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Optimize the Deployment and Integration for Multicast-Oriented Virtual Network Function Tree

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Journal of Beijing Institute of Technology 2022年第5期31卷 513-523页

作者： Ying Chang Hongxue Yang Qinghua Zhu School of Telecommunication Engineering Beijing PolytechnicBeijing 100176China

Due to the development of network technology,the number of users is increasing rapidly,and the demand for emerging multicast services is becoming more and more abundant,traffic data is increasing day by day,network nodes are becoming denser,network topology is becoming more complex,and operators’equipment operation and maintenance costs are increasing.Network functions virtualization multicast issues include building a traffic forwarding topology,deploying the required functions,and directing traffic.Combining the two is still a problem to be studied in depth at present,and this paper proposes a two-stage solution where the decisions of these two stages are interdependent.Specifically,this paper decouples multicast traffic forwarding and function delivery.The minimum spanning tree of traffic forwarding is constructed by Steiner tree,and the traffic forwarding is realized by Viterbi-algorithm.Use a general topology network to examine network cost and service performance.Simulation results show that this method can reduce overhead and delay and optimize user experience.

关键词： multicast service function chain(SFC) network functions virtualization(NFV) software defined network(SDN) Viterbi-algorithm

Switched-Beam Optimization for an Indoor Visible Light Communication Using Genetic Algorithm

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Computers, Materials & Continua 2022年第4期71卷 1547-1566页

作者： Ladathunya Pumkaew Monthippa Uthansakul Peerapong Uthansakul School of Telecommunication Engineering Institute of EngineeringSuranaree University of TechnologyNakhon Ratchasima30000Thailand

Nowadays, Visible Light Communication (VLC) is an attractivealternative technology for wireless communication because it can use somesimple Light Emitting Diodes (LEDs) instead of antennas. Typically, indoorVLC is designed to transmit only one dataset through multiple LED beams at atime. As a result, the number of users per unit of time (throughput) is relativelylow. Therefore, this paper proposes the design of an indoor VLC system usingswitched-beam technique through computer simulation. The LED lamps aredesigned to be arranged in a circular array and the signal can be transmittedthrough the beam of each LED lamp with the method of separating the datasetto increase the number of simultaneous users for enhancing the indoor VLC.The coverage area is determined from the area where the communication canbe performed at a location on the receiving plane with a Bit Error Rate lessthan or equal to the specified value based on coverage illuminance accordingto International Commission on Illumination (CIE) standards. In this paper,Genetic Algorithm is used to find the suitable solution for designing parameters to achieve maximum coverage area. The results show that a GeneticAlgorithm can be used to find a suitable solution and reduce the computationaltime approximately 382 min in proposed scenarios.

关键词： Visible light communication genetic algorithm optimization light emitting diode

Scalable Security Solution Against Wiretapping for Network Coding Based Priority Encoding Transmission

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Chinese Journal of Electronics 2018年第1期27卷 191-197页

作者： LIU Guangjun XIAO Song school of Information engineering Xi'an University School of Telecommunication Engineering Xidian University

Network coding is promising to improve the throughput and robustness of video transmission over wireless networks. To address the security issue of network coding based Priority encoding transmission(PET), a special coding design against wiretapping is proposed with hierarchical security. The basic idea is first to randomize partial blocks of each layer and then to encode each layer with inter-layer overlapping coding. The method is characterized by quantifiable security for incremental decoding,and realizes scalability in confidentiality and video transmission, while incurring relatively low computational complexity and bandwidth overhead. A sufficient condition is also presented to design a stronger secure network coded PET system against the known-plaintext attacks. Analysis and evaluation show that the method can be efficient as a new paradigm to secure network coded PET system in realistic applications.

