检索结果-内蒙古大学图书馆

2012 15th International Symposium on Wireless Personal Multimedia Communications, WPMC 2012

作者： Lin, Lin Guo, Caili Feng, Chunyan Wu, Xiaobin Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications BUPT Beijing China

ISBN: (纸本)9789860334074

A new spectrum sensing algorithm-degree of polarization (DoP) sensing algorithm is proposed in this paper. By exploiting a pair of dual-polarized antenna at the receiver, DoP of the received vector signal is estimated and utilized to detect the presence of primary users (PU) based on the polarization characteristics of electromagnetic waves. This method requires no prior information of the PU signals and the channels from PUs to the secondary users (SU). Theoretical analysis of detection probability, false alarm probability and threshold of the proposed algorithm is presented in detail. The theoretical analysis also shows that our algorithm overcomes the noise uncertainty problem. Simulations based on wireless microphone signals considering different SU receiver scenarios are provided to certify the effectiveness of the proposed method. Compared with the energy detector (ED), the maximum-to-minimum ratio eigenvalue (MME) detector and the arithmetic-to-geometric mean (AGM) detector, by applying polarization information signal carries, DoP achieves a better detection performance than AGM, MME and ED with noise uncertainty. © 2012 NiCT.

关键词： Signal detection

来源：评论

学校读者我要写书评

暂无评论

Theoretical polarized channel model and analysis of XPD and polarization correlation under narrowband macrocell environment

Theoretical polarized channel model and analysis of XPD and ...

引用

2012 15th International Symposium on Wireless Personal Multimedia Communications, WPMC 2012

作者： Wu, Xiaobin Guo, Caili Feng, Chunyan Lin, Lin Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing 100876 China

ISBN: (纸本)9789860334074

A theoretical polarized channel model has been proposed by introducing per path polarization characterization based on geometrical depolarization theory. According to the model, polarization array response vector for narrowband macro-cell environment has been derived through intricate geometrical deduction. Mathematical expressions for polarized channel power imbalance XPD (cross polarization discrimination) and polarization correlation have been developed by using VMF (von Mises-Fisher) distribution which characterizes both azimuth and elevation angle. Numerical integration technique is used to analyze the effect of scatterers' angular characteristics including average azimuth angle, average elevation angle and angular spread on XPD and polarization correlation due to the complexity of geometrical deduction. Our analytical results agree well with previous published XPD and polarization correlation measurements and can be used to predict further XPD and polarization correlation characteristics. Analytical results indicate that both XPD and polarization correlation are highly angle-sensitive. © 2012 NiCT.

关键词： Geometry

来源：评论

学校读者我要写书评

暂无评论

Optimization of time-to-trigger parameter on handover performance in LTE high-speed railway networks

Optimization of time-to-trigger parameter on handover perfor...

引用

2012 15th International Symposium on Wireless Personal Multimedia Communications, WPMC 2012

作者： Zhang, Yifan Wu, Muqing Ge, Shunming Luan, Linlin Zhang, Ankang Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing 100876 China

ISBN: (纸本)9789860334074

Handover (HO) is one of the key procedures ensuring that user equipments (UE) can move through the network freely in long term evolution (LTE) systems. The basic idea is to use the handover control parameters, such as HO hysteresis and time-to-trigger (TTT), to enhance the HO success rate. Although TTT can mitigate the ping-pong handover (PPHO) effect, it also causes radio link failure (RLF) due to delayed HO. In this paper, we propose a HO parameter optimization algorithm where TTT is replaced by a statistical threshold value-S threshold, which can reduce the RLF rate. Both HO hysteresis and Sthreshold have been designed and implemented in a dynamic system level simulator and have been discussed for adaptive parameter combinations depending on different UE speed ranges in a high-speed railway scenario. Simulation results show that the optimized algorithm performs better than the traditional A3 event-based HO algorithm in high-speed railway networks. © 2012 NiCT.

关键词： Hysteresis

来源：评论

学校读者我要写书评

暂无评论

Joint pricing and power control for OFDMA femtocell networks using stackelberg game

Joint pricing and power control for OFDMA femtocell networks...

引用

2012 15th International Symposium on Wireless Personal Multimedia Communications, WPMC 2012

作者： Zhang, Jingjing Zhao, Zhenmin Li, Wei Liu, Zhen Xin, Liang Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing 100876 China

ISBN: (纸本)9789860334074

In this paper we formulate to resolve the distributed power control problem in the two-tier OFDMA femtocell networks. The network structure is comprised of the macrocells and each macrocell is further underlaid with several femtocells. The problem is formulated as a Stackelberg game with the macrocell base stations as the leaders and the femtocell access points as the followers in order to obtain the utility maximization of them. Then, the Stackelberg equilibrium for the proposed game is evaluated. It is established to exist and be unique under the proposition of an effective distributed interference price bargaining algorithm. Experimental results show that the proposed power control scheme is effective in improving the outage and throughput performance of macrocell users while the effects on femtocell users are acceptable. © 2012 NiCT.

