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    20 July 2019, Volume 35 Issue 7
    Analysis and suggestion on 5G networking technology route
    Zhiqin WANG,Fei XU
    2019, 35(7):  3-7.  doi:10.11959/j.issn.1000-0801.2019180
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    In June 2019, the Ministry of Industry and Information Technology officially issued a 5G commercial license, which accelerated the deployment of China’s 5G network. The 5G international standards developed by the 3GPP include non-standalone (NSA) and standalone (SA) modes. In view of the differences between the two, the basic concepts of NSA and SA were introduced. The main characteristics of the two networking modes were compared with performance, work difficulties and key points. The two routes from NSA to SA network evolution and two issues that need attention were analyzed, and the rapid growth of China’s 5G industry was pointed out. In particular, the operating companies had implemented recommendations for implementing development strategies and selecting appropriate networking architectures.

    5G-based networking in unlicensed spectrum
    Min XU, Nan HU, Nan LI
    2019, 35(7):  7-16.  doi:10.11959/j.issn.1000-0801.2019178
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    Due to the growing demand for mobile communication services, the shortage of licensed frequency bands is becoming more and more obvious. Therefore 5G networks begin to consider deployment in the unlicensed spectrum, that is, to employ the NR protocol in unlicensed spectrum to provide access services. The main challenge of 5G networking in the unlicensed spectrum is to support LBT mechanism considering 5G new technical features and thus to guarantee fairness with existing systems as well as efficient spectrum sharing, the impact of LBT on 5G networking in the unlicensed spectrum was analyzed, the relevant standardization progress and challenges was summarized. Feasible and innovative solutions were proposed for some key technical issues to minimize the impact of LBT failure and thus to ensure the performance of 5G networking in the unlicensed spectrum.

    5G new radio design:why/how to extend/innovate from LTE
    Hui TONG
    2019, 35(7):  17-26.  doi:10.11959/j.issn.1000-0801.2019184
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    Driven by the 5G visions including “wireless infrastructure to connect the world”, ITU has defined the three main usage scenarios of 5G: eMBB, mMTC, and uRLLC, and the consequent requirements (performance metrics) are defined as well. Then, 3GPP completed technical studies and standards towards satisfying ITU requirements, namely 5G new radio (NR). Two essential aspects of 5G NR were discussed. Firstly, why can 5G NR reuse the basic technology of 4G LTE was discussed, i. e. , how does the MIMO-OFDM framework satisfy ITU 5G requirements. Secondly, what innovations had been done in 5G NR, comparing with LTE, including some details on the four new features of 5G NR, namely “new architecture, new design, new bands, new antenna”. The future technology trends were briefly introduced in the conclusion section.

    Key technologies of non-orthogonal multiple access for 5G systems
    Yuanyuan DONG, Yujie ZHANG, Hua Li, Chunlei WANG, Xiaofei LIU, Xiaoming DAI
    2019, 35(7):  27-36.  doi:10.11959/j.issn.1000-0801.2019188
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    With the unprecedented increase of mobile data traffic brought by the wide proliferation of smart phones and tablet computers, the non-orthogonal multiple access (NOMA) has attained great attention due to its overloading capability in the case of limited spectrum resources. Firstly, the complexity-constrained NOMA design principle was proposed. Then, a comprehensive study of key NOMA schemes was conducted, in which the theory of each scheme was provided. Next, the low complexity expectation propagation (EP) based detectors were designed. Finally, the performance of NOMA and the conventional orthogonal multiple access (OMA) was compared via simulations. The simulation results illustrate that the NOMA has superior capacity and block error rate (BLER) than the conventional OMA.

    Data-only contention-based grant-free multiple access for 5G mMTC
    Shizhuang ZHANG,Zhifeng YUAN,Weimin LI
    2019, 35(7):  37-46.  doi:10.11959/j.issn.1000-0801.2019177
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    For contention-based grant-free access, reference signal collision would restrict the performance. A data-only contention-based grant-free scheme was considered, where the blind detection receiver does not depend on reference signal to detect users’ information by fully exploiting the characteristics of the data itself, so the limitation from reference signal collision can be avoided, leading to a much higher traffic load. On the other hand, traffic load was further limited by inter-cell interference. Data-only signal does not include cell-specific processing, each cell station could detect all the received signals, including those from adjacent cells, through advanced blind detection receiver. This actually played the role of traditional inter-cell interference cancellation and therefore can achieve a better performance gain. And it would not introduce too much additional complexity.

