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20 July 2021, Volume 37 Issue 7

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Comprehensive Review

Outlook on satellite communications network architecture for 6G

Xiaowen WU, Zhenfeng JIAO, Xiang LING, Bing LIU, Lidong ZHU, Lei HAN

2021, 37(7):  1-14.  doi:10.11959/j.issn.1000-0801.2021147

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The future satellite communications network architecture for 6G was analyzed, studied and imagined.Through introducing the current trends of satellite and ground communications integration, with the current research results of 6G network architecture with its vision and requirements, the technical characteristics of 6G network architecture were summarized.The key role of artificial intelligent (AI) in 6G network was deeply explored based on the research and application analysis of AI in the field of communications.Therefore, the idea of AI enabled 6G satellite communications network overall architecture, RAN architecture, core network architecture were proposed, also with step-by-step evolution and implementation.Finally, the enhanced robust mechanism of 6G satellite communication network based on block-chain was also discussed.

Topic: Marine Internet of Things

Architecture and challenges of system models for marine data transmission networks

Shengming JIANG, Lige GE, Yanli XU

2021, 37(7):  16-24.  doi:10.11959/j.issn.1000-0801.2021142

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Marine data transmission networks are different from terrestrials in the following aspects: high dynamics and uncertainties in network boundary, network path and communication and networking resources, heterogeneities of communication media and asymmetric communication performance, complexity of marine communication network resources with limited capabilities and ability, and high complexity and mobility of marine users with low distribution densities etc.In view of the above peculiarities for communication network in the marine space, an SM for marine data transmission network was studied from the aspects of business characteristics, network composition, network characteristics and architecture, and five challenges faced by the architecture were focused on, including adaptability, intelligent networking, transparent transmission, roaming support and secure transmission.

Research and application on key techniques of marine IoT

Fengzhong QU, Hangliang LAI, Jianzhang LIU, Xingbin TU, Yuan JIANG

2021, 37(7):  25-33.  doi:10.11959/j.issn.1000-0801.2021149

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Ocean observation networks with isolated and fragmented sensor data are not able to meet the demands of current ocean monitoring.Marine internet of things (IoT), which has the advantage of low investment cost, low power consumption, and interconnection is the primary research direction in the area of ocean information.An overview of the development and status of ocean observation networks was presented.A new type of marine IoT system architecture was proposed based on the Zhejiang University - Zhairuoshan Experimental Research Observatory (Z₂ERO).It features key marine IoT devices and test platforms, including scientific instrument interface module, hydroacoustic communicators, narrow-band IoT floating balls, seafloor test platforms, and portable acoustic retrievers.Future marine IoT is expected to develop toward miniaturization, intelligence, and diversity of communication methods.With the support of the terrestrial internet, the internet of everything will be achieved through an integrated space-air-ground-sea network.

Architecture of a heterogeneous marine internet of things for intelligent offshore engineering

Zhenhua FU, Jie LI, Fei JI, Hua YU

2021, 37(7):  34-39.  doi:10.11959/j.issn.1000-0801.2021150

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With the development of the offshore engineering towards intelligence and informatization, the safety and environmental monitoring technology is demanding for offshore operating platforms.A heterogeneous marine IoT architecture for the intelligent offshore engineering was proposed.The network was based on underwater acoustic communication technology, marine radio wireless communication, intelligent gateway and cloud platform to realize remote and online monitoring offshore engineering and platforms.The main modules, and some of the key technologies and challenges involvedin the network were introduced.The network architecture can provide a reference for the realization of an intelligent offshore engineering equipment and platforms.

Marine survey unmanned surface vessel:platform design and application

Weiping WANG, Xi HE, Chao DONG, Bing ZHENG, Xue LI

2021, 37(7):  40-47.  doi:10.11959/j.issn.1000-0801.2021146

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Marine survey unmanned surface vessel (USV) has a wide range of applications.However, the attitude of USV is easily affected by wind, waves, currents and floating debris, which may cause structural damage or low precision observation.Double hull and wide deck platform of unmanned surface vessed was designed, and the transducer of multi-beam echo sounder was installed on the lifting mechanism.These designs improved the sailing attitude of the platform, the safety of the transducer and the accuracy of the observed data.In 2020, this USV was participated in the dike-inspection mission of Jiangxi’s emergency flood relief.It successfully inspected the sediment environment of 14 km dike, affected by the unfavorable working conditions like rapid water flow, turbid water and floating garbage.Four risks were located, which provided important data support for the anti-flood campaign.

