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IEEE 24th International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)

作者： Zhang, Zhicai Zhang, Haijun Zhao, Zhenmin Liu, Hui Wen, Xiangming Jing, Wenpeng 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)9781467362351

Femtocells have attracted growing attentions in academia, industry, and standardization forums in recent years. However, most of existing works on femtocell networks are focused on spectrum efficiency and interference mitigation, energy efficiency aspect is neglected. In this paper, we investigate the maximization of energy efficiency of downlink OFDMA dense femtocell networks by efficient resource allocation. To decrease the complexity, joint subchannel allocation and power control are decomposed into two steps. Power control has been modeled as a non-cooperative game, a closed-form best response of transmit power is obtained. Considering fairness and low complexity, a fair time-averaged subchannel allocation metric have been derived out. Based on that, we propose a distributed suboptimal subchannel allocation and optimal power control algorithm. Simulation results show that the proposed algorithm has a low complexity with slight loss of energy efficiency compared with Round-Robin Scheduling and a noncooperative energy-efficient power optimization algorithm.

关键词： Energy efficiency

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Transmission capacity for overlaid wireless networks: A homogeneous primary network versus an inhomogeneous secondary network

Transmission capacity for overlaid wireless networks: A homo...

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2013 International Conference on Communications, Circuits and systems, ICCCAS 2013

作者： Liu, Yang Yin, Changchuan Gao, Jing Sun, Xiaohui Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing 100876 China

ISBN: (纸本)9781479930517

We study the transmission capacity of two overlaid wireless ad hoc networks, where a primary network and a secondary network operate in the same geographic region and share the same spectrum. The primary network has a high priority to access the spectrum and is oblivious of the presence of the secondary network while the secondary network limits its interference to the primary network by controlling the density of its transmitters. Assuming the primary transmitter nodes are distributed as a Poisson point process and the secondary transmitter nodes are distributed as a Matern cluster process, we present an upper and a lower bounds for the transmission capacity of the primary network and that of the secondary network. Numerical results show that the transmission capacity of the primary network and that of the secondary network have a small increment due to the inhomogeneity of the secondary network. © 2013 IEEE.

关键词： Transmitters

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Energy-efficient base station deployment in heterogeneous cellular network with QoS constraint

Energy-efficient base station deployment in heterogeneous ce...

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2013 IEEE 24th International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC Workshops 2013

作者： Yu, Jian Liu, Yang Yin, Changchuan Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing 100876 China

ISBN: (数字)9781479901227

ISBN: (纸本)9781479901227

We investigate the energy efficiency in the downlink of a two-tier heterogeneous cellular network with quality of service consideration. By modeling the distributions of the macrocell and small cell base stations follow two independent homogeneous Poisson point processes, we derive the analytical expressions of the mean achievable rate and the energy efficiency with the assumption that a mobile user connects to the closest BS. In addition, we evaluate the energy efficiency subject to a constraint of the blocking probability. Considering the dynamic variation of the traffic load, we use the numerical results to show that the optimum value of energy efficiency can be reached at determined deployment densities of the macrocells and the small cells, and the blocking probability has a dramatic impact on the optimal base station deployment. © 2013 IEEE.

关键词： Energy efficiency

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Implementation of rate matching with low latency and little memory for LTE turbo code

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Journal of Information and Computational Science 2013年第13期10卷 4117-4125页

作者： He, Suqin Hu, Qiaozhi Zhang, Haijun Department of Computer Science and Technology Beijing University of Chemical Technology Beijing 100029 China Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing 100876 China

In LTE (Long Term Evolution), the high utilization for physical resources is achieved by scheduling suitable number of time frequency resource elements for one user in one subframe. This is supported by the rate matching module that selecting arbitrary number of bits from the turbo coding bit streams. In this paper, a closed-form rate matching implementation method is proposed. It derives an integrated expression which is normalized for the 3 turbo coding streams. This expression sets up a mapping relationship between the bit streams input to and the bit sequence output from rate matching module. Moreover, the expression can be applied to rate de-matching processing in the receiver end. Compared with the existing method, the rate matching method that we proposed generates low latency and requires small memory. © 2013 Binary Information Press.

关键词： Turbo codes

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A hybrid multi-channel based medium access control mechanism for WLAN

A hybrid multi-channel based medium access control mechanism...

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5th IET International Conference on Wireless, Mobile and Multimedia networks, ICWMMN 2013

作者： Wang, Yi Luo, Tao Li, Jianfeng Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing 100876 China

ISBN: (纸本)9781849197267

The evolution of modern communication technologies is steadily advancing the physical layer (PHY) data rate in WLANs. However, because of the current Medium Access Control (MAC) protocols, which allocate the whole channel as a single resource, the overhead of the MAC grows along with the PHY data rates. Ultimately, the data throughput efficiency of the system degrades. This paper puts forward a multi-channel MAC protocol, which argues that the channel should be divided into several separate sub-channels, so that multiple stations can contend for and transmit messages on different sub-channels simultaneously, thereby increasing the throughput of the system. Finally, the multi-channel MAC protocol is compared with the traditional MAC protocol by theoretical analysis and simulation, and the results show that the multi-channel MAC protocol can get a better system throughput.

