cover the realistic performance, the comparison with other topological improvements, approaches for channel modeling, factors for designing control mechanisms and the timeline for RIS standardization.

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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
    Abstract311)   HTML178)    PDF (324KB)(338)       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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    A Survey on Low Complexity Detectors for OTFS Systems
    ZHANG Zhengquan, LIU Heng, WANG Qianli, FAN Pingzhi
    ZTE Communications    2021, 19 (4): 3-15.   DOI: 10.12142/ZTECOM.202104002
    Abstract173)   HTML11)    PDF (1427KB)(332)       Save

    The newly emerging orthogonal time frequency space (OTFS) modulation can obtain delay-Doppler diversity gain to significantly improve the system performance in high mobility wireless communication scenarios such as vehicle-to-everything (V2X), high-speed railway and unmanned aerial vehicles (UAV), by employing inverse symplectic finite Fourier transform (ISFFT) and symplectic finite Fourier transform (SFFT). However, OTFS modulation will dramatically increase system complexity, especially at the receiver side. Thus, designing low complexity OTFS receiver is a key issue for OTFS modulation to be adopted by new-generation wireless communication systems. In this paper, we review low complexity OTFS detectors and provide some insights on future researches. We firstly present the OTFS system model and basic principles, followed by an overview of OTFS detector structures, classifications and comparative discussion. We also survey the principles of OTFS detection algorithms. Furthermore, we discuss the design of hybrid OTFS and orthogonal frequency division multiplexing (OFDM) detectors in single user and multi-user multi-waveform communication systems. Finally, we address the main challenges in designing low complexity OTFS detectors and identify some future research directions.

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    Cooperative Intelligence for Autonomous Driving
    CHENG Xiang, DUAN Dongliang, YANG Liuqing, ZHENG Nanning
    ZTE Communications    2019, 17 (2): 44-50.   DOI: 10.12142/ZTECOM.201902007
    Abstract169)   HTML24)    PDF (983KB)(324)       Save

    Autonomous driving is an emerging technology attracting interests from various sectors in recent years. Most of existing work treats autonomous vehicles as isolated individuals and has focused on developing separate intelligent modules. In this paper, we attempt to exploit the connectivity among vehicles and propose a systematic framework to develop autonomous driving techniques. We first introduce a general hierarchical information fusion framework for cooperative sensing to obtain global situational awareness for vehicles. Following this, a cooperative intelligence framework is proposed for autonomous driving systems. This general framework can guide the development of data collection, sharing and processing strategies to realize different intelligent functions in autonomous driving.

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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
    Abstract199)   HTML23)    PDF (965KB)(314)       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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    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
    Abstract480)   HTML120)    PDF (519KB)(306)       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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    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
    Abstract282)      PDF (408KB)(303)       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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    Cloud Computing(4)
    Wang Bai, Xu Liutong
    ZTE Communications    2010, 8 (4): 57-60.  
    Abstract53)      PDF (408KB)(301)       Save
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    Emotion Analysis on Social Big Data
    REN Fuji, Kazuyuki Matsumoto
    ZTE Communications    2017, 15 (S2): 30-37.   DOI: 10.3969/j.issn.1673-5188.2017.S2.005
    Abstract164)   HTML176)    PDF (677KB)(294)       Save

    In this paper, we describe a method of emotion analysis on social big data. Social big data means text data that is emerging on Internet social networking services.We collect multilingual web corpora and annotated emotion tags to these corpora for the purpose of emotion analysis. Because these data are constructed by manual annotation, their quality is high but their quantity is low. If we create an emotion analysis model based on this corpus with high quality and use the model for the analysis of social big data, we might be able to statistically analyze emotional sensesand behavior of the people in Internet communications, which we could not know before. In this paper, we create an emotion analysis model that integrate the high-quality emotion corpus and the automatic-constructed corpus that we created in our past studies, and then analyze a large-scale corpus consisting of Twitter tweets based on the model. As the result of time-series analysis on the large-scale corpus and the result of model evaluation, we show the effectiveness of our proposed method.