关键词： Network coding Hierarchical confidentiality Priority encoding transmission(PET) Video streaming

Optimal Hybrid Precoding Based QoE for Partially Structured Massive MIMO System

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Computers, Materials & Continua 2022年第4期71卷 1887-1902页

作者： Farung Samklang Peerapong Uthansakul Monthippa Uthansakul Patikorn Anchuen School of Telecommunication Engineering Suranaree University of TechnologyNakhon Ratchasima30000Thailand

Precoding is a beamforming technique that supports multi-streamtransmission in which the RF chain plays a significant role as a digital precoding at the receiver for wireless communication. The traditional precodingcontains only digital signal processing and each antenna connects to each RFchain, which provides high transmission efficiency but high cost and hardwarecomplexity. Hybrid precoding is one of the most popular massive multipleinput multiple output (MIMO) techniques that can save costs and avoid usingcomplex hardware. At present, network services are currently in focus with awide range of traffic volumes. In terms of the Quality of Service (QoS), it iscritical that service providers pay a lot of attention to this parameter and itsrelationship to Quality of Experience (QoE) which is the measurement of theoverall level of user satisfaction. Therefore, this paper proposes hybrid precoding of a partially structured system to improve transmission efficiency andallocate resources to provide network services to users for increasing the usersatisfaction under power constraints that optimize the quality of basebandprecoding and radio frequency (RF) precoding by minimizing alternatingalgorithms. We focus on the web browsing, video, and Voice over IP (VOIP)services. Also, a Mean Opinion Score (MOS) is employed to measure thelevel of user satisfaction. The results show that the partially structured systemprovides a good user satisfaction with the network’s services. The partiallystructured system provides high energy efficiency up to 85%. Considering webservice, the partially structured system for 10 users provides MOS at 3.21 whichis higher than 1.75 of fully structured system.

关键词： Massive MIMO quality of experience(QoE) mean opinion score(MOS) quality of service(QoS) hybrid precoding partially structured system

Preparation and photocatalytic properties of porous C and N co-doped TiO_2 deposited on brick by a fast, one-step microwave irradiation method

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Journal of Environmental Sciences 2017年第10期29卷 24-32页

作者： Fangzhou Li Jiangshan Zhou Chun Du Wei Li Yinzhen Wang Guannan He Qinyu He South China Normal University School of Physics & Telecommunication Engineering

A one-step microwave irradiation method was used to deposit carbon and nitrogen co-doped TiO2（（C, N）-TiO2） on commercial brick（（C, N）-TiO2/brick）. The as-prepared samples were characterized by X-ray diffraction, ultraviolet–visible（UV–vis） diffuse reflectance spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy（SEM）. A selective technique was also used to investigate the concentration of hydroxyl radicals during UV–vis irradiation of the Methyl Orange solution with the as-prepared samples. The C and N dopants enhanced visible light absorption and provided a longer lifetime for the photo-generated electron–hole pairs. The SEM images showed that the as-prepared sample is porous. The dark adsorption and photodegradation test for（C, N）-TiO2/brick showed good photodegradation and good recyclability. The best photodegradation rate was 94% after 2 hr. The maximum degradation rate was maintained even after the 6th cycle. The good photocatalytic properties are attributed to the enhanced visible light absorption, enhanced pollutant adsorption arising from the porous structure of the（C, N）-TiO2 thin film, and longer lifetime of the photo-generated electron–hole pairs.（C, N）-TiO2/brick should have potential commercial applications in photodegradation processes because of its low cost, good photodegradation, and excellent recyclability.

关键词：（C,N）-TiO2/brick hybridization Low cost Longer lifetime Good photocatalytic properties Good recyclability

Achievement of Bluetooth adaptive packet selection strategies based on SNR estimation

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The Journal of China Universities of Posts and telecommunications 2016年第1期23卷 8-13,48页

作者： Li Jing Chen Wanzhong Zhao Xiaohui School of Telecommunication Engineering Jilin University

It is necessary to estimate channel quality in order to put Bluetooth adaptive packet selection strategies into practice. However, the current Bluetooth channel quality estimation algorithms are either poor at timeliness or not applicable to systems which only support basic rate （BR） data packets （Gaussian frequency shift keying （GFSK） modulation scheme）. It is investigated to apply the channel quality estimation algorithm based on power spectrum to Bluetooth adaptive packet selection strategies in this paper. Simulation results and analysis show that the proposed channel quality estimation algorithm based on power spectrum can achieve the accuracy less than 0.2 dB in the estimation range required by Bluetooth adaptive packet selection strategies. It has simple calculation and strong timeliness. The algorithm can also be suitable for different modulation schemes of Bluetooth data packets. It provides a good precondition for the achievement of Bluetooth adaptive packet selection strategies.

