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Analysis of connectivity in Ad-hoc network based on interference and fading channel

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The Journal of China Universities of Posts and Telecommunications 2012年第5期19卷 77-82页

作者： XU Bin-tai ZHU Qi HU Han Jiangsu Key lab of Wireless communications Key Lab on Wideband Wireless Communications and Sensor Network Technology of Ministry of Education

In Ad-hoc wireless network, connectivity is a fundamental issue which restricts the design of system protocol. Based on the theory of stochastic geometry, a connectivity model focused on signal-to-interference （SIR） ratio is set up in presence of Nakagami-m fading and interference. This paper derives a close formula of connectivity probability with interference and Nakagami-m fading which is never obtained in previous works. Two-dimension shot-noise theory in stochastic geometry for interference is well applied. The formula is verified by simulation. The results show that the connectivity is affected by the scatter of users, wireless propagation environment, interference and so on.

关键词： Ad-hoc wireless network connectivity the probability of isolated node interference Nakagami-m fading

Joint Resource Allocation Using Evolutionary Algorithms in Heterogeneous Mobile Cloud Computing Networks

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China communications 2018年第8期15卷 189-204页

作者： Weiwei Xia Lianfeng Shen National Mobile communications Research lab Southeast University

The problem of joint radio and cloud resources allocation is studied for heterogeneous mobile cloud computing networks. The objective of the proposed joint resource allocation schemes is to maximize the total utility of users as well as satisfy the required quality of service(QoS) such as the end-to-end response latency experienced by each user. We formulate the problem of joint resource allocation as a combinatorial optimization problem. Three evolutionary approaches are considered to solve the problem: genetic algorithm(GA), ant colony optimization with genetic algorithm(ACO-GA), and quantum genetic algorithm(QGA). To decrease the time complexity, we propose a mapping process between the resource allocation matrix and the chromosome of GA, ACO-GA, and QGA, search the available radio and cloud resource pairs based on the resource availability matrixes for ACOGA, and encode the difference value between the allocated resources and the minimum resource requirement for QGA. Extensive simulation results show that our proposed methods greatly outperform the existing algorithms in terms of running time, the accuracy of final results, the total utility, resource utilization and the end-to-end response latency guaranteeing.

关键词： heterogeneous mobile cloud computing networks resource allocation genetic algorithm ant colony optimization quantum genetic algorithm

Uplink Performance Analysis in Multi-Tier Heterogeneous Cellular Networks with Power Control and Biased User Association

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China communications 2016年第12期13卷 25-36页

作者： Han Hu Hong Wang Qi Zhu Ziyu Pan Jiangsu Key lab of Wireless communications Key Lab on Wideband Wireless Communications and Sensor Network Technology of Ministry of EducationNanjing University of Posts and Telecommunications

A K-tier uplink heterogeneous cellular network is modelled and analysed by accounting for both truncated channel inversion power control and biased user association. Each user has a maximum transmit power constraint and transmits data when it has sufficient transmit power to perform channel inversion. With biased user association, each user is associated with a base station(BS) that provides the maximum received power weighted by a bias factor, but not their nearest BS. Stochastic geometry is used to evaluate the performances of the proposed system model in terms of the outage probability and ergodic rate for each tier as functions of the biased and power control parameters. Simulations validate our analytical derivations. Numerical results show that there exists a trade-off introduced by the power cut-off threshold and the maximum user transmit power constraint. When the maximum user transmit power becomes a binding constraint, the overall performance is independent of BS densities. In addition, we have shown that it is beneficial for the outage and rate performances by optimizing different network parameters such as the power cut-off threshold as well as the biased factors.

关键词： Heterogeneous cellular network uplink performance biased user association stochastic geometry

Power distribution algorithm based on game theory in the femtocell system

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The Journal of China Universities of Posts and Telecommunications 2013年第2期20卷 42-47页

作者： MU Shi-yao ZHU Qi Jiangsu Key lab of Wireless communications Key Lab on Wideband Wireless Communications and Sensor Network Technology of Ministry of Educations Nanjing University of Posts and Telecommunications

This paper studies the power control problem in femtocell system based on Nash non-cooperative game theory. It designs an utility function taking fem stations＇ transmit power as variable and relates it to the requirements of macro users＇ and fem users＇ signal to interference plus noise ratio （SINR）. The utility also takes the impact of fem stations＇ location into account and improves the fairness of non-cooperative game. On this basis, this paper proposes a distributed power control algorithm and proves the existence and uniqueness of Pareto optimal point. The simulation results show that the algorithm improves the convergence speed and system performance through improving users＇ SINR.

关键词： Nash non-cooperative game power control utility function

Power frequency AC voltage measurement based on double wound Rogowski coil

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High Voltage 2017年第2期2卷 129-135页

作者： Mohamed E.Ibrahim Amr M.Abd-Elhady High Voltage and Dielectric Materials lab. Faculty of EngineeringMenoufia UniversityShebin El_Kom 32511Egypt

This study presents a technique for power frequency AC voltage *** proposed technique utilises a capacitor having a low capacitance in addition to a double wound Rogowski *** technique depends on capacitor current measurement using the double wound Rogowski *** voltage across the capacitor that connected in parallel with the system at which AC voltage is intended to be measured is *** proposed technique is experimentally evaluated by designing the measurement system and using a digital signal processing board for the reconstruction ***,the experimental results based on Rogowski coil measurements are compared with those obtained from reference ***,the obtained results validate the efficacy of the proposed technique in power frequency AC voltage measurement.

