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IEEE Vehicular Technology Conference

作者： Sixing Yin Zhaowei Qu Lihua Li Beijing Key Laboratory of Network System Architecture and Convergence Beijing China Beijing University of Posts and Telecommunications Beijing China

In this paper, we focus on a cellular network with a energy-constrained unmanned aerial vehicle (UAV), which serves as a relay for all the users to improve their uplink rates via cooperative communication. Uplink resource allocation in terms of power and time allocation among users is investigated to optimize the uplink sum-rate. By leveraging the local search strategy, the sum-rate optimization problem is decomposed into two subproblems, i.e., energy allocation and time allocation. We derived the optimal solution for both amplify-and-forward (AF) and decode-and-forward (DF) protocols with in-depth analysis. Numerical results show that path loss exponent has non-trivial impact on the sum-rate while higher energy replenishment rate of the UAV relay brings little performance gain. In addition, location of the UAV is also non-negligible and the cellular network can significantly benefit from proper deployment of the UAV relay.

关键词： Resource management Cellular networks Relays Protocols Uplink Unmanned aerial vehicles Linear programming

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Power Control and Trajectory Design for UAV-assisted Communications

Power Control and Trajectory Design for UAV-assisted Communi...

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IEEE Vehicular Technology Conference

作者： Sixing Yin Jing Tan Lihua Li Zhaowei Qu Beijing Key Laboratory of Network System Architecture and Convergence Beijing China Beijing University of Posts and Telecommunications Beijing Beijing CN

In this paper, we consider a multiuser downlink communication system, where ground users are served by a UAV base station flying on an aerial plane. For the sake of computational complexity and energy economy, we propose a polygonal-line trajectory for the UAV base station and each ground user is served one by one while the UAV base station is travelling along one of the line segments on the trajectory. With the polygonal-line trajectory, joint optimization for power control and trajectory design for the UAV base station is investigated to maximize total capacity of all the ground users. Such a problem is decomposed into three subproblems for single-user downlink power profile, transmission energy allocation and waypoints location selection, respectively, and solved via alternate optimization, with which one of the three subproblems is solved given solutions to the other two. Simulation results show that the proposed scheme with optimized power profile and trajectory for the UAV base station outperforms two baselines. We also show that trajectory design significantly impact the system performance and is indispensable in UAV-assisted communications.

关键词： Base stations Trajectory Downlink Resource management Unmanned aerial vehicles Optimization

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Orthogonal Polarizations Based Channel Estimation for Dual-polarized Massive MIMO Under Pilot Contamination

Orthogonal Polarizations Based Channel Estimation for Dual-p...

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IEEE International Conference on Communications in China Workshops (ICCC)

作者： Li Han Fangfang Liu Chunyan Feng Shulun Zhao Beijing Laboratory of Advanced Information Networks Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781538670125;9781538670118

Pilot contamination limits the accuracy of channel state information (CSI). In this paper, we propose an orthogonal polarizations based channel estimation algorithm in multi-cell multi-user dual-polarized massive multiple-input multiple-output (MIMO) system. The algorithm exploits orthogonal polarizations effectively reduce the mean square error (MSE) under pilot contamination. Meanwhile, for the high complexity of the minimum mean square error (MMSE) channel estimation, the algorithm uses unbiased estimation for the combination term of interference caused by pilot contamination and the noise. Then we deduce and evaluate the approximate MSE analytical expression of the proposed channel estimation. Finally, the simulation results show that the proposed algorithm is simpler than the MMSE estimation, and more practical than least squares (LS) channel estimation.