    Special antenna beamforming method for 5G mobile communication system
    Jianjun HUANG,Xiaoming HUANG
    2019, 35(7):  47-51.  doi:10.11959/j.issn.1000-0801.2019186
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    A method was researched to ensure the uniformity of RX signals in long-distance coverage for 5G applications. In this situation, the antenna pattern model was critical. Firstly, the cosecant-squared shaped beam pattern meets the requirement of uniform coverage through the derivation. Secondly, by constrained optimization algorithm, antenna directivity was taken as objective function, the beam level of specified range was taken as constraint function, to solve the weight parameter of the linear array elements, and the cosecant square pattern could be obtained. MATLAB program completed to realize the algorithm. The innovation was based on constrained optimization algorithm, the real elements patterns were imported, even elevation angle element was proposed in this solution to solve the top blind problem. Finally, the signal level coverage area was compared with which do not have beamforming, it has been shown that cosecant-squared beamforming model can improve the signal uniformity obviously.

    Ultra-wideband array antenna in 5G and its miniaturization technology
    Shenke ZHANG,Fengxu YANG,Yingzeng YIN
    2019, 35(7):  52-59.  doi:10.11959/j.issn.1000-0801.2019185
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    The design method of wideband array antennas and the technology of low profile were studied. Combinations of commercial simulation software ADS and Ansoft HFSS, two design examples of tightly coupled array antennas were presented, with the characteristic of wideband and low profiles. Simulated results show that the impedance bandwidth of voltage stranded ratio less than 2. 0 was from the frequency range of 0.67 GHz to 3. 78 GHz, with a height of 40.25 mm. Moreover, by loaded artificial magnetic conductor (AMC) structure on the basis of the original antenna array to form a high impedance surface to improve the high-frequency resonance performance, the low profile technology was presented for wideband array. The results of full wave electromagnetic simulation software show that the impedance bandwidth of voltage stranded ratio less than 2. 0 was from the frequency range of 1. 1 GHz to 2. 8 GHz, with a height of 24 mm and corresponding to a fractional bandwidth of 78. 0%. This technology can be extended to the development of 5G antennas.

    Secure relay node selection method based on Q-learning for fog computing in 5G network
    Shanshan TU,Jinliang YU,Yuan MENG,M WWAQAS,Lei LIU
    2019, 35(7):  60-68.  doi:10.11959/j.issn.1000-0801.2019176
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    A Q-learning-based optimal dual-relay node selection method was proposed. Firstly, a security fog computing structure model based on social awareness was constructed, and then an optimal dual-relay node selection method based on Q-learning algorithm was designed under this model, which achieved the selection of optimal dual-relay nodes in dynamic environment. Finally, the key generation rate, the selection speed of dual-relay nodes and the selection accuracy of dual-relay nodes in dynamic environment were analyzed. The experimental results show that the scheme can effectively select the optimal dual-relay nodes in dynamic environment, the algorithm converges rapidly to a stable level, and the selection speed of the optimal relay node is effectively improved.

    5G digital wireless indoor coverage solution based on open platform small cell
    Shaohu FANG,Xin LI,Binlong BU
    2019, 35(7):  69-77.  doi:10.11959/j.issn.1000-0801.2019187
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    The challenges and trends of indoor coverage in the 5G era were analyzed, and a 5G digital wireless indoor coverage solution based on open platform small cell was proposed with pointing out its core design element. Based on the impact that 5G technology may have on various industries, the technology enabling of 5G open platform small cell was discussed for several typical industry applications.

    research and development
    A dynamic timeslot-based multicast bandwidth advance reservation algorithm for enterprise video conferencing systems
    Zhiwen LIAO,Ling ZHANG
    2019, 35(7):  78-86.  doi:10.11959/j.issn.1000-0801.2019148
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    In order to guarantee the service quality of video conferencing and improve the utilization of enterprise network resources, the problem of bandwidth advance reservation for enterprise video conferencing system was studied. In an enterprise network, there could be hundreds of conferences held at the same time, and video communication was possible between any two participants. Reserving bandwidth resources in advance for a conference would result in fine-grained changes in available bandwidth over time. In particular, when a large number of conference requests occur at the same time, time consumption and bandwidth usage would increase significantly. To address this problem, a dynamic timeslot-based multicast bandwidth advance reservation algorithm was proposed. The algorithm also took into account the two conference scenarios proposed by the IETF XCON working group. The simulation results show that compared with other algorithms, the algorithm can effectively reserve bandwidth for big data conferences and solve the problem of time overhead bottleneck.

