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68th IEEE Vehicular Technology Conference

作者： Ruan, Liang Zhang, Jianhua Zhang, Yanyan Xia, Minghua Beijing Univ Posts & Telecom Minist Educ Key Lab Univ Wireless Commun Beijing 100876 Peoples R China Beijing Univ Posts & Telecommun Wireless Technol Innovat Inst Beijing 100876 Peoples R China Elect & Telecommun Res Inst Daejeon South Korea

ISBN: (纸本)9781424417223;9781424417216

In orthogonal frequency division multiplexing (OFDM) systems, time- and frequency-selective (or doubly-selective) fading leads to the loss of subcarrier orthogonality and the occurrence of inter-carrier interference (ICI), which increases an irreducible error floor in proportional to the normalized Doppler frequency offset. Channel estimation (CE) in rapidly time-varying multi-path scenarios is critical for ICI cancellation and coherent demodulation. In this paper, we introduce an iterative CE scheme to estimate time-varying channel parameters and a low-complexity equalization method to cancel ICI and detect data. The proposed CE technique performs an initial CE based on a piece-wise linear model. Then ICI is reconstructed and cancelled from the received signals. Estimating channel again by using signals of less interference, refined CE can be obtained. Meanwhile, a low-complexity equalizer is proposed to further improve BER performance. Finally, simulation results show good performance of the proposed CE method in doubly-selective fading channels.

关键词： Channel estimation doubly-selective channel equalization inter-carrier interference (ICI) cancellation OFDM time-varying frequency-selective channel

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Influence Analysis of Typical Objects in Rural Railway Environments at 28 GHz

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2019年第3期68卷 2066-2076页

作者： He, Danping Ai, Bo Schmieder, Mathis Zhong, Zhangdui Kim, Junhyeong Hui, Bing Chung, Heesang Kim, Ilgyu Hao, Yang Beijing Jiaotong Univ State Key Lab Rail Traff Control & Safety Beijing 100044 Peoples R China Beijing Engn Res Ctr High Speed Railway Broadband Beijing 100044 Peoples R China Fraunhofer Heinrich Hertz Inst Wireless Commun & Networks Dept D-10587 Berlin Germany Elect & Telecommun Res Inst Mobile Applicat Res Dept Daejeon 34129 South Korea Korea Adv Inst Sci & Technol Sch Elect Engn Daejeon 34141 South Korea Elect & Telecommun Res Inst Future Mobile Commun Res Div Daejeon 34129 South Korea Queen Mary Univ London Sch Elect Engn & Comp Sci London E1 4NS England

Millimeter wave (mmWave) is a key to realize high data-rate communication and enable smart railway services. There are more and more research work focusing on the algorithm and system design for railway communications in the mmWave band. A correct understanding of the mmWave channel characteristics for railway scenario is important for the estimation and evaluation of designed technologies. In this paper, the influence of typical objects in rural railway environment to the mmWave propagation channel is analyzed. Based on the channel measurement conducted at 28 GHz with train-to-infrastructure deployment in the rural railway environment, a ray tracing (RT) simulator is calibrated in terms of environment modeling and electromagnetic (EM) calculation. The dominant multipath components of the measurement are tracked and matched with corresponding objects in the propagation environment. Accordingly, dominant propagation mechanisms (direct, penetration, reflection, scattering, etc.) are determined, the three-dimensional environment model and the EM parameters of different objects are calibrated. To overcome the constraints of the measurement and analyze the influence more practically, the measurement campaign is extended to four different environment cases and four T2I deployments. With the predetermined dominant propagation mechanisms and calibrated EM parameters, reliable RT simulations are conducted. The influence of typical objects are analyzed for the considered environment cases and deployments. The analysis of this paper not only helps to understand the important influential factors of propagation channel at the object level, but also can be useful in guiding deployment of mmWave communication system. The provided EM parameters and environment modeling suggestions will enable reliable RT based channel realization in rural railway environments.