Design and implementation of unmanned surface vessel long-distance communication system

Xue LI, Haiju HU, Weiping WANG, Yankun CHEN, Bing ZHENG, Chao DONG

2021, 37(7):  48-56.  doi:10.11959/j.issn.1000-0801.2021141

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Unmanned surface vessel (USV) long-distance communication has important use in marine survey operations.The design and equipment development of USV long-distance communication system were carried out from both shore-side communication equipment and boat-mounted communication equipment, and the broadband and narrowband tests of the communication system were carried out in Wanshan and Yellow Sea with the assistance of tethered UAV to conduct communication range test for the whole system.The test results show that when the shore-side communication equipment is raised 129 m, the broadband communication can reach 45 km, when the shore-side communication equipment is raised 180 m, the narrowband communication can reach 50 km, and the communication quality is stable and reliable, meeting the long-distance communication needs of USV.

Research and Development

Stability optimization of dynamic migration algorithm for Post-Copy of virtual machine based on KVM

Shuangxi CHEN, Ruoyan ZHAO, Hui LIU, Chunming WU, Wei RUAN

2021, 37(7):  57-66.  doi:10.11959/j.issn.1000-0801.2021145

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The dynamic migration technology of virtual machine provides a strong support for the resource scheduling of virtualization system.As one of the two core algorithms of virtual machine dynamic migration, Post-Copy algorithm has been a hot issue for scholars at home and abroad for its advantages of stable migration time and short migration downtime.The fault tolerance mechanism of virtual machine, the connection between the transfer mode of memory page and the page missing error during the migration process, and the source code of QEMU-KVM platform were studied.A fault tolerant method based on transaction synchronization was proposed to improve the stability of the Post-Copy migration algorithm.The experimental results show that the proposed algorithm can ensure the fast repair of deep end virtual machine failure, target virtual machine failure and network fault during the migration process, and solve the stability problem at a small cost.The method proposed effectively improves the stability of the Post-Copy migration algorithm, and provides reference for the future optimization research direction.

A novel low-complexity two-tier group antenna selection algorithm

Peichang ZHANG, Wannian AN, Shida ZHONG, Lei HUANG, Chunsheng ZHUANG, Wei ZHANG

2021, 37(7):  67-76.  doi:10.11959/j.issn.1000-0801.2021111

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Aiming at the high complexity of the end-to-end massive MIMO systems in flat correlated Rayleigh fading channel environments, a low-complexity two-tier group antenna selection algorithm based on discrete cuckoo search was proposed.The algorithm firstly grouped large-scale antenna arrays based on the correlation of antenna channels, and then used a new two-tier algorithm to optimize antenna selection for the grouped antenna sets.The first layer of the new two-tier algorithm was the internal selection of each group of antennas based on discrete cuckoo search, and the second layer was the final selection of all antennas selected by the first layer using discrete cuckoo search.The novel antenna selection algorithm could effectively reduce the complexity of large-scale MIMO systems.The simulation results verify that the antenna selection algorithm can obtain the capacity performance close to the optimal selection method and better BER performance with lower selection complexity under the flat correlated Rayleigh fading channel environments.

Persistent homology based topological analysis on the gestalt patterns during human brain cognition process

Zaisheng LIU, Fei NI, Rongpeng LI, Honggang ZHANG, Chang LIU, Jiefang ZHANG, Songyun XIE

2021, 37(7):  77-85.  doi:10.11959/j.issn.1000-0801.2021124

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The integrated development of information communication technology and neuroscience heralds the possibility and great potential of brain-to-brain wireless communication(B2BC).The physiologically meaningful features of brain responses were extracted to different contour and shape in images in Gestalt cognitive tests by combining persistent homology analysis with electroencephalogram (EEG).The experimental results show that more brain regions in the frontal lobe were involved when the subject perceives the random and disordered combination of images compared to the ordered Gestalt images.Meanwhile, the persistence entropy of EEG data evoked by random sequence diagram (RSD) was observed to be significantly different from that by the ordered Gestalt images(GST) in several frequency bands, which indicated that human cognition of shapes and contours, such as a preliminary advanced cognition process, could be separated to some extent through topological analysis.This method can digitize the neural signals while preserving the whole and local features of the original signals.In general, the cognitively related neural correlates by persistent homology features of EEG signal are revaluated and quantified, which provides an approach to realize the digitization of neural signals in brain-to-brain wireless communication.

