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2012 IEEE 14th International Conference on Communication Technology

作者： Guoxian Lu Muqing Wu Si Zhou Feng Zheng Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications

ISBN: (纸本)9781467321006

In this paper,it is shown that indoor scenarios have the merits of high signal-to-noise ratio and low spatial channel correlation due to less interference and rich *** merits are extremely helpful to Tomlinson-Harashima precoding for multiple-antenna and multi-user ***,a novel Tomlinson-Harashima precoding optimization scheme for multi- user MIMO systems in indoor scenarios has been put *** main idea behind the optimization scheme is to orthogonalize the indoor channel *** BER performance is much better than those of conventional Tomlinson-Harashima precoding and zero-forcing precoding.

关键词： indoor scenarios channel capacity multiple-input multiple-output (MIMO) Tomlinson-Harashima precoding(THP)

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Reversed and Bidirectional Irrigation Methods for Equal-Scale Virtual network Embedding Problem

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China Communications 2012年第11期9卷 127-136页

作者： Huang Tao Liu Jiang Chen Jianya Liu Yunjie Key Laboratory of Universal Wireless Communications of Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 P. R. China Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing 100876 P. R. China

Previous Virtual network (VN) embedding researches mostly focus on developing heuristic algorithms to enhance the efficiency of a physical resource. However, in the equal-scale condition, where the scale of a VN is similar to that of a substrate network, the number of successfully mapped VNs decreases sharply since bottlenecks form easily in the substrate network and disturb the embedding process. In this paper, reversed and bidirectional irrigation methods are proposed for the equal-scale and all-scale conditions. The two proposed methods can be combined with most of the existing heuristic algorithms and map a relatively large number of VNs by reducing the potential substrate bottlenecks. The simulation results show that the reversed irrigation method almost doubles the successfully mapped Revenue than the traditional one in the equal-scale condition. Meanwhile, the bidirectional irrigation method achieves the synthetically best performance in almost all scale conditions.

关键词： VN embedding equal-scale reversed irrigation bidirectional irrigation

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RESEARCH ON CHARACTERIZING CHINESE MULTIMEDIA MESSAGING SERVICE (MMS)

RESEARCH ON CHARACTERIZING CHINESE MULTIMEDIA MESSAGING SERV...

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The 3rd IEEE International Conference on network Infrastructure and Digital Content (2012年第三届IEEE网络基础设施与数字内容国际会议(IEEE IC-NIDC2012))

作者： Chao Dong Bolun Huang Zheng Ma Zhenming Lei Jie Yang Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beiiing 100876 China

Multimedia Messaging Service (MMS) is a standard way to send multimedia messages (MMs),is one of the most popular mobile data services in *** paper analyzed Chinese MMS based on a one-week MMS flow log collected from a commercial ISP covering an entire province in Southern *** the distribution of MMS transmission quantity each day,as well as the transmission speed and inter-arrival time ***,with the curve fitting approach,Weibull model was found to be the most appropriate for the distribution of inter-arrival time,which is able to apply to any further mobile network analyses related to the MMS inter-arrival time.

关键词： Mobile telecommunication network Multimedia messaging service MMs speed distribution Inter-arrival time

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Bandwidth-cost based QoS extension to OSPF

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International Journal of Advancements in Computing Technology 2012年第18期4卷 244-251页

作者： Li, Li Li, Yanjing Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications China International School Beijing University of Posts and Telecommunications China

The emerging of various applications in Internet leads to a technical challenge of quality of service (QoS) guarantee, which is much more critical in the coexisting multi-services scenarios especially. Traditional Open Shortest Path First (OSPF) protocol without QoS consideration has to be improved in order to be utilized efficiently in today's network. In this paper, an on-demand QoS routing mechanism is proposed, which has the main advantage of reaching the QoS demands of the upper layer services while keeping the minimum modification to the existing OSPF protocol. The core of this mechanism is a novel path selection algorithm, which aims to find the best route with minimum cost under the limits of bandwidth requirements. The function and performances of this BW-cost based QoS algorithm are simulated as well as compared to those of the standard Dijkstra algorithm, which is originally used in OSPF, and an existing on-demand QoS algorithm extended to OSPF. Simulation results validate the outstanding performance of the proposed algorithm on load balancing, network utilization and delay: it has the similar ability of load balancing to the existing on-demand QoS algorithm, a little better performance of network utility as well as a great better performance of delay than it, never mention that it exceeds the standard Dijkstra algorithm significantly on each performance parameters listed above.

关键词： Bandwidth

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A novel adjustable harmonic rejection mixer for cognitive radio

A novel adjustable harmonic rejection mixer for cognitive ra...

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International Conference on Telecommunications (ICT)

作者： Zhaoyang Shen Xuekang Sun Caili Guo Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

Currently, how to achieve a flexible RF front-end of cognitive radio becomes a research hotspot. Cognitive user receives the wideband signal which contains the unwanted signals, and suffers from the issue that LO harmonics will down-convert the unwanted signals to the baseband along with the desired baseband signal. In this paper, we propose a novel Adjustable Harmonic Rejection Mixer (AHRM) which utilizes the nonlinearity of mixer and changes the number of operation-paths to satisfy the variable harmonic rejection requirement of cognitive user. The simulation results show that the harmonic rejection ratio of the AHRM can reach about 300 dB for the required harmonics, and the AHRM uses as few operation-paths as possible to save power consumption.