关键词： computer application Bluetooth power spectrum signal-to-noise ratio estimation

Discrimination of maleic hydrazide polymorphs using terahertz spectroscopy and density functional theory

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Optoelectronics Letters 2023年第8期19卷 493-497页

作者： ZHENG Zhuanping ZHAO Shuaiyu LIU Yuhang GONG Jiamin school of Electronic engineering Xi’an University of Posts&TelecommunicationXi’an 710121China

The terahertz(THz) absorptions of maleic hydrazide polymorphs(MH2 and MH3) have been measured utilizing terahertz time-domain spectroscopy(THz-TDS).MH2 and MH3 have displayed totally different THz absorption features compared to their basically identical infrared spectral peaks.Experimental THz spectrum of MH2 showed six distinct absorption features while MH3 demonstrated five characteristic absorption peaks in the range of 10—160 cm^(-1).Spectral interpretation has been carried out in the framework of density functional theory(DFT) using periodic unit cell models.The simulation yields a good quality with respect to the measured features.Further analysis into the mode of vibration showed that the low-frequency THz spectral features(<112 cm^(-1)) are contributed by intermolecular interactions mediated by in-plane/out-of-plane collective vibrations.The varied intermolecular interactions and crystal habits are the primarily reason for the THz spectral differences of MH2 and MH3.

关键词： absorption spectroscopy functional

Robust hybrid beamforming design for millimeter-wave massive MIMO systems

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The Journal of China Universities of Posts and telecommunications 2019年第3期26卷 44-49页

作者： Zhang Kai Xu Guixian Yin Changchuan Liu Danpu School of Telecommunication Engineering Beijing University of Posts and Telecommunications

Hybrid analog-digital beamforming is recognized as a promising solution for a practical implementation of massive multiple-input multiple-output(MIMO) systems based on millimeter-wave(mmWave) technology. In view of the overwhelming hardware cost and excessive power consumption and the imperfection of the channel state information(CSI), a robust hybrid beamforming design is proposed for the mmWave massive MIMO systems, where the robustness is defined with respect to imperfect knowledge or error of the CSI at the transmitter due to limited feedback and/or imperfect channel estimation. Assuming the errors of the CSI are bounded, the optimal hybrid beamforming design with robustness is formulated to a mean squared error(MSE) minimization problem. An iterative semidefinite programming(SDP) based algorithm is proposed to obtain the beamforming matrices. Simulation results show that the proposed robust design can provide more than 4 dB performance gain compared to that of non-robust design.

关键词： hybrid beamforming imperfect CSI massive MIMO millimeter-wave MSE

Fully Connected Feedforward Neural Networks Based CSI Feedback Algorithm

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China Communications 2021年第1期18卷 43-48页

作者： Ming Gao Tanming Liao Yubin Lu School of Telecommunication Engineering Xidian UniversityXi’an 710071China

In modern wireless communication systems,the accurate acquisition of channel state information(CSI)is critical to the performance of beamforming,non-orthogonal multiple access(NOMA),etc.However,with the application of massive MIMO in 5G,the number of antennas increases by hundreds or even thousands times,which leads to excessive feedback overhead and poses a huge challenge to the conventional channel state information feedback scheme.In this paper,by using deep learning technology,we develop a system framework for CSI feedback based on fully connected feedforward neural networks(FCFNN),named CF-FCFNN.Through learning the training set composed of CSI,CF-FCFNN is able to recover the original CSI from the compressed CSI more accurately compared with the existing method based on deep learning without increasing the algorithm complexity.

关键词： massive MIMO CSI feedback deep learning fully connected feedforward neural network