Application of 5G in railway smart stations

Ruifeng CHEN, Jun LI, Chunjie XU, Qingbo CHENG, Xiaojun LV

2021, 37(7):  86-95.  doi:10.11959/j.issn.1000-0801.2021117

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Accelerating the 5G “new infrastructure” strategy has become the inevitable development trend of railway smart stations.Firstly, state-of-the-art of relevant business of railway smart stations in China was analyzed.Afterwards, the application requirements of 5G communication in railway smart stations were outlined, and then 5G communication network architecture of railway smart stations was constructed based on cloud edge collaboration.Finally, the application modes of railway smart stations based on 5G communication and cloud edge collaboration were respectively proposed for passenger travel service, station operating organization, security guarantee and green energy saving.The application of railway smart stations based on 5G communication can promote the transformation and upgrading of stations, enhance the quality of passenger service, improve passenger travel experience, and increase the efficiency of passenger transport operating organization.

Face recognition algorithm based on attractive local second gradient contours

Xueyi YE, Dingwei QIAN, Na YING, Tao WANG

2021, 37(7):  96-106.  doi:10.11959/j.issn.1000-0801.2021140

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In order to solve the problem that traditional LDP algorithms is difficult to balance the effectiveness of feature extraction and the stability of feature encoding, an attractive local second gradient contours (ALSGC) face feature extraction algorithm was proposed.Firstly, the Kirsch operator was used to calculate the neighborhood edge response image of the face image.Secondly, an attraction descriptor was introduced and the local average gray value and global average gray value of the edge response image and the neighborhood center gray value was combined to complete the local attraction pattern encoding.The entire image was traversed to get the ALSGC face feature map, the ALSGC feature map was divided to blocks and the statistical histograms of different patterns for each block was obtained by calculation.Finally, the statistical histograms of all the blocks were cascaded to generate the corresponding feature vector and support vector machine was used to complete classification and recognition.The proposed algorithm not only overcame the insufficient effectiveness of LBP, LDP, LDN and other algorithms who extract first-gradient features, but also reduced the sensitivity to changes in expression, posture, occlusion, lighting and random noise of methods such as DLDP, CSLDP, GCSLDP who extracting second-gradient features.It better achieved the balance between the effectiveness of feature extraction and the stability of feature encoding, and took into account the recognition rate and robustness.

Research and prospect on economic value evaluation and pricing mechanism of spectrum resources

Jie DONG, Hengzhi LI, Yan CHEN, Wenjuan WANG

2021, 37(7):  107-114.  doi:10.11959/j.issn.1000-0801.2021138

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Firstly, from the perspective of natural resource value, the value composition, timeliness, integrity, structure and sociality of value characteristics and value existence forms of spectrum resources were explained, and the definition and connotation of economic value evaluation and pricing of spectrum resources were given.Finally, the pricing methods of spectrum resources, such as the pricing method based on spectrum fee, the pricing method based on administrative fee, the pricing method based on user’s gross income and the opportunity cost method, and the pricing methods of spectrum resources adopted by some countries were sorted out and analyzed, and some suggestions were put forward to further improve the economic value evaluation and pricing mechanism of spectrum resources in China.

