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    20 February 2024, Volume 40 Issue 2
    Review
    Analysis and suggestions on inter-satellite laser communication of satellite Internet
    Shanzhi CHEN, Zhiwen FAN, Jiade JIN, Yun CAO
    2024, 40(2):  1-10.  doi:10.11959/j.issn.1000-0801.2024033
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    Satellite communication and terrestrial mobile communication have strong complemented co-benefits.Satellite Internet is the hot spot supporting current industrial development and an important part of the future 6G network.Global coverage requires interstellar networking, but inter-satellite communication bandwidth requirements and the instability brought by the free space channel pose new challenges to the space bearer network.Inter-satellite communication technologies and link interface technologies were compared and analyzed.An optical transport network (OTN) carrier network solution based on inter-satellite laser was proposed, which could fully leverage the advantages of the maturities and the economies of the scaled ground optical communication.It constructs a satellite-terrestrial integrated network with strong cost-efectivity, compatibility, and scalability.Finally, the technological directions and evolutions of the inter-satellite laser communication were discussed, and suggestions for industrial development in China were proposed.

    Research and Development
    Environment-aware based access point deployment optimization for cell-free massive MIMO system
    Jing JIANG, Yongqiang LIU, Fengyang YAN, Sha TAO, Sutthiphan WORAKRIN
    2024, 40(2):  11-21.  doi:10.11959/j.issn.1000-0801.2024022
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    Cell-free massive multiple-input multiple-output (MIMO) systems deploy a large number of access point (AP) across the coverage area which can provide uniform high-rate services to users.However, the quality of coverage would be affected by path loss, shadow fading scatters, and environmental occlusions around the randomly placed AP in conventional cell-free massive MIMO systems that do not consider their impact.Considering the impact of actual wireless propagation environments, an AP deployment scheme was proposed to acquire uniform and consistent coverage.Firstly, a hybrid probabilistic path loss model was utilized to characterize various wireless propagation environments.Then, the AP deployment optimization problem was solved with the objective of maximizing the average throughput.Finally, the problem was transformed into a Markov game process and solved by the multi-agent deep deterministic policy gradient (MADDPG) algorithm.The simulation results demonstrate that the proposed scheme can provide more uniform coverage in complex environments and serve users with reliable and consistent service compared to random AP deployment and existing AP deployment methods.

    EDWF-MTTF-based heuristic scheduling algorithm in time-sensitive networks
    Chuanhuang LI, Junhu LIAO, Jiadong XUAN, Qi XU, Huifeng ZHANG, Jun ZHU, Tao ZOU, Ruyun ZHANG
    2024, 40(2):  22-37.  doi:10.11959/j.issn.1000-0801.2024009
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    With the rapid integration and development of industrial control and information networks, time-sensitive networks based on ethernet have received widespread attention.In these networks, time-triggered communication scheduling is adopted to ensure the determinacy of data transmission.However, existing scheduling algorithms have struggled to rapidly calculate the scheduling tables for large-scale periodic traffic.Therefore, a heuristic scheduling algorithm based on the earliest deadline with weight first-maximum transfer time first was designed.This algorithm, by flexibly adapting traffic sorting weights and enhancing backtracking methods, could resolve the scheduling issues of large-scale traffic in industrial automation scenarios in a relatively short time.Experimental results show that compared to the classic integer linear programming method, the earliest deadline with weight first-maximum transfer time first heuristic scheduling algorithm is able to calculate a more optimal solution for the scheduling table of large-scale periodic traffic more swiftly.

    Energy efficiency optimization under joint transmittion power and channel allocation for cellular network
    Huibin XU
    2024, 40(2):  38-46.  doi:10.11959/j.issn.1000-0801.2024004
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    In order to solve problem of low-energy efficiency caused by device-to-device (D2D) interference in hybrid D2D cellular network, energy efficiency improvement based on joint power control and channel allocation (EEPC) algorithm was proposed to improve the energy efficiency.The optimization problem of maximizing energy efficiency was established with the constraint of ensuring the minimum rate of D2D users and cellular users.By using block coordinate descent method, the optimization problem was transformed into two sub-problems of channel allocation and power control, which were solved by Q-learning algorithm, Dinkelbach algorithm and majorization-minimization (MM) respectively.The greedy search factor in Q-learning algorithm was improved, and a dynamic search factor was used to balance the relationship between exploration and exploitation.Performance analysis shows that the proposed EEPC algorithm improves the energy efficiency of the system.