关键词： Femtocell

来源：评论

学校读者我要写书评

暂无评论

Analysis on preference patterns of ADSL users

引用

Journal of China Universities of Posts and Telecommunications 2012年第SUPPL. 2期19卷 73-79页

作者： Guo, Min-Jie Liu, Peng Liu, Fang Yang, Jie Lei, Zhen-Ming Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing 100876 China Institute of Food and Agricultural Standardization China National Institute of Standardization Beijing 100088 China

The aim to raise customer loyalty in telecom market requires an emphasis on one-to-one marketing and personalized services. To this end, it is essential to understand individual customer preferences for services. In this paper an improved fast hierarchical clustering algorithm (IFHCA) is proposed firstly. Then a method for identifying dial-up user preferences based on IFHCA is presented, in order to discover the pattern of users' preferences and recommend the most appropriate services. Finally, this paper analyses the relationship between users' preferences with on-line duration and traffic. Experiment result shows that IFHCA is of advantages such as analyzing on preference patterns of asymmetric digital subscriber line (ADSL) users accurately, lower time complexity than the classical hierarchical clustering algorithm (CHCA) to mining large dataset efficiently. Besides, the result is provided for selective management and commercial package customization. © 2012 The Journal of China Universities of Posts and Telecommunications.

关键词： Digital subscriber lines

来源：评论

学校读者我要写书评

暂无评论

A novel adjustable harmonic rejection mixer for cognitive radio

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

引用

2012 19th International Conference on Telecommunications, ICT 2012

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

ISBN: (纸本)9781467307475

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 300dB for the required harmonics, and the AHRM uses as few operation-paths as possible to save power consumption. © 2012 IEEE.

关键词： Cognitive radio

来源：评论

学校读者我要写书评

暂无评论

A new Tomlinson-Harashima precoding scheme based on RVQ feedback with fewer bits

A new Tomlinson-Harashima precoding scheme based on RVQ feed...

引用

2012 IEEE 14th International Conference on Communication Technology, ICCT 2012

作者： Liu, Cuijie Wu, Muqing Feng, Zheng Lu, Guoxian Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781467321013

Tomlinson-Harashima precoding exceeds traditional linear precoding system with higher sum rate and lower bit error rate in high signal-to-noise ratio region. In this paper, a novel THP scheme based on limited feedback for Multi-user MIMO system is studied. Based on limited feedback bits, our proposed optimized THP scheme with a modified receiver, which needs feedback channel direction information only, gets the same performance as original system with perfect channel amplitude information (CMI) feedback, and about 3-4dB gains are obtained compared with no CMI feedback situation. Our analysis and the validity of the optimization algorithm are verified by simulation results. Without CMI feedback, the proposed scheme has cut down feedback overheads significantly in THP precoding system which is essential for its implementation for the next generation system. At the same time, the conclusion that channel vector quantization excels to unitary precoding codebook in THP scheme has also been drawn in this paper. © 2012 IEEE.

关键词： Bit error rate

来源：评论

学校读者我要写书评

暂无评论

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

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

引用

2012 19th International Conference on Telecommunications, ICT 2012

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

ISBN: (纸本)9781467307475

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. © 2012 IEEE.

关键词： Orthogonal frequency division multiplexing

来源：评论

学校读者我要写书评

暂无评论

Design of wireless sensor management platform based on embedded ARM

Design of wireless sensor management platform based on embed...

引用

2011 International Conference on Mechanical Engineering, Materials and Energy, ICMEME 2011

作者： Song, Yang Wu, Muqing Jia, Kai Laboratory of Network System Architecture and Convergence Beijing University of Post and Telecommunications Beijing China

ISBN: (纸本)9783037853405

Wireless Sensor network is receiving more widely appreciate because of its great prospect. But a variety of sensors need a unified mobility management platform. This paper considers this problem, proposes and implements a wireless sensor management platform which can control a variety of sensors and transfer the collected data by using wireless technology. Then a testing wireless network is built to test the performance of this mobile platform. The test result proves that this platform has the ability of manage sensors, and has the advantages of mobility and portability. © (2012) Trans Tech Publications, Switzerland.

关键词： Wireless sensor networks

来源：评论

学校读者我要写书评

暂无评论

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

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

引用

2012 15th International Symposium on Wireless Personal Multimedia Communications, WPMC 2012

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

ISBN: (纸本)9789860334074

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. © 2012 NiCT.

关键词： Forecasting

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：