关键词： Channel measurement influence analysis millimeter wave channel railway communication ray-tracing simulation

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Height Gain Modeling of Outdoor-to-Indoor Path Loss in Metropolitan Small Cell Based on Measurements at 3.5 GHz

Height Gain Modeling of Outdoor-to-Indoor Path Loss in Metro...

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International Symposium on Wireless Personal Multimedia Communications (WPMC)

作者： Li, Chong Zhao, Zhuyan Tian, Lei Zhang, Jianhua Zheng, Zhe Kang, Jianfeng Guan, Hao Zheng, Yi Sun, Haihan Beijing Univ Posts & Telecom Minist Educ Key Lab Universal Wireless Commun Beijing Peoples R China Nokia Solut & Networks Beijing Beijing Peoples R China China Mobile Res Inst Beijing Peoples R China Beijing Univ Posts & Telecom Sch Informat & Telecommun Engn Beijing Peoples R China

ISBN: (纸本)9789860334074

In the last few years, the growing demand of wireless data services has brought great pressure on wireless network in dense urban environment. Small cells are widely deployed to increase data capacity. But when the outdoor base station and indoor users in high-rising buildings get close, indoor users begin to suffer dramatic change in path loss due to height difference between the transmitter (TX) and receiver (RX). In this paper, a measurement campaign to research the Outdoor-to-Indoor (O2I) path loss in metropolitan small cell scenario was carried out. The analysis of the measurement data shows that in typical small cell scenario, the O2I path loss has a tendency of increasing with the height difference, which is defined as height gain. Height gain is observed in both the outdoor part and the wall penetration part of the O2I path loss, and it value is also found to relate to the distance between TX and RX. By taking the height difference into consideration when calculating the distance, the path loss of the outdoor part is modified. And by introducing a height gain factor, the height gain of the wall penetration part is modeled based on measurement data. The path loss prediction with height gain model fits in well with the measurement data.

关键词： Cytology

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A novel timing synchronization method for MIMO OFDM systems

A novel timing synchronization method for MIMO OFDM systems

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67th IEEE Vehicular Technology Conference

作者： Feng, Chong Zhang, Jianhua Zhang, Yanyan Xia, Minghua Beijing Univ Posts & Telecom Minist Educ Key Lab Universal Wireless Commun POB 92 Beijing 100876 Peoples R China Beijing Univ Posts & Telecom Wireless Technol Innovat Inst Beijing 100876 Peoples R China Elect & Telecommun Res Inst Daejeon South Korea

ISBN: (纸本)9781424416448

This paper presents a timing synchronization method with shift-orthogonal Constant Amplitude Zero Auto Correlation (CAZAC) sequences for the multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. Utilizing the unique properties of CAZAC sequences, at the receivers, unit pulses can be obtained by the symmetrical correlation to detect time offsets and differentiate inter-transmitter delays (ITDs). The performance of the proposed method is compared with traditional methods at different values of ITDs. Simulations demonstrate that the proposed CAZAC sequence-based method provides high accuracy in detecting the different time offsets caused by the distributed transmitters of the MIMO OFDM systems.

关键词： CAZAC MIMO OFDM timing synchronization

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Approximation error analysis for partially coherent EGC receiver under Nakagami-m fading channels

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IEICE TRANSACTIONS ON COMMUNICATIONS 2007年第5期E90B卷 1245-1248页

作者： Kim, Youngsun Kim, Kiseon KERI Power Telecommun Network Res Lab Uiwang City Gyeonggi Do South Korea Gwangju Inst Sci & Technol Commun & Sensor Networks Lab Kwangju South Korea

We present the approximated bit error rate (BER) performance of a binary phase shift keying (BPSK) modulated equal-gain combining (EGC) diversity receiver with phase noise over independent and non-identical Nakagami fading branches. The approximated BER becomes accurate with phase-locked loop (PLL) gain, K = 20. Also, for special values of fading parameter, m, and branch number, L, we derived the closed form expression of the BER.

关键词： equal-gain combining phase noise Nakagami fading channels

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Performance analysis of an N-level shaper for VBR video traffic in ATM networks

Performance analysis of an N-level shaper for VBR video traf...