    Data-intensive service deployment based on edge computing
    Yongmei GAO,Guanjie CHENG
    2019, 35(7):  87-99.  doi:10.11959/j.issn.1000-0801.2019170
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    The demand is getting higher and higher for data processing due to big data volume, thus, data-intensive service shave emerged. When solving complex problems, multiple data-intensive services are often united as a service portfolio. Due to the huge data transmission between service components, a great transmission delay will affect the overall performance of the system. In the edge computing environment, an optimized deployment strategy based on the negative selection algorithm was proposed to reduce the data transmission time in the service composition. Firstly, the definition of such a data-intensive service component deployment problem was given, and the deployment problem was modeled as an optimization model; then, a negative selection algorithm was designed to obtain the best deployment solution. In order to evaluate the applicability and convergence of the algorithm, it was compared with genetic algorithm and simulated annealing algorithm. The results show that proposed algorithm outperforms other schemes in this data-intensive service deployment problem.

    Speech emotion recognition algorithm based on spectrogram feature extraction of deep space attention feature
    Jinhua WANG,Na YING,Chendu ZHU,Zhaosen LIU,Zhedong CAI
    2019, 35(7):  100-108.  doi:10.11959/j.issn.1000-0801.2019052
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    Starts from the extraction and classification modeling of speech emotion features, based on the hybrid convolutional neural network model, the Itti model in feature extraction was improved, including increasing the extraction by local binary mode. The strong correlation features were extracted combining with the sensitivity of the auditory sensitivity. Then, the constrained extrusion and excitation network structure of the calibration weights were extracted by feature constraints. Finally, a fine-tuning model based on VGGnet and long-short-time memory network hybrid network was formed, further enhancing the ability to express emotions. By validating on the natural sentiment database and the German-German database, the model had a significant increase in the rate of sentiment recognition, which is 8. 43% higher than the benchmark model. At the same time, the recognition effect of the model on the natural database (FAU-AEC) and the Berlin database (EMO-DB) were compared. The experimental results show that the model has a good generalization.

    Feasibility analysis on frequency utilization of discrete carrier aggregation broadband systems in the 223~235 MHz band
    Peichuan KANG,Huiling DAI,Yu PAN,Jian FANG
    2019, 35(7):  109-114.  doi:10.11959/j.issn.1000-0801.2019169
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    Discrete carrier aggregation broadband systems were introduced in the 223~235 MHz band to improve spectrum utilization efficiency and to meet the broadband application demand of industrial users. The interference between broadband system and in-band narrow band wireless radio were analyzed considering both single station interference and aggregated effect. Also, the interference between broadband system and out-of-band TV broadcasting system were calculated. Finally, the feasibility of frequency usage was proposed based on the interference calculation results.

    An audio steganography algorithm based on segment-STC
    Xueyuan ZHANG,Rangding WANG,Diqun YAN,Yuzhen LIN
    2019, 35(7):  115-123.  doi:10.11959/j.issn.1000-0801.2019071
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    In steganography field, syndrome-trellis code is a state-of-the-art steganography algorithm. A steganography algorithm of Segment-STC was proposed. Segment-STC could locally optimize the distortion by segmentation. Firstly, the LSB-stream (least significant bit, LSB) of audio cover was segmented as few sub-segments. Then, the segmented message in each sub-segment was embedded to the optimal submatrix. The TIMIT dataset and author collected online songs as databases was used to run the experiments. Results show that segment-STC can effectively reduce the number of distortion elements of cover and improve the undetectability of the stego. Segment-STC algorithm can reduce the distortion over 24%, compared with the original STC algorithm. It also has a better imperceptible performance compare with other similar audio steganography algorithms.

    Research progress of the antenna technology for internet of things
    Wenjun LV,Jian YU,Hongbo ZHU
    2019, 35(7):  124-135.  doi:10.11959/j.issn.1000-0801.2019171
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    From the perspectives of RFID antennas, wearable/implantable antennas, multi-physical sensing antennas, energy harvesting antennas, and on-chip package antennas based on advanced materials and processes, the current research progress of antenna technology for internet of things was introduced. Combined with the research and teaching practice in the field of antennas in recent years, the multi-harmonic antenna design theory based on the “single-cavity multi-mode” idea and the application of the internet of things were proposed. Finally, several application examples based on this theory were listed.