    Optimal active defense decision model of wireless communication network under APT attack
    Meng MENG, Danni WANG, Jun LYU, Fuliang ZHANG
    2024, 40(2):  47-55.  doi:10.11959/j.issn.1000-0801.2024020
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    The optimal active defense decision can ensure the security and stability of wireless communication networks.In order to improve the defense effectiveness of wireless communication networks, an optimal active defense decision model for wireless communication networks under APT attacks was proposed.Wireless communication network logs were associated, a set of APT attack objects were constructed, the absolute compatibility of APT attack events was calculated through feedback compatibility coefficients, and APT attack behaviors were predicted.Based on the channel bandwidth of APT attack sources on wireless communication networks, the location of the wireless communication network being attacked by APT was obtained, and the weight coefficients of wireless communication network nodes were used to extract the APT attack characteristics of the wireless communication network.Using the attack and defense diagram, the degree of damage caused by APT attacks to wireless communication networks was calculated.By defining the security status of wireless communication networks, an optimal active defense decision model for wireless communication networks was constructed.The experimental results show that the proposed model can increase the packet rejection rate and throughput of attack packets to over 90% and 16 000 bit/s respectively when defending against APT attacks in wireless communication networks, with lower time delay and better defense effectiveness.

    Research on interference avoidance detection method for wireless access system
    Jian GONG, Xu SHI, Qiaochun XU
    2024, 40(2):  56-62.  doi:10.11959/j.issn.1000-0801.2024023
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    The types of interference avoidance mechanisms adopted by wireless access systems to realize spectrum sharing and compatibility were introduced, and the specific detection methods such as channel occupancy time, idle channel evaluation, idle channel evaluation time cumulative probability distribution statistics, determination of interference signal detection threshold, silent period duration and equivalent utility were explained.The problems in the actual device detection system were highlighted, and new effective channel occupancy time and idle channel evaluation algorithms and the determination process were given.

    A method for synthetic speech detection using local phase quantization
    Jia XU, Zhihua JIAN, Honghui JIN, Man YANG
    2024, 40(2):  63-71.  doi:10.11959/j.issn.1000-0801.2024024
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    Due to the convenience of speech synthesis, synthesized disguised speech poses a great threat to the security of speaker verification systems.In order to further enhance the ability of detecting the camouflage to the speaker verification system, a method of synthetic speech detection was put forward using the information in spectral domain of the synthetic speech spectrogram.The method employed the local phase quantization (LPQ) algorithm to describe frequency domain information in the speech spectrogram.Firstly, the spectrogram was divided into several sub-blocks, and then the LPQ was performed on each sub-block.After the histogram statistical analysis, the LPQ feature vector was obtained and used as the input feature of the random forest classifier to realize the synthetic speech detection.The experimental results demonstrate that the proposed method further reduces tandem detection cost function (t-DCF) and has better generalization ability.

    A hybrid model for smart grid theft detection based on deep learning
    Yinling LIAO, Jincan LI, Bing WANG, Jun ZHANG, Yaoyuan LIANG
    2024, 40(2):  72-82.  doi:10.11959/j.issn.1000-0801.2024027
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    A hybrid deep learning model was proposed to effectively detect electricity theft in smart grids.The hybrid model employed a deep learning convolutional neural network (AlexNet) to tackle the curse of dimensionality, significantly enhancing data processing accuracy and efficiency.It further improved classification accuracy by differentiating between normal and abnormal electricity usage using adaptive boosting (AdaBoost).To resolve the issue of class imbalance, undersampling techniques were utilized, ensuring balanced performance across various data classes.Additionally, the artificial bee colony algorithm was used to optimize hyperparameters for both AdaBoost and AlexNet, effectively boosting overall model performance.The effectiveness of this hybrid model was evaluated using real smart meter datasets from an electricity company.Compared to similar models, this hybrid model achieves accuracy, precision, recall, F1-score, Matthews correlation coefficient (MCC), and area under the curve-receiver operating characteristic curve (AUC-ROC) scores of 88%, 86%, 84%, 85%, 78%, and 91%, respectively.The proposed model not only increases the accuracy of electricity usage monitoring, but also offers a new perspective for intelligent analysis in power systems.