关键词： Channel estimation Contamination Antennas Estimation MIMO communication Covariance matrices Partial transmit sequences

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Fast Software-based Table-less Algorithm for CRC Generation

Fast Software-based Table-less Algorithm for CRC Generation

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International Symposium on Wireless Personal Multimedia Communications (WPMC)

作者： Mucong Chi Dazhong He Jun Liu Beijing Laboratory of Advanced Information Networks and Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781538657584;9781538657577

This paper proposes a software-based CRC algorithm, which can be applied to CRCs with check values of different lengths. The proposed algorithm can be implemented by shift and XOR operations, and no look-up tables are needed. Therefore, it is suitable for processors with limited memory resources. Compared with table-based CRC algorithms, the proposed algorithm takes more instructions; however, the memory accesses are reduced significantly. As a result, for CRCs with specific generator polynomials, the implementation of the proposed algorithm achieves a high throughput. In the best cases, the proposed algorithm is 29% faster than the Sarwate algorithm for 16-bit CRC generation, and 45% faster than the Slicing-by-4 algorithm for 32-bit CRC generation. Furthermore, for 64-bit CRC generation, the proposed algorithm quadruples the throughput of the Slicing-by-4 algorithm at best.

关键词： Generators Throughput Wireless communication Program processors Software algorithms Multimedia communication Table lookup

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How to Insure Reliability and Delay in Multi-controller Deployment 5th

How to Insure Reliability and Delay in Multi-controller Depl...

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5th International Conference on Geo-Spatial Knowledge and Intelligence, GSKI 2017

作者： Cui, Hongyan Yu, Tao Zheng, Lili Wang, Tao Zhang, Guoping Xia, Zongguo Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing100876 China Institute of Network Science and Cyberspace Tsinghua University Beijing100084 China The China Academy of Corporate Governance and Business School Nankai University Tianjin300071 China University of Massachusetts Beijing University of Posts and Telecommunications Boston United States

ISBN: (纸本)9789811308925

In this paper, we researched the multi-controller deployment problem. Because the switch is completely dependent on the controller, if a forwarding plane failure happens, it may lead to communication interruption between the switch and its controller, the switch will become a "headless fly", so ensuring the reliability of the communication between the switch and its controller is necessary. Because the controller and its management within the domain of the exchange of communications will be very frequent, we want to ensure reliability while making the delay between the controller and the switch become short. Therefore, our algorithm mainly considerate the following two aspects: (1) Increase the communication reliability between the switch node and the controller node. (2) Minimize the delay between the controller and the switch, that is, minimize the average delay between the controller and the switches which under its management. The concrete implementation is divided into the following steps: First, model the network, consider the stability of the forwarding plane and the delay between the switch and the controller to establish the optimization target. And then propose a two-stage algorithm. Finally, perform the simulation on the real network topology. The results of the test show that the solution is working and functional. © 2018, Springer Nature Singapore Pte Ltd.

关键词： Controllers

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Polarization Modulation based Phase Noise Cancellation for Massive MIMO-OFDM systems

Polarization Modulation based Phase Noise Cancellation for M...

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International Symposium on Personal, Indoor, and Mobile Radio Communications

作者： Yao Nie Chunyan Feng Fangfang Liu Caili Guo Huan Wu Beijing Key Laboratory of Network System Architecture and Convergence Beijing Laboratory of Advanced Information Networks Beijing University of Posts and Telecommunications Beijing China 100876

ISBN: (纸本)9781538660102

In massive multiple-input multiple-output (MIMO) uplink systems, phase noise introduced by oscillators can cause severe performance loss. It leads to common phase error and inter-carrier interference in massive MIMO-OFDM uplink. To solve the issue, a novel phase noise cancellation scheme based on polarization modulation is proposed. We first introduce the polarization modulation (PM) exploited in massive MIMO-OFDM uplink. Then, by exploiting zero-forcing detection, we analyze ICI and the distribution of the transformed noise. Furthermore, we demonstrate that phase noise can be asymptotically cancelled and only the transformed additive white Gaussian noise exists as the number of antennas at the base station is very lager. Moreover, we derive the instantaneous signal-to-noise ratio (SNR) on each subcarrier and analyze the ergodic capacity. The simulation results show that the proposed scheme can effectively mitigate phase noise and achieve a higher ergodic capacity.