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International Conference on Communication Technology (ICCT)

作者： Myeong-Yong Lee Sin-Myeong Mun Jeong-Sik Hong Chang-Hun Lie Telecommun. Networks Res. Labs. Korea Telecom Seoul South Korea Department of Industrial Engineering Seoul National University South Korea

ISBN: (纸本)0780329163

Based on the buffer occupancy level, an N-level shaper regulates the input cell rate of a VBR video source. In this paper the stochastic fluid flow approximation is used to analyze the shaping characteristics on the assumption that the cell arrival process model for a single video source is the superposition of homogeneous on-off minisources. We derive the closed form solutions of the standard deviation-to-average ratio and the shaping delay as measures of the shaping effect. The effectiveness of the proposed shaping mechanism is validated by numerical results.

关键词： Performance analysis telecommunication traffic Intelligent networks Closed-form solution Bit rate Fluctuations Analytical models Delay Peak to average power ratio laboratories

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DPWSim: A Devices Profile for Web Services (DPWS) Simulator

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IEEE INTERNET OF THINGS JOURNAL 2015年第3期2卷 221-229页

作者： Han, Son N. Lee, Gyu Myoung Crespi, Noel Nguyen Van Luong Heo, Kyoungwoo Brut, Mihaela Gatellier, Patrick Telecom SudParis Inst Mines Telecom Dept Wireless Networks & Multimedia Serv F-91011 Evry France Liverpool John Moores Univ Sch Comp & Math Sci Liverpool L3 3AF Merseyside England Percevio F-75000 Paris France Elect & Telecommun Res Inst Daejeon 305700 South Korea Thales Serv SA Theresis Innovat Ctr F-91767 Palaiseau France

The devices profile for Web services (DPWS) standard enables the use of Web services for resource-constrained devices, main components of the Internet of Things (IoT). DPWS can power the next generation of IoT applications by connecting millions of networked devices and services on the Web. This paper presents a simulator, called DPWSim, to support the use of this technology. DPWSim featuring secure messaging, dynamic discovery, service description, service invocation, and publish-subscribe eventing can be used to prototype, develop, and test products in terms of DPWS communication protocols. It can also support the collaboration among manufacturers, developers, and designers during the new product development process.

关键词： Devices profile for Web services (DPWS) Internet of Things (IoT) simulation Web service

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Heterogeneous RAN slicing resource allocation using mathematical program with equilibrium constraints

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IET COMMUNICATIONS 2022年第15期16卷 1772-1786页

作者： Ma, Tengteng Zhang, Yong Han, Zhu Li, Chen China Telecom Corp Ltd Strategy Dev Inst Beijing Res Inst Beijing Peoples R China Beijing Univ Posts & Telecommun Sch Elect Engn Beijing 100876 Peoples R China Beijing Univ Posts & Telecommun Beijing Key Lab Work Safety Intelligent Monitorin Beijing Peoples R China Univ Houston Elecct & Comp Engn Dept Houston TX USA Kyung Hee Univ Dept Comp Sci & Engn Seoul South Korea

Network slicing is considered to be a key feature of the 5th generation mobile networks. It permits multiple tenants, i.e. mobile virtual network operators, to share virtual resources. However, each tenant only considers the individual slice utility, which leads to unfair resource allocation among tenants. To achieve the aim that the infrastructure provider can fairly allocate virtual resources to tenants, a two-layer resource allocation architecture in a heterogeneous radio access network (RAN) is proposed and it is formulated as a mathematical program with equilibrium constraints (MPEC). The existence of the solution in the lower layer is proved via the properties of the quasi-variational problem, indicating that the MPEC is solvable. Combining the two-layer architecture and successive convex approximation method, a fair algorithm is proposed, which provides fair resource allocation strategies for the infrastructure provider. Compared with the existing static slicing and social optimal methods, the analysis and simulation results confirm that the proposed algorithm weighs the utilities of the total network system and each tenant. In addition, regarding their utilities, the gap between the proposed method and the social optimal is within 5%, which outperforms static slicing.