    Analysis and research on propagation field strength characteristics of non-line-of-sight signal
    Fengxun GONG, Ying ZHANG
    2024, 40(2):  83-95.  doi:10.11959/j.issn.1000-0801.2024019
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    In order to explore the diffraction loss caused by non-line-of-sight (NLOS ) propagation caused by obstacles in the airport communication path, the attenuation characteristics of signal field were studied.Firstly, based on the influence of different terrain environments on signal propagation in ITU-R P.1546, a combined signal field strength model was constructed with Deygout model.Secondly, according to the number of obstacles, the propagation characteristics of the received field strength varying with the height of obstacles were analyzed.The simulation results show that the higher the single obstacle is, the larger the Fresnel zone occupying 0.6F1 is and the smaller the field strength is.In the dual obstacle path, the obstacle with increased height goes through the process of changing from secondary to main obstacle until only the main obstacle is left, so that the field strength gradually decreases.Thirdly, the relationship between secondary obstacle height and 0.6F1 Fresnel zone was analyzed for field strength rise.Finally, the minimum threshold of the covered field strength was adjusted to determine whether the receiving device was blocked by obstacles and the signal was shielded.The above research results can provide a reference for simulating the distribution of obstacles in various airport scenarios in the future, and predicting whether the receiver is interfered by obstacles or affects the field intensity coverage.

    Research on task offloading algorithm of mobile edge computing based on deep reinforcement learning in SDCN
    Shouhua JIANG, Yiwu WANG
    2024, 40(2):  96-106.  doi:10.11959/j.issn.1000-0801.2024025
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    With the continuous development of network technology, the network topology distributed network control mode based on Fat-Tree gradually reveals its limitations.Software-defined data center network (SDCN) technology, as an improved technology of Fat-Tree network topology, has attracted more and more researchers’ attention.Firstly, an edge computing architecture in SDCN and a task offloading model based on the three-layer service architecture of the mobile edge computing (MEC) platform were built, combined with the actual application scenarios of the MEC platform.Through the same strategy experience playback and entropy regularization, the traditional deep Q-leaning network (DQN) algorithm was improved, and the task offloading strategy of MEC platform was optimized.An improved DQN algorithm based on same strategy empirical playback and entropy regularization (RSS2E-DQN) was compared with three other algorithms in load balancing, energy consumption, delay and network usage.It is verified that the improved algorithm has better performance in the above four aspects.

    Security access permission authentication simulation of multi-source network big data based on blockchain
    Bin LI, Hui HE, Zhongying ZHAO, Jingwei GUO
    2024, 40(2):  107-115.  doi:10.11959/j.issn.1000-0801.2024021
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    The frequent interaction and storage of big data in multi-source networks have broken traditional data silos, enabling cross regional and cross organizational data access, posing significant challenges to data security and privacy protection.As one of the technologies to protect data and resource security, access authentication faces enormous communication loads while obtaining trust from all data nodes, which can cause data loss and damage.Therefore, a blockchain based research method for multi-source network big data security access permission authentication was proposed.The transformation status of data in network transmission using similarity relationships was measured, and the probability of multi-source network data access based on the similarity matrix was calculated.The data security access contracts were established through blockchain technology, calibrating data access attributes and transaction ciphertexts, and compressing data within corresponding attributes.The access reliability based on the purpose of the access was analyzed, reliability was used as the standard to correspond to the security level, rules under different levels of reliability were accessed, specific permissions were authenticated for data security access, and implementation methods were designed.The experimental results show that using different data attribute contents as testing conditions, encrypting and decrypting data in both conventional and attack modes, the new method can achieve fast authentication response and secure access to network data.

    Topic: Energy Internet
    Strategies and system architecture for the ICT-Energy convergence
    Peng GAO, Ziyu XIAO, Sheng ZHANG
    2024, 40(2):  116-123.  doi:10.11959/j.issn.1000-0801.2024031
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    The global demand for green and low-carbon development was analyzed, highlighting that despite sustained increases in global carbon emissions, current efforts fall short of achieving the temperature targets set forth by the Paris Agreement.Green and low-carbon development has thus emerged as a universal consensus and a prevailing trend worldwide.China’s current energy situation and relevant policies were further described, asserting that the ICT-Energy convergence is an inevitable path for future societal digitalization and low-carbonization.Then, the objectives and system architecture of ICT-Energy convergence were proposed.Central to the role of ICT Systems, the architecture embodies three core functionalities, realizing efficient management across all segments of the energy sector through intelligent control, fostering cross-domain synergy between ICT and energy networks and empowering various industries.An exploration of the system synergy mechanisms was conducted within the ICT-Energy converged architecture, and implementation pathways and strategic recommendations for ICT-Energy convergence were outlined.