关键词： Rogowski double capacitance

Network selection algorithm based on AHP and similarity

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The Journal of China Universities of Posts and Telecommunications 2018年第2期25卷 77-88,104页

作者： Li Wanghong Zhu Qi Jiangsu Key lab of Wireless communications Nanjing University of Posts and Telecommunications

In heterogeneous wireless networks, there are various kinds of service demands from the users. A network selection algorithm based onthe analytic hierarchy process （AHP） and Similarity is proposed to solve this problem. The services are divided into three classes： Conversational Class, Streaming Class and Interactive Class. According to the characteristics of each service, a different judgment matrix is assigned and then the AHP method is used to calculate the network attribute weights. Taking the dynamic changes in user demands and network environment into account, a formula based on Lance distance for computing the attributes similarity is derived to evaluate the degree of conformity between user requirements and network attributes, from which the similarity between the user requirements and network attributes is calculated and then the total similarity by weighting. The network with the largest total similarity is the best choice. Simulation results demonstrate the effectiveness of the proposed scheme in improving the quality of service （QoS） according to the user requirements under three kinds of services.

关键词： AHP attributes similarity service type network selection

Power-time resource allocation for downlink SWIPT-assisted cooperative NOMA systems

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Science China(Information Sciences) 2023年第5期66卷 238-247页

作者： Chengpeng LIU Lin ZHANG Zhi CHEN Shaoqian LI National Key lab of Science and Technology on communications University of Electronic Science and Technology of China

We study a downlink cooperative non-orthogonal multiple access(NOMA) system in which a base station(BS) serves two paired users on the same frequency band simultaneously, and the near user acts as an energy-constrained relay for the far user since there is no direct link between the BS and the far user due to physical obstacles or heavy shadowing. To replenish energy of the near user for relaying, we enable the near user to harvest energy from BS signals by adopting the simultaneous wireless information and power transfer(SWIPT) technique. Diferent from the linear energy harvesting(EH) model used in most of the existing literature, we adopt a non-linear model for EH. By considering the non-linear features of the practical circuits, we aim to minimize the BS energy consumption while ensuring the minimum required transmission rate of both users. Since the formulated problem contains coupled power and time resource variables, it is challenging to solve it directly. Thus, we propose an optimal power-time resource allocation algorithm by decoupling the variables properly. Simulation results verify the theoretical analysis and show the performance of the considered system.

关键词： NOMA SWIPT relaying non-linear transmit energy

Towards converged, collaborative and co-automatic (3C) optical networks

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Science China(Information Sciences) 2018年第12期61卷 34-52页

作者： Yuefeng JI Jiawei ZHANG Xin WANG Hao YU State Key lab of Information Photonics and Optical communications Beijing University of Posts and Telecommunications (BUPT)

The interconnection of all things is developing a new diagram of future information ***, it is difficult to realize future applications with only one single technique. Collaboration between multiple advanced techniques is leading the way for the development of future information networks. Optical communication is an enabling technique to achieve high speed, long reach, and low latency communication,which plays an important role on the transformation of information networks. To achieve these advantages that caters to the characteristics of future information networks, collaboration of multiple advanced techniques with optical, which is called "optical plus X", could realize the vision of "all things connected with networks". In this paper, we focus on the collaboration between optical networks with other techniques,mainly discuss four representative aspects, which are "optical plus IP", "optical plus radio", "optical plus computing", and "optical plus AI". We discuss the challenges, timely works, and developing trends. Finally,we give the future visions for optical network towards a collaborative, converged and co-automatic optical network.

关键词： 5G optical transport networks edge computing optical networks IP over optical networks AI-assisted optical networks 3C optical networks

5G Flexible Optical Transport Networks with Large-Capacity, Low-Latency and High-Efficiency

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China communications 2019年第5期16卷 19-32页

作者： Yuefeng Ji Jiawei Zhang Yuming Xiao Zhen Liu State Key lab of Information Photonics and Optical communications Beijing University of Posts and Telecommunications

The fifth generation(5G) of mobile communications are facing big challenges, due to the proliferation of diversified terminals and unprecedented services such as internet of things(IoT), high-definition videos, virtual/augmented reality(VR/AR). To accommodate massive connections and astonish mobile traffic, an efficient 5G transport network is required. Optical transport network has been demonstrated to play an important role for carrying 5G radio signals. This paper focuses on the future challenges, recent studies and potential solutions for the 5G flexible optical transport networks with the performances on large-capacity, low-latency and high-efficiency. In addition, we discuss the technology development trends of the 5G transport networks in terms of the optical device, optical transport system, optical switching, and optical networking. Finally, we conclude the paper with the improvement of network intelligence enabled by these technologies to deterministic content delivery over 5G optical transport networks.

关键词： 5G optical transport networks optical devices optical transport system optical switching optical networking