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    Cloud Storage Technology and Its Applications
    Zhou Ke, Wang Hua, Li Chunhua
    ZTE Communications    2010, 8 (4): 27-30.  
    Abstract433)      PDF (521KB)(288)       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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    Dual‑Polarized RIS‑Based STBC Transmission with Polarization Coupling Analysis
    ZHOU Mingyong, CHEN Xiangyu, TANG Wankai, KE Jun Chen, JIN Shi, CHENG Qiang, CUI Tie Jun
    ZTE Communications    2022, 20 (1): 63-75.   DOI: 10.12142/ZTECOM.202201009
    Abstract166)   HTML21)    PDF (1409KB)(284)       Save

    The rapid development of the reconfigurable intelligent surface (RIS) technology has given rise to a new paradigm of wireless transmitters. At present, most research works on RIS-based transmitters focus on single-polarized RISs. In this paper, we propose a dual-polarized RIS-based transmitter, which realizes 4-transmit space-time block coding (STBC) transmission by properly partitioning RIS’s unit cells and utilizing the degree of freedom of polarization. The proposed scheme is evaluated through a prototype system that utilizes a fabricated dual-polarized phase-adjustable RIS. In particular, the polarization coupling phenomenon in each unit cell of the employed dual-polarized RIS is modeled and analyzed. The experimental results are in good agreement with the theoretical modeling and analysis results, and an initial research effort is made on characterizing the polarization coupling property in the dual-polarized RIS.

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    Recent Developments of Transmissive Reconfigurable Intelligent Surfaces: A Review
    TANG Junwen, XU Shenheng, YANG Fan, LI Maokun
    ZTE Communications    2022, 20 (1): 21-27.   DOI: 10.12142/ZTECOM.202201004
    Abstract177)   HTML15)    PDF (1869KB)(282)       Save

    Reconfigurable intelligent surface (RIS) is considered as one of the key technologies for the next-generation mobile communication systems. The transmissive RIS is able to achieve dynamic beamforming capability while transmitting an in-band RF signal through its aperture, and has promising prospects in various practical application scenarios. This paper reviews some of the latest developments of the transmissive RIS. The approaches for transmissive RIS designs are classified and described briefly. Numerous designs with different phase resolutions, such as 1-bit, 2-bit or continuous 360° phase shifts, are presented, with detailed discussions on their operating mechanisms and transmission performances. The design solutions for various transmissive RIS elements are summarized and compared.

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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
    Abstract175)   HTML128)    PDF (360KB)(271)       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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    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
    Abstract201)   HTML49)    PDF (1219KB)(270)       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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    OTFS Enabled NOMA for MMTC Systems over LEO Satellite
    MA Yiyan, MA Guoyu, WANG Ning, ZHONG Zhangdui, AI Bo
    ZTE Communications    2021, 19 (4): 63-70.   DOI: 10.12142/ZTECOM.202104007
    Abstract110)   HTML6)    PDF (528KB)(265)       Save

    As a complement of terrestrial networks, non-terrestrial networks (NTN) have advantages of wide-area coverage and service continuity. The NTN is potential to play an important role in the 5G new radio (NR) and beyond. To enable the massive machine type communications (mMTC), the low earth orbit (LEO) satellite is preferred due to its lower transmission delay and path loss. However, the LEO satellite may generate notable Doppler shifts to degrade the system performance. Recently, orthogonal time frequency space (OTFS) modulation has been proposed. It provides the opportunity to allocate delay Doppler (DD) domain resources, which is promising for mitigating the effect of high mobility. Besides, as the LEO satellite constellation systems such as Starlink are thriving, the space spectrum resources have become increasingly scarce. Therefore, non-orthogonal multiple access (NOMA) is considered as a candidate technology to realize mMTC with limited spectrum resources. In this paper, the application of OTFS enabled NOMA for mMTC over the LEO satellite is investigated. The LEO satellite based mMTC system and the OTFS-NOMA schemes are described. Subsequently, the challenges of applying OTFS and NOMA into LEO satellite mMTC systems are discussed. Finally, the potential technologies for the systems are investigated.

