检索结果-内蒙古大学图书馆

International Symposium on Wireless Communication systems (ISWCS)

作者： Wuqiong Ding Xiangming Wen Zhaoming Lu Wenpeng Jing Yan Zeng Beijing Key Laboratory of Network System Architecture and Convergence Beijing Advanced Innovation Center for Future Internet Technology Beijing Laboratory of Advanced Information Networks Beijing Beijing University of Posts and Telecommunications Beijing China

LTE on unlicensed bands (LTE-U), which is a promising way to meet the increasing mobile data demand, has attracted world-wide interests. However, the fair coexistence of LTE-U and WLAN is a critical issue to be solved. In this paper, we devise a semi-distributed channel access approach for LTE-U in dense deployed scenario to improve its capacity and achieve fair coexistence with WLAN. Specifically, the basic listen-before-talk (LBT) mechanism is employed to guarantee the fairness for WLAN, which is similar with the medium control access (MAC) protocol of WLAN. However, in order to decrease the high collision probability at heavy traffic load, a coalition strategy is introduced, in which the LTE-U base stations (BSs) would form into groups, and each group would contend for accessing the channel as one entity. This will effectively reduce the number of stations contending for accessing the channel and the collision probability as a result. In particular, in order to obtain the coalition solution, the cooperative game theory is introduced, and a low-complexity coalition formation algorithm is proposed based on the concept of recursive core in cooperative game. Simulation results verify the effectiveness of the proposed channel access approach, especially improving the LTE-U capacity and ensuring the fairness between LTE-U and WLAN.

关键词： Wireless LAN Games Interference IEEE 802.11 Standard Throughput Signal to noise ratio Mobile communication

来源：评论

学校读者我要写书评

暂无评论

An improved dbf processor with a large receiving antenna for echoes separation in spaceborne SAR

引用

Progress In Electromagnetics Research C 2016年 67卷 49-57页

作者： Mo, Hongbo Xu, Wei Zeng, Zhimin School of Information and Communication Engineering Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing100876 China Spaceborne Microwave Remote Sensing System Department Institute of Electronics Chinese Academy of Sciences Beijing100190 China

Digital beamforming (DBF) on receive in elevation with a large receiving antenna will be widely adopted in future spaceborne synthetic aperture radar (SAR) missions to improve system performances. Furthermore, DBF can be used to separate echoes corresponding to different sub-pulses in some novel spaceborne SAR imaging modes. This paper proposes an improved DBF processor with a large receiving antenna for separating echoes. The proposed DBF processor includes three important parts: multiples sharp receiving beam generation, range compression and null steering. Compared with the conventional DBF processor in spaceborne SAR, the proposed DBF processor can separate echoes with better performances. Simulation results on point targets demonstrate validity of the proposed DBF processor. © 2016, Electromagnetics Academy. All rights reserved.

关键词： Receiving antennas

来源：评论

学校读者我要写书评

暂无评论

A 3-D Polarization Quadrature Amplitude Modulation Method and Constellation Mapping

引用

China Communications 2015年第10期12卷 16-26页

作者： SUN Xuehong ZHANG Haiying ZENG Zhimin GUO Caili Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication EngineeringBeijing University of Posts and Telecommunications Key Laboratory of Intelligent Sensing for Desert Information School of Physics Electrical EngineeringNingxia University

As a new three-dimensional(3-D)modulation,Polarization Quadrature Amplitude Modulation(PQAM) can be regarded as the combination of Pulse amplitude modulation(PAM) and Quadrature Amplitude Modulation(QAM) *** can better improve the digital communication efficiency and reduce the Symbol error rate(SER) of the system than one-dimensional or two-dimensional modulation *** to design a feasible constellation is the most concerned problem of PQAM *** paper first studies the relationship between the SER theoretical value of PQAM and the distribution of M and N,proposes a new M,N allocation ***,a new and straightforward design method of constructing higher-level 3-D signal constellations,which can be matched with the PQAM,and the constellation can divided into three different structures according to the ary for ***,the simulation results show that:in PQAM system,the modulation scheme and the constellation mapping scheme are proposed in this paper which can effectively reduce the system SER and improve the anti-noise performance of the system.

关键词： polarization quadrature amplitude modulation minimum euclidean distance symbol error probability 3-D constellation

来源：评论

学校读者我要写书评

暂无评论

Software Defined Multi-OLT Passive Optical network For Flexible Traffic Allocation

Software Defined Multi-OLT Passive Optical Network For Flexi...