    Cloud edge end network resource allocation for thermostatically controlled load aggregation regulation
    Yi LIU, Xin WU
    2024, 40(2):  124-140.  doi:10.11959/j.issn.1000-0801.2024029
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    Thermostatically controlled load is a flexible load that controls temperature regulation, such as air conditioning and electric water heaters.As a crucial demand side resource, flexible aggregation and regulation of load clusters can fully mobilize clean energy consumption capacity and ensure the balance between supply and demand of the power grid.Due to the common occurrence of thermostatically controlled loads in commercial office buildings and residential areas, a relatively stable control and transmission method can be adopted.Therefore, an efficient hierarchical transmission network is introduced to achieve data transmission and information interaction between loads and the power grid, and to flexibly, real-time, and accurately utilize the adjustable potential of load clusters.Firstly, an information interaction architecture of load IoT which structured “central cloud-edge cloud-regional load controller-thermostatically controlled load”was proposed.Then, for the “end edge”part, considering the requirements of different aggregation control tasks, an improved clustering algorithm was used to classify the tasks and reduce transmission overhead.For the “end-side” part, an improved clustering algorithm was used to optimize the transmission distance.For the edge-cloud collaboration part, a subchannel resource allocation algorithm was designed based on stable matching and water injection algorithms.The binary particle swarm optimization algorithm was used to solve the task upload decision problem.Finally, the effectiveness of the proposed model and algorithm is verified through simulation, and comparative experiments are also conducted.

    Risk control method for power data support based on embedded technology
    Chengyue YANG, Zhou YU, Yuanyuan ZHAO, Changlong CHEN
    2024, 40(2):  141-149.  doi:10.11959/j.issn.1000-0801.2024030
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    In order to improve the ability of bad data identification and fault location accuracy in power system risk control, a new risk control method for power systems using embedded technology was designed.S3C2440 chip was used as the central processing unit, the phasor measurement unit (PMU) technology was used to identify bad data in the power system, improving the efficiency of identification.Improved on the basis of traditional multiverse algorithms, fault localization was based on data collected by PMU, effectively improving the accuracy of fault localization.In the simulation experiment, the efficiency of identifying bad data by the proposed method has been improved by at least 33.76%, the accuracy of fault localization has been improved by 26.33%, and the efficiency has been improved by at least 43.4%.The proposed method has good risk control capabilities in the power system.

    Research on optimization of air flow organization in substation room air conditioning based on CFD
    Can CHEN, Yang LIU, Li LI, Ping JIA, Xiaofang GAO, Shulin ZHANG
    2024, 40(2):  150-157.  doi:10.11959/j.issn.1000-0801.2024028
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    Due to the continuous improvement of the computer network communication level and the acceleration of data transmission speed, the hardware configuration of the digital signal processing room on the second floor of this unit has become more intensive, and the power consumption and heat generation have also increased.Although the constant temperature and humidity precision air conditioning system has sufficient theoretical cooling capacity, it uses the conventional diffusion air supply mode of cooling the surroundings first and then cooling the device.In a computer system, there are many local over temperature faults due to the uneven distribution of computer load in many areas, which is very difficult to deal with.The existing air distribution cycle has been unable to meet the cooling requirements of equipment with high energy consumption.The examples of the application of optimization and transformation of airflow organization based on CFD in State Grid’s substation computer room was introduced, it has a certain reference significance for energy saving and consumption reduction in computer rooms design.

    Public service resource allocation evaluation and site selection optimization decision making method using PCA-SOM based on autoencoder
    Jun WEI, Hua WANG, Fanglin GUO, Wenbo ZHANG, Rong YANG
    2024, 40(2):  158-168.  doi:10.11959/j.issn.1000-0801.2024034
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    The distribution of urban planning and allocation of public service resources currently lacks consistency and suffers from inefficient siting.Electricity consumption data for public service resources was combined with resource quantity and regional population size to evaluate the allocation of public service resources in each region using principal component analysis (PCA).Additionally, the self-organizing mapping (SOM) algorithm was utilized to optimize the siting of educational resources in Lanzhou City as a case.The power data demonstrated the inadequacy of resource allocation and offered accurate guidance for optimal allocation, especially in Lanzhou City.By utilizing the SOM algorithm, the efficiency of educational resource siting was enhanced, and resource allocation was fairly promoted.This study offers a well-researched justification for public service resource allocation in Gansu Province, and serves as a significant reference point for similar research in other regions.

Copyright Information
Authorized by: China Association for Science and Technology
Sponsored by: China Institute of Communications
Posts and Telecom Press Co., Ltd.
Publisher: Beijing Xintong Media Co., Ltd.
Editor-in-Chief: Chen Shanzhi
Editorial Director: Li Caishan
Address: F2, Beiyang Chenguang Building, Shunbatiao No.1 Courtyard, Fengtai District, Beijing, China
Postal Code: 100079
Tel: 010-53879277
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E-mail: dxkx@ptpress.com.cn
Mailing Code: 2-397
ISSN 1000-0801
CN 11-2103/TN
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