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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
    Abstract278)      PDF (564KB)(263)       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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    Boundary Data Augmentation for Offline Reinforcement Learning
    SHEN Jiahao, JIANG Ke, TAN Xiaoyang
    ZTE Communications    2023, 21 (3): 29-36.   DOI: 10.12142/ZTECOM.202303005
    Abstract175)   HTML19)    PDF (1865KB)(260)       Save

    Offline reinforcement learning (ORL) aims to learn a rational agent purely from behavior data without any online interaction. One of the major challenges encountered in ORL is the problem of distribution shift, i.e., the mismatch between the knowledge of the learned policy and the reality of the underlying environment. Recent works usually handle this in a too pessimistic manner to avoid out-of-distribution (OOD) queries as much as possible, but this can influence the robustness of the agents at unseen states. In this paper, we propose a simple but effective method to address this issue. The key idea of our method is to enhance the robustness of the new policy learned offline by weakening its confidence in highly uncertain regions, and we propose to find those regions by simulating them with modified Generative Adversarial Nets (GAN) such that the generated data not only follow the same distribution with the old experience but are very difficult to deal with by themselves, with regard to the behavior policy or some other reference policy. We then use this information to regularize the ORL algorithm to penalize the overconfidence behavior in these regions. Extensive experiments on several publicly available offline RL benchmarks demonstrate the feasibility and effectiveness of the proposed method.

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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
    Abstract176)   HTML71)    PDF (490KB)(252)       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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    Cloud Computing, Fog Computing, and Dew Computing
    PAN Yi, LUO Guangchun
    ZTE Communications    2017, 15 (4): 1-2.  
    Abstract172)   HTML29)    PDF (203KB)(251)       Save
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    Orthogonal Time Frequency Space Modulation in Multiple-Antenna Systems
    WANG Dong, WANG Fanggang, LI Xiran, YUAN Pu, JIANG Dajie
    ZTE Communications    2021, 19 (4): 71-78.   DOI: 10.12142/ZTECOM.202104008
    Abstract68)   HTML3)    PDF (1729KB)(244)       Save

    The application of the orthogonal time frequency space (OTFS) modulation in multiple-antenna systems is investigated. The diversity and/or the multiplexing gain can be achieved by deploying various multiple-antenna techniques, and thus the reliability and/or the spectral efficiency are improved correspondingly. We provide two classes of OTFS-based multiple-antenna approaches for both the open-loop and the closed-loop systems. Specifically, in the open-loop system, a transmitting diversity approach, which resembles the space-time coding technique, is proposed by allocating the information symbols appropriately in the delay-Doppler domain. In the closed-loop system, we adopt the Tomlinson-Harashima precoding in our derived delay-Doppler equivalent transmission model. Numerical evaluations demonstrate the advantages of applying the multiple-antenna techniques to the OTFS. At last, several challenges and opportunities are presented.

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    Editorial: Special Topic on OTFS Modulation for 6G and Future High Mobility Communications
    YUAN Jinhong, FAN Pingzhi, BAI Baoming, AI Bo
    ZTE Communications    2021, 19 (4): 1-2.   DOI: 10.12142/ZTECOM.202104001
    Abstract56)   HTML11)    PDF (365KB)(244)       Save
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    Signal Processing Techniques for 5G: An Overview
    Fa-Long Luo
    ZTE Communications    2015, 13 (1): 20-27.   DOI: 10.3969/j.issn.1673-5188.2015.01.003
    Abstract208)      PDF (401KB)(241)       Save
    This paper gives an outline of the algorithms and implementation of the main signal processing techniques being developed for 5G wireless communication. The first part contains a review and comparison of six orthogonal and non-orthogonal waveform-generation and modulation schemes: generalized frequency-division multiplexing (GFDM), filter-bank multicarrier (FBMC), universal filtered multicarrier (UFMC), bi-orthogonal frequency-division multiplexing (BFDM), sparse-code multiple-access (SCMA), and non-orthogo-nal multiple access (NOMA). The second part discusses spatial signal processing algorithms and implementations for massive multiple-input multiple-output (massive-MIMO), 3D beamforming and diversity, and orbital angular momentum (OAM) based multi-plexing. The last part gives an overview of signal processing aspects of other emerging techniques in 5G, such as millimeter-wave, cloud radio access networks, full duplex mode, and digital radio-frequency processing.
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    Multimodal Emotion Recognition with Transfer Learning of Deep Neural Network
    HUANG Jian, LI Ya, TAO Jianhua, YI Jiangyan
    ZTE Communications    2017, 15 (S2): 23-29.   DOI: 10.3969/j.issn.1673-5188.2017.S2.004
    Abstract141)   HTML65)    PDF (418KB)(241)       Save