关键词： telecommunication computing total network system mathematical program quasivariational problem infrastructure provider two-layer resource allocation architecture fair algorithm convex programming resource allocation individual slice utility virtualisation network slicing equilibrium constraints heterogeneous radio access network heterogeneous RAN two-layer architecture cloud computing radio access networks fair resource allocation strategies 5G mobile communication mathematical programming mobile virtual network operators multiple tenants unfair resource allocation virtual resources existing static slicing successive convex approximation method MPEC

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Signaling cost and performance of SIGMA: A seamless handover scheme for data networks

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WIRELESS COMMUNICATIONS & MOBILE COMPUTING 2005年第7期5卷 825-845页

作者： Fu, SJ Atiquzzaman, M Ma, LR Lee, YI Univ Oklahoma Sch Comp Sci Telecommun & Networks Res Lab Norman OK 73019 USA Korea Natl Univ Educ Dept Technol Educ Chungbuk 363791 South Korea

Mobile IP has been developed to handle mobility of Internet hosts at the network layer. Mobile IP (MIP), however, suffers from a number of drawbacks such as requirement of infrastructure change, high handover latency, high packet loss rate, and conflict with network security solutions. In this paper, we describe and evaluate the performance of SIGMA, a Seamless IP diversity-based Generalized Mobility Architecture. SIGMA utilizes multihoming to achieve seamless handover of mobile hosts, and is designed to solve many of the drawbacks of MIP, including requirement for changes in infrastructure. We first evaluate the signaling cost of SIGMA and compare with that of hierarchical Mobile IPv6 (an enhancement of Mobile IP) by analytical modeling, followed by comparison of handover performance of SIGMA and Mobile IPv6 enhancements. Criteria for performance evaluation include handover latency, packet loss, throughput, and network friendliness. Our results indicate that in most cases SIGMA has a lower signaling cost than Hierarchical Mobile IPv6. Moreover, for a typical network configuration, SIGMA has a higher handover performance over Mobile IP Copyright (C) 2005 John Wiley & Sons, Ltd.

关键词： mobile handover SIGMA mobile IP IP diversity signaling cost

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Clustering-based low-complexity resource allocation in two-tier femtocell networks with QoS provisioning

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INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 2017年第4期30卷

作者： Fu, Fengchao Lu, Zhaoming Xie, Yuanbao Jing, Wenpeng Wen, Xiangming Beijing Univ Posts & Telecommun Beijing Key Lab Networks Syst Architecture & Conv Beijing Peoples R China Guangzhou Res Inst China Telecom Guangzhou Guangdong Peoples R China

In this paper, we study the resource allocation problem of the uplink transmission with delay quality-of-service constraints in two-tier femtocell networks. Particularly, to provide statistical delay guarantees, the effective capacity is employed as the network performance measure instead of the conventional Shannon capacity. To make the problem computationally efficient and numerically tractable, we decompose the problem into three subproblems, namely, cluster configuration subproblem, intra-cluster subchannel allocation subproblem and inter-cluster power control subproblem. Firstly, we develop a low-complexity heuristic semi-dynamic clustering scheme, where the delay of the channel state information feedback via backhaul is considered. We model such system in the framework of networked partial observation Markov decision process and derive a strategy to reduce the search range for the best cluster configuration. Then, for a given cluster configuration, the cluster heads deal with subchannel allocation and power control within each cluster. We propose a subchannel allocation scheme with proportional fairness. Thereafter, the inter-cluster power control subproblem is modeled as a set of exact potential games, and a channel quality related pricing mechanism is presented to mitigate inter-cluster interference. The existence and uniqueness of Nash equilibriums for the proposed game are investigated, and an effective decentralized algorithm with guaranteed convergence is designed. Simulation results demonstrate that the proposed algorithms not only have much lower computational complexity but also perform close to the exhaustive search solutions and other existing schemes. Copyright (C) 2015 John Wiley & Sons, Ltd.

关键词： delay QoS effective capacity exact potential game femtocells resource allocation semi-dynamic clustering

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