引用

International Symposium on Optoelectronic Technology and Application 2016(OTA 2016)——Conf.15 Optical Communication and Optical network

作者： SHIZONG Zhang RENTAO Gu YUEFENG Ji JIAWEI Zhang HUI Li Beijing Key Laboratory of Network System Architecture and Convergence School of Information and Communication EngineeringBeijing University of Posts and Telecommunications State Key Lab of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications

With the rapid growth of 4G mobile network and vehicular network services,mobile terminal users have increasing demand on data sharing among different radio remote units(RRUs) and roadside units(RSUs)

ISBN: (纸本)9781510607743

关键词： Passive optical network Software defined networking Bandwidth optimization Passive optical networks access network wavelengths Traffic core network control surfaces Building construction architecture bandwidth on demand Bandwidth

来源：评论

学校读者我要写书评

暂无评论

QoS-priority based load balancing algorithm for LTE systems with mixed users

引用

The Journal of China Universities of Posts and Telecommunications 2015年第3期22卷 9-17页

作者： Chuai Gang Meng Fanfan Sun Li School of Information and Communication Engineering Beijing University of Posts and Telecommunications Key Laboratory of Universal Wireless Communications Ministry of EducationBeijing University of Posts and Telecommunications Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications

Focusing on the load balancing problem among multi-cells in long term evolution （LTE） networks with mixed users, a new multi-objective optimization modeling strategy, which integrates the guaranteed bit rate （GBR） and the best effort （BE） users, was proposed. In consideration of quality of service （QoS） priorities of different users, a decomposition method was presented to solve the original model. Derivations such as applying Lagrange multiplier method, sub-optimal solutions for mixed users were deduced. Based on derived solutions, including resource allocation schemes, a practical multi-objective load balancing algorithm jointly dealing with mixed users was given. Simulation shows a significant improvement of GBR users＇ satisfaction level and BE users＇ throughput in LTE networks by using the proposed algorithm.

关键词： long term evolution system quality of service mixed users multi-objective optimization load balancing resource allocation

来源：评论

学校读者我要写书评

暂无评论

QoS-aware transmission management for energy harvesting wireless sensor networks

QoS-aware transmission management for energy harvesting wire...

引用

International Conference on Telecommunications (ICT)

作者： Dan Liu Yan Sun Yuanyuan Yao Changchuan Yin Beijing Key Laboratory of Network System Architecture Convergence Beijing University of Posts and Telecommunications China School of Electronic Engineering and Computer Science Queen Mary University of London London UK

Wireless sensor networks (WSNs) are widely deployed in many fields nowadays. However, the limited energy storage ability of sensor nodes causes great detrimental effect on the performance of the WSNs. Energy harvesting has been proved as one of the promising ways to replenish the energy constrained sensors for prolonging WSNs lifetime. Another exacerbated problem introduced by non-uniform energy distribution and nonoptimal energy management in WSNs also causes great challenge to WSNs. For realizing the efficient energy utilization and improving the performance of energy harvesting enabled WSNs, two transmission management schemes, Markov decision based packets aggregation allocation (MDPA) and partial Kalman filter with best-match aggregation (PKBPA), are proposed respectively in this paper. MDPA focuses on the node's own energy capabilities to decide the packets number for aggregation, while PKBPA decides the number of packets to be aggregated and transmitted based on the estimated energy state information of the node and its next hop. Simulation results show that the PKBPA scheme outperforms other schemes, especially when the energy is insufficient for the packets transmission.

关键词： Wireless sensor networks Buffer storage Energy harvesting Quality of service Resource management Markov processes Energy states

来源：评论

学校读者我要写书评

暂无评论

A bio-inspired approach for network selection in dense heterogeneous networks

A bio-inspired approach for network selection in dense heter...