    Due to the lack of large-scale emotion databases, it is hard to obtain comparable improvement in multimodal emotion recognition of the deep neural network by deep learning, which has made great progress in other areas. We use transfer learning to improve its performance with pre-trained models on large-scale data. Audio is encoded using deep speech recognition networks with 500 hours’ speech and video is encoded using convolutional neural networks with over 110,000 images. The extracted audio and visual features are fed into Long Short-Term Memory to train models respectively. Logistic regression and ensemble method are performed in decision level fusion. The experiment results indicate that 1) audio features extracted from deep speech recognition networks achieve better performance than handcrafted audio features; 2) the visual emotion recognition obtains better performance than audio emotion recognition; 3) the ensemble method gets better performance than logistic regression and prior knowledge from micro-F1 value further improves the performance and robustness, achieving accuracy of 67.00% for “happy”, 54.90% for “angry”, and 51.69% for “sad”.

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    A Survey on Cloud Security
    WU Chunming, LIU Qianjun, LI Yuwei, CHENG Qiumei, ZHOU Haifeng
    ZTE Communications    2017, 15 (2): 42-47.   DOI: 10.3969/j.issn.1673-5188.2017.02.006
    Abstract153)   HTML23)    PDF (430KB)(235)       Save

    Cloud computing system packages infrastructures, applications and other resources as services, and delivers the services to market in an elastic and fast way. The significant advantages of cloud computing, e.g., scalability, elasticity, and pay-per-use, bring it considerable commercial values. Nevertheless, owing to the new application scenario, e.g., multi-tenant, cloud computing is encountering potential security risks. This paper reviews the state-of-art research in cloud security. According to the attack levels, it analyzes four kinds of attacks in the cloud, i.e., network-based attacks, VM-based attacks, storage-based attacks, and application-based attacks. The countermeasures and corresponding techniques are then introduced. Furthermore, this paper also discusses an innovative and promising solution for cloud security by dynamically changing system configuration.

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    SHVC, the Scalable Extensions of HEVC, and Its Applications
    Yan Ye, Yong He, YeKui Wang, Hendry
    ZTE Communications    2016, 14 (1): 24-41.   DOI: 10.3969/j.issn.1673-5188.2016.01.004
    Abstract148)      PDF (450KB)(227)       Save
    This paper discusses SHVC, the scalable extension of the High Efficiency Video Coding (HEVC) standard, and its applications in broadcasting and wireless broadband multimedia services. SHVC was published as part of the second version of the HEVC specification in 2014. Since its publication, SHVC has been evaluated by application standards development organizations (SDOs) for its potential benefits in video applications, such as terrestrial and mobile broadcasting in ATSC 3.0, as well as a variety of 3GPP mul?timedia services, including multi-party multi-stream video conferencing (MMVC), multimedia broadcast/multicast service (MBMS), and dynamic adaptive streaming over HTTP (DASH). This paper provides a brief overview of SHVC and the performance and complexity analyses of using SHVC in these video applications.
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    Next Generation Mobile Video Networking
    HWANG Jenq-Neng, WEN Yonggang
    ZTE Communications    2018, 16 (3): 1-2.   DOI: 10.19729/j.cnki.1673-5188.2018.03.001
    Abstract126)   HTML87)    PDF (211KB)(224)       Save
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    100G Ethernet Technology and Applications
    Zhang Yuanwang
    ZTE Communications    2009, 7 (4): 54-57.  
    Abstract143)      PDF (297KB)(223)       Save
    The increasing requirements for bandwidth drive the 100G Ethernet into use as quickly as possible. The major technologies supporting 100G Ethernet interface include the physical layer channel convergence technology, multi-fiber channel and Wavelength Division Multiplexing (WDM ) technology. The key technology for high-speed optical devices at the interface requires a breakthrough. The demands driven by the increase of interface rate require better packet processing and storage, system switching, and backplane technology. In addition, in the network, the transport problem of the new interface should be solved, including defining transport standards and pushing the development of key transport technologies. As far as the cost and requirements are concerned, the commercial application of 100G Ethernet is viable in Metropolitan Area Networks (MANs ).
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