关键词： Harmonic analysis Power harmonic filters Mixers Copper Baseband Radio frequency

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Novel recursive approach for OFDM channel estimation under highly mobile conditions

Novel recursive approach for OFDM channel estimation under h...

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IEEE Conference on Wireless Communications and networking

作者： Qilin Guo Muqing Wu Qinjuan Zhang Xiaofang Hao Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

This paper proposes a novel recursive approach for orthogonal frequency division multiplexing (OFDM) channel estimation over highly mobile channels without any priori channel statistics. The key idea is to decompose each objective channel into the known component and the rest for estimation. The known component is the output of the prior iteration except that the first one is attained in linear time-varying (LTV) model. In each iteration, the rest channel component, obtained by subtracting the known channel component from the original channel, is estimated in generalized complex exponential basis expansion model (GCEBEM). Since the rest component varies much milder than the original channel, both modeling error and inter-carrier interference (ICI) are significantly reduced in GCEBEM-based estimation. Monte Carlo simulations demonstrate the superiority of the proposed approach with a few iterations over the conventional methods under highly mobile conditions.

关键词： Channel estimation OFDM Estimation Mobile communication Signal to noise ratio Accuracy Bit error rate

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New Interference Suppression Precoding Scheme for Downlink Multi-User Multi-Stream MIMO systems

New Interference Suppression Precoding Scheme for Downlink M...

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IEEE Conference on Vehicular Technology (VTC)

作者： Yanzhi Sun Muqing Wu Qilin Guo Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

In this paper, an interference-aware linear precoding scheme, called generalized singular value decomposition based interference suppression precoding (GSVD-ISP), is proposed. GSVD-ISP scheme employs a whitening filter for interference suppression at the receiver and a novel precoder considering other cells' interference for each user at the transmitter. Through slightly loosening the constraint on the signal-to-leakage-plus-noise (SLNR) maximization for multi-user multiple-input multiple-output (MU-MIMO) systems with multiple data streams per user and the use of GSVD algorithms, the proposed scheme decreases redundant computational complexity and reduces the gap between any couple of the stream effective channel gains compared with the original interference-aware enhancement to SLNR precoding scheme-multiuser generalized eigenmode transmission (MGET). Simulation results demonstrate that the proposed GSVD-ISP technique achieves considerable gains in terms of bit error rate (BER) over MGET technique with multi-stream and the traditional interference-aware block diagonalization (BD) scheme while maintaining roughly the same achievable sum-rate.

关键词： Interference Signal to noise ratio MIMO Downlink Bit error rate Covariance matrix

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Cooperative Spectrum Sensing Based on Artificial Neural network for Cognitive Radio systems

Cooperative Spectrum Sensing Based on Artificial Neural Netw...

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International Conference on Wireless Communications, networking and Mobile Computing (WiCom)

作者： Tingting Zhang Muqing Wu Cuijie Liu Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

To improve the performance of spectrum sensing in cognitive radio (CR) network consisting of primary user (PU), secondary user (SU) and fusion center, a cooperative spectrum sensing scheme based on artificial neural network (ANN) is designed. ANN is introduced at every SU to forecast the probability which represents the effect of local sensing. Fusion center uses weighting fusion which regards the probability forecasted as weights to make full use of information of SUs in diverse environment. Simulations prove that the proposed scheme can achieve satisfying probability of false-alarm and detection.

关键词： Sensors Cognitive radio Signal to noise ratio Probability Artificial neural networks Training

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A cross-layer design for video applications based on QoE prediction

A cross-layer design for video applications based on QoE pre...

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International Symposium on Wireless Personal Multimedia Communications (WPMC)

作者： Ying Ju Zhaoming Lu Wei Zheng Xiangming Wen Dabing Ling Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications China

In this paper, we propose a cross-layer design scheme for optimizing resource allocation of video applications based on Quality of Experience (QoE) prediction. A novel mapping model between Peak Signal-to-Noise Ratio (PSNR) and Mean Opinion Score (MOS) based on hyperbolic tangent function is presented to reflect the relation between objective parameters and subjective perceived quality. On the basis of this model, we propose a QoE prediction function and utilize the Particle Swarm Optimization (PSO) method to solve the resource allocation problem. Simulation results show that our QoE-based cross-layer design scheme leads to significant improvements in terms of maximizing user-perceived quality as well as maintaining fairness among users.

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Carrier frequency offset estimation based on data-dependent superimposed training for OFDM systems

Carrier frequency offset estimation based on data-dependent ...

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International Conference on Telecommunications (ICT)

作者： Qinjuan Zhang Muqing Wu Qilin Guo Tingting Zhang Rui Zhang Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

In this paper, we propose a solution to the carrier frequency offset (CFO) estimation based on data dependent superimposed training scheme for Orthogonal Frequency Division Multiplexing (OFDM) systems. The proposed CFO estimation can improve the bandwidth efficiency compared with traditional pilot assistant scheme because it consumes no extra bandwidth for the training sequence is superimposed to the data sequence. The simulations demonstrate that the proposed estimator can approach the performance of the pilot assistant scheme very well in terms of MSE and BER with great bandwidth efficiency improvement. Overall, the proposed solution outperforms the traditional pilot assistant scheme.

关键词： Estimation OFDM Bandwidth Training Channel estimation Receivers Interference

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