    Operation technology wide Angle
    Application of machine learning in the fake user identification of IoT
    Rongfang ZHANG,Dandan XU,Yuanguang WANG,Siyu PAN,Zhengmao LI
    2019, 35(7):  136-144.  doi:10.11959/j.issn.1000-0801.2019090
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    With the development of communication technology, IoT cards and 5G technologies will be applied on a large scale. However, there are some companies have taken advantage of the fact that the price of SIM cards of IoT is cheap and the cards do not have real-name registration system. It is harmful to social stability, which is not conducive to the development of IoT industry. So how to identify these fake users has become an important topic in IoT industry. The purpose was to use machine learning models to identify users who have high suspiciousness effectively. By studying the characteristics of relevant data, a semi-supervised learning model based on positive and unlabeled samples was used to establish a real-time abnormal behavior monitoring model to identify potential fake users in the IoT industry users. At the same time, the model greatly enhanced the working efficiency and has saved the manpower physical resources. Also, it can help relevant departments and governments to discover the abnormal behavior of users in time and take corresponding measures to avoid large losses. So, the proposed method really has broad application prospects in the industry.

    Scheme analysis of transmission network for 5G mobile communication system
    Lili WANG,Jun YAO
    2019, 35(7):  145-151.  doi:10.11959/j.issn.1000-0801.2019174
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    The service requirements of the three typical scenarios in the 5G era put forward higher requirements on the capacity, delay and networking flexibility of the bearer network. At the same time, the changes of the wireless network and the core network architecture propose the requirements of network slicing and enhanced routing and forwarding functions. Firstly, the 5G bearer requirements were analyzed, and the 3G typical service scenarios of 5G and the architecture changes of the wireless and core networks were considered. Then, based on the actual application of the 100GE PTN, the benchmarking of the demand and the status quo of the network was completed mainly around dimensions such as capacity, latency, etc. Finally, the evolution plan of network backhaul and computer room supporting was proposed.

    Evolutionary logic and operational mechanism of E-commerce platform
    Zelin LU,Qiangzhi LI
    2019, 35(7):  152-158.  doi:10.11959/j.issn.1000-0801.2019173
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    The E-commerce platform in the era of digital economy has evolved into a data platform ecosystem built around data resources and data technology systems, which greatly reduces transaction costs, improves production efficiency, and optimizes economic structure. Firstly, the macro environment of E-commerce development and the concept of E-commerce platform were introduced, and then the evolution of China E-commerce platform and the operation mechanism of E-commerce platform were analyzed.

    Automated anomaly detection of IPTV user experience
    Xiaomin TAN,Ai FANG,Duo JIN,Changjiang LI
    2019, 35(7):  159-164.  doi:10.11959/j.issn.1000-0801.2019051
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    Architecture of IPTV system is complex, involving a large number of terminals, network elements and connections. Therefore, a relatively complete monitoring system, which collected massive EPG experience data and formed multi-dimensional monitoring indicators, had been established to monitor user experience. Due to a large number of indicators, manual monitoring was time consuming and laborious. It was hard to detect anomalies in time and it was impossible to determine the cause of abnormality. To solve the pain points of the operation, an intelligent algorithm was implied and improved to analyze massive experience data. The practice indicates that the algorithm with low calculation cost adapts to abnormal changes in the network and detect anomalies accurately and quickly, which reduces labor costs, improves operation efficiency and promotes intelligent operation.

    Research on terminal switch interval based on DTL
    Yufei CUI,Jinwu WEI,Siyu PAN,Rongfang ZHANG,Xiao WANG,Zixiang JIA
    2019, 35(7):  165-172.  doi:10.11959/j.issn.1000-0801.2019098
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    With the rapid development of mobile internet, the population dividend of operators is gradually saturated, and the switch node of user mobile terminal has become the focus of operators’ attention. The switching frequency of users was predicted by decision tree algorithm based on the consumption information of user history and the replacement information of mobile terminals, which provided data support for the accurate marketing of mobile terminals and the stock management of users.

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ISSN 1000-0801
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