关键词： Medium access control

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Performance analysis of MapReduce program in heterogeneous cloud computing

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Journal of networks 2013年第8期8卷 1734-1741页

作者： Lin, Wenhui Liu, Jun Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication Engineering Beijing University of Posts and Telecommunications China Technology Research Institute Aisino Corporation Beijing 100195 China

The research of Hadoop is an important part of cloud computing industry, and Hadoop performance research is a key research direction. The Hadoop performance analysis as a basic work can provide important reference for other performance optimization researches. In this paper, based on previous researches of server performance analysis, we propose a node performance measurement method on Hadoop. We describe in detail how to measure the performance value of each node in heterogeneous Hadoop cluster and evaluate measurement results by running MapReduce programs. Meanwhile, the method has also been implemented and evaluated in real-world Hadoop cluster. Experiment results show that the method can accurately measure the performance value of each node. Based on this research, users can have a comprehensive and objective understanding of their own Hadoop cluster and then make optimization and improvement on Hadoop. © 2013 ACADEMY PUBLISHER.

关键词： Cloud computing

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QoS-aware user association based on cell zooming for energy efficiency in cellular networks

QoS-aware user association based on cell zooming for energy ...

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2013 IEEE 24th International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC Workshops 2013

作者： Zhu, Yutao Kang, Tian Zhang, Tiankui Zeng, Zhimin Beijing Key Laboratory of Network System Architecture and Convergence Beijing China Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781479901227

In cellular networks, cell zooming with the variation of the traffic load is considered as one of promising technologies for energy saving. Cells with less traffic load can be turned into sleep mode and the other cells zoom in to ensure the coverage. In this paper, based on the cell zooming, we propose a quality of service (QoS) aware user association scheme (UAS) to reconfigure the cell association for energy saving. In the UAS, we consider the tradeoff between QoS guarantee and energy saving of the networks. The optimization problem of UAS is derived from the network weight matrix and user association matrix. A heuristic iteration algorithm is provided to solve this optimization problem, and then the cells without associated users can be turned off for energy saving. Simulation results show that the proposed UAS can significantly reduce energy consumption and improve the energy efficiency without degrading QoS, especially under the low traffic load. © 2013 IEEE.

关键词： Cells

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Energy-Efficient Transmission Scheme for Mobile Data Gathering in Wireless Sensor networks

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China Communications 2013年第3期10卷 114-123页

作者：刘丹谱张铠麟丁杰 Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications

Energy conservation in Wireless Sensor networks (WSNs) has always been a crucial issue and has received increased attention in the recent years. A transmission scheme for energy-constrained WSNs is proposed in this paper. The scheme, called MIHOP (MIMO and Multi-hop), combines cluster-based virtual MIMO and multi-hop technologies. The multihop mode is employed in transmitting data when the related sensors are located within a specific number of hops from the sink, and the virtual MIMO mode is used in transmitting data from the remaining sensor nodes. We compare the energy consumption of different transmission schemes and propose an algorithm for determining the optimal hop count in MIHOP. A controllable mobile sink that reduces the energy consumed in sensor transmission is also adopted for data collection. The theoretical analysis and the Monte Carlo simulation demonstrate that the proposed scheme significantly outperforms individual virtual MIMO, multi-hop technologies, and double-string networks in terms of energy conservation. The energy consumption levels under the MIHOP scheme are approximately 12.98%, 47.55% and 48.30% less than that under virtual MIMO schemes, multi-hop networks and doublestring networks, respectively.

关键词： wireless sensor networks energyefficiency virtual MIMO multi-hop network mobile sink

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An efficient algorithm for dynamic storage allocation in cloud computing environment

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International Journal of Applied Mathematics and Statistics 2013年第18期48卷 254-262页

作者： Lin, Wen-Hui Lei, Zhen-Ming Liu, Jun Liu, Fang He, Gang Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication Engineering Beijing University of Posts and Telecommunication Beijing 100876 China Technology Research Institute Aisino Corporation Beijing 100195 China

With the development of cloud computing, cloud computing cluster will need to be upgraded or replacing outdated hardware. Therefore, the cluster will evolve from the initial homogenous environment into heterogeneous environments. Hadoop is originally designed to be applied to homogeneous clusters, when the cluster goes heterogeneous, the performance of Hadoop will face a downward trend. This paper addresses the problem of how to improve the performance of Hadoop in heterogeneous environments. We study the evaluation methods of server performance and Hadoop technology. Then we present a method of evaluating node performance in cloud computing environment. Base on this method, we propose an algorithm for dynamic storage allocation that based on node performance evaluation. Experiments show that this algorithm can improve the ratio of data-local map tasks and shorten job runtime in heterogeneous Cloud Computing environment. © 2013 by CESER Publications.

关键词： Cloud computing

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MapReduce optimization algorithm based on machine learning in heterogeneous cloud environment

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The Journal of China Universities of Posts and Telecommunications 2013年第6期20卷 77-87,121页

作者： LIN Wen-hui LEI Zhen-ming LIU Jun YANG Jie LIU Fang HE Gang WANG Qin Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications School of Information Engineering Beijing University of Posts and Telecommunications Technology Research Institute Aisino Corporation School of Electronic Engineering Beijing University of Posts and Telecommunications

We present an approach to optimize the MapReduce architecture, which could make heterogeneous cloud environment more stable and efficient. Fundamentally different from previous methods, our approach introduces the machine learning technique into MapReduce framework, and dynamically improve MapReduce algorithm according to the statistics result of machine learning. There are three main aspects： learning machine performance, reduce task assignment algorithm based on learning result, and speculative execution optimization mechanism. Furthermore, there are two important features in our approach. First, the MapReduce framework can obtain nodes＇ performance values in the cluster through machine learning module. And machine learning module will daily calibrate nodes＇ performance values to make an accurate assessment of cluster performance. Second, with the optimization of tasks assignment algorithm, we can maximize the performance of heterogeneous clusters. According to our evaluation result, the cluster performance could have 19% improvement in current heterogeneous cloud environment, and the stability of cluster has greatly enhanced.

关键词： cloud computing MapReduce machine learning heterogeneity

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