引用

IEEE Asia Pacific Conference on Wireless and Mobile, APWiMob 2015

作者： Chen, Yawen Wen, Xiangming Lu, Zhaoming Shao, Hua Cheng, Jie Xi, Zeguo Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781479982905

The emerging dense heterogeneous networks comprising different types of small cells enable consumers to employ multiple radio access technologies to communicate. In such a dymica network environment, development of robust and self-adaptive network selection mechanisms is required to satisfy the growing demand on ubiquitous network access. Besides, the energy consumed at wireless interface accounts for the great proportion of the total energy consumption of user devices and the battery lifetime has become a important factor affecting quality of experience (QoE). Hence in this paper, we propose an adaptive network selection approach where each user autonomously choose desired wireless network interface that offers the best energy-quality tradeoff. For this purpose, we adopt an attractor selection model, which is developed from autonomous and adaptive behavior of biological systems. The high adaptability to fluctuating network environment and the simple control rules allow users to dynamically select the best network that provide satisfactory QoE while achieve a acceptable device battery lifetime. © 2015 IEEE.

关键词： Quality of service

来源：评论

学校读者我要写书评

暂无评论

Opportunistic energy harvesting and energy-based opportunistic spectrum access in cognitive radio networks 1

引用

10th International Conference on Cognitive Radio Oriented Wireless networks, CROWNCOM 2015

作者： Yao, Yuanyuan Song, Xiaoshi Yin, Changchuan Huang, Sai Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (数字)9783319245409

ISBN: (纸本)9783319245393

The performance of large-scale cognitive radio (CR) networks with secondary users self-sustained by opportunistically harvesting radio-frequency (RF) energy from nearby primary transmissions is investigated. Using an advanced RF energy harvester, a secondary user is assumed to be able to collect ambient primary RF energy as long as it lies inside the harvesting zone of an active primary transmitter (PT). A variable power (VP) transmission mode is proposed, and a simple energybased opportunistic spectrum access (OSA) strategy is considered, under which a secondary transmitter (ST) is allowed to transmit if its harvested energy is larger than a predefined transmission threshold and it is outside the guard zones of all active PTs. The transmission probability of the STs is derived. The coverage probabilities and the throughputs of the primary and the secondary networks, respectively, are characterized. The throughput can be increased by as much as 29%. Simulation results are provided to validate our analysis. © Institute for Computer Sciences, Social Informatics and Telecommunications Engineering 2015.

关键词： Cognitive radio

来源：评论

学校读者我要写书评

暂无评论

Cooperative base station operation for green dense heterogeneous networks

Cooperative base station operation for green dense heterogen...

引用

IEEE Asia Pacific Conference on Wireless and Mobile, APWiMob 2015

作者： Chen, Yawen Wen, Xiangming Lu, Zhaoming Shao, Hua Cheng, Jie Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781479982905

Dense heterogeneous networks are deployed for future wireless communication to meet the explosively increasing traffic demand. However, the network densification leads to a great amount of energy consumption especially the operation energy consumption. In this paper, we consider cooperative Base station (BS) operation in downlink dense heterogeneous networks consisting of one macro BS and several small cell BSs (SBSs). Two sleep modes operating at different time scales are proposed to save energy based on the features of wireless traffic, i.e., traffic is rather stable in long term but fluctuates in short term. When work in deep sleep mode, physical infrastructure of SBSs like baseband and circuits are switched off. In opportunistic sleep mode, SBS optimally switch off some antennas and associated physical components and perform cooperative transmission for users. The proposed cooperative BS sleep strategy for dense heterogeneous networks takes both traffic features and cooperation transmission into account, and can achieve great energy saving while guarantee the quality of service (QoS) of users. © 2015 IEEE.

关键词： Energy conservation

来源：评论

学校读者我要写书评

暂无评论

An efficient and QoS-aware virtual network resource migration algorithm

An efficient and QoS-aware virtual network resource migratio...

引用

IEEE International Conference on Computer and Communications, ICCC 2015

作者： Ma, Lu Lu, Zhaoming Yu, Bangchao Wang, Luhan Wen, Xiangming Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications Beijing China

ISBN: (纸本)9781467381253

In this paper, a joint reducing energy consumption and improving quality of service scheme for the migration of virtual network resources is proposed. This migration algorithm reflects the state of the virtual network resources dynamically, and the algorithm consists of two parts: Energy-efficient Module and QoS Module. Each Module is responsible for a specific function. The Energy-efficient Module is responsible for the energy consumption of servers, and the QoS Module is responsible for the quality of network service, and it can optimize the target nodes with the relative cost of migration. The efficient and QoS-Aware migration algorithm take the energy consumption and the quality of service into account. The simulation results show that the proposed algorithm can reduce energy consumption to the servers, improve the quality of experience, reduce the latency and achieve the objectives of managing of virtual network quickly and easily. © 2015 IEEE.

关键词： Quality of service

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：