关键词： MIMO MIMO-OFDM SNR

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SOCIAL-GUIDED REPRESENTATION LEARNING FOR IMAGES VIA DEEP HETEROGENEOUS HYPERGRAPH EMBEDDING

SOCIAL-GUIDED REPRESENTATION LEARNING FOR IMAGES VIA DEEP HE...

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IEEE International Conference on Multimedia and Expo

作者： Yunfei Chu Chunyan Feng Caili Guo Beijing Laboratory of Advanced Information Networks Beijing China Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications China

Representation learning for images is widely recognized as critical to the performance of end tasks such as image classification and cross-modal retrieval. However, most existing methods extract features only from visual content, far from adequate in interpreting semantics latent in images. For social images, there also exists rich social context information, e.g. owners, tags and groups, which provides cues for interpreting semantics. In this paper, we propose a representation learning framework via deep heterogeneous hypergraph embedding (DHHE), considering both visual content and social contexts. In particular, images and their contexts are first represented as a heterogeneous hypergraph, which is then embedded into a low-dimensional space. To incorporate visual information and generalize for unseen images, we learn the mapping from visual content to the semantic space. We conduct experiments with the tasks of classification, cross-modal retrieval and recommendation, which demonstrates the effectiveness of our approach and the merits of social guidance.

关键词： Representation learning Deep learning Hypergraph embedding Social media

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Enhanced Noncontact Vital Signs Detection Method for Slightly Moving Subjects Using Tracks Catching and Parameters Estimation (TCPE)

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Journal of Physics: Conference Series 2019年第2期1237卷

作者： Deken Chen Weijun Hong Yaru Dong Beijing Key Laboratory of Network System Architecture and Convergence Beijing Laboratory of Advanced Information Network Beijing University of Posts and Telecommunications Beijing 100876 China

A novel signal processing method based on track catching and Parameters estimation(TCPE) is proposed to detect the vital signs of slightly moving subjects, which can extract the vital signs of subjects with the influence of Gaussian noise or harmonic interference when the subject is stationary or slightly moving without much body shake. The experiment results show that the proposed method can detect the vital signs of slightly moving subjects with higher accuracy comparing with traditional methods.

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How far can optical access networks support in Multi-access Edge Computing for low delay?

How far can optical access networks support in Multi-access ...

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Optical Fiber Communication Conference, OFC 2018

作者： Xue, Junli Shou, Guochu Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing100876 China

This paper proposes an optical access network scheme to support multi-access edge computing. Experiments in the testbed demonstrate that the round-trip time of optical access networks with 60km fiber and 5hops is belo... 详细信息

ISBN: (纸本)9781943580385

关键词： Edge computing

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An Energy-Efficient User Association Scheme Based on Robust Optimization in Ultra-Dense networks

An Energy-Efficient User Association Scheme Based on Robust ...

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IEEE International Conference on Communications in China Workshops (ICCC)

作者： Chenming Ma Fangfang Liu Zhimin Zeng Shulun Zhao Beijing Key Laboratory of Advanced Information Networks Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781538670125;9781538670118

In ultra-dense networks, due to the diversity of content requested by users, the traffic demand of each user is actually uncertain. User association schemes based on exact traffic demand seem to be outdated. With economic and operational considerations and environmental issues, energy efficiency has now become a key pillar of communication network design. Therefore, we propose an energy-efficient user association scheme based on robust optimization, which improves the stability of association and the energy efficiency of the system. First, a robust optimization model for user association scheme is designed in ultra-dense network deployments. In this model, we construct an uncertainty set of bandwidth to describe the uncertainty of the user traffic demand. Then we solve the association matrix through an iterative user association algorithm to maximize system energy efficiency. The simulation results show that the proposed user association scheme has better energy efficiency performance than the signal to interference plus noise ratio (SINR)-based user association scheme.

关键词： Base stations Optimization Mathematical model Uncertainty Bandwidth Power demand Ultra-dense networks

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