Research and Development

Nowcasting of China’s industrial added value based on electric power big data

Fang PENG, Gaoqun PENG, Yaru QI, Tiantian LIU, Xiaolei ZHOU

2021, 37(7):  115-125.  doi:10.11959/j.issn.1000-0801.2021143

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Industrial added value is an important indicator to measure the operation of the real economy.In order to fully mine the value of power data in the current macroeconomic nowcasting, so as to serve the government policy making, the Bagging and Boosting algorithms in machine learning were applied to nowcast industrial added value based on electric power data as well as traditional statistical data.Firstly, traditional statistical data can significantly improve the forecasting effect of the ARIMA model.Secondly, the nowcasting ability of electric power data depends on the selection of electric power indicators, and the proper electric power index is helpful to predict industrial added value more timely and accurately.Thirdly, the prediction ability of electric power data to the industrial added value in the current period may be lower than that in the future, which means the power data is more likely to be used to predict ahead of time.

Engineering and Application

FlexE slicing technology for STN bearer network to 5G

Yuanyang YIN, Guidong LIN, Guangming YANG, Quan LU, Shuangfeng LAN

2021, 37(7):  126-133.  doi:10.11959/j.issn.1000-0801.2021068

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The development of new network technology injects new vitality into the new generation of communication.In the 5G era, how to build a bearing network with slicing capability has become the top priority of 5G bearing network construction according to the new customized network application fields and requirements.In-depth research and exploration was made from the aspects of FlexE technology architecture and application scenarios, and a comparative analysis was made with FlexE circuit crossing technology.The STN bearer network slice architecture based on IP / MPLS mechanism with FlexE interface technology was conceived.5G STN bearer network was deployed with FlexE and the development direction were proposed.It can meet the requirements of large-scale commercial deployment of 5G STN network slice.

Research on uplink coverage enhancement of 5G network

Yuhua HU, Xinyan WANG, Bei LI

2021, 37(7):  134-141.  doi:10.11959/j.issn.1000-0801.2021148

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The 5G network frequency band is mostly high frequency band, which is rich in bandwidth resources, but the path loss and penetration loss are high, and the uplink coverage is relatively weak.If the low frequency band resources are introduced for uplink transmission, the cooperation of high and low frequency carriers will help to improve the uplink coverage.The link budget and coverage performance of 2.1 GHz and 3.5 GHz bands were analyzed, three uplink coverage enhancement schemes were compared, and the advantages and limitations of carrier aggregation scheme were analyzed.The result shows that carrier aggregation scheme is the optimal solution for 5G network uplink coverage enhancement.

Application scenarios and difficulties in network construction of digital mines in cement industry based on 5G

Huijie ZHAO, Xuezhi ZHANG, Dong XIE

2021, 37(7):  142-147.  doi:10.11959/j.issn.1000-0801.2021098

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The application and development of 5G in the field of cement mining has drawn attention.Cement factories, usually built around limestone mines, in which 5G network shows great value to be used for safe inspection by drones, UAV 3D modeling of mines, unmanned driving and remote control of mining vehicles, of excavators and other mobile services.Firstly, the main business scenarios and network requirements of 5G in cement industry mines was analyzed.Secondly, via the analysis of practical cases and test data of 5G cement mine network deployment, the difficulty of 5G network coverage in mines lies in the poor coverage rate and signal strength of 5G network in limestone mines, which are due to mountain shielding effect mined by hillside terraced fields.Finally, the difficulties of 5G mine network coverage were summarized from the aspects of supporting facilities, planning simulation and environmental dynamic change, and preliminary suggestions were given correspondingly.

5G technology enabling unmanned offshore platform

Rujun XIA

2021, 37(7):  148-154.  doi:10.11959/j.issn.1000-0801.2021144

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The exploration, development and production of offshore oil are characterized by “high risk, high investment and high technology”.Many restrictive factors, such as the inferiority of offshore natural environment, the high risk of oil and gas production, and the demand for communication signal stability, equipment operation reliability and timely emergency support, make it more difficult to realize unmanned offshore platform.Based on the analysis of the status quo, development trend and implementation requirements of unmanned offshore platform, a 5G communication scheme for unmanned offshore platform was proposed.5G network is built between the central platform and the wellhead platform, and the transmission rate, distance, delay and other field tests were carried out.The test results show that 5G communication meets the requirements of high reliability and low delay stable transmission, such as security monitoring, remote control, emergency stop and so on.The scheme has accumulated experience and laid a solid foundation for the construction of an unmanned offshore platform.