检索结果-内蒙古大学图书馆

IEEE Internatonal Conference on mobile Adhoc and Sensor Systems (MASS)

作者： Weihuang Fu Bin Xie Dharma P. Agrawal Anup Kumar OBR Center of Distributed and Mobile Computing Department of Computer Science University of Cincinnati Cincinnati OH USA Computer Engineering and Computer Science Department2 University of Louisville Louisville KY USA

Unlike ad hoc networks where traffic is randomly distributed among every pair of nodes, the traffic in wireless mesh networks (WMNs) is predominantly toward or from the Internet Gateways (IGWs)for Internet services. Due to this, interference and collision are more serious in the Mesh Router (MRs) closer to the IGWs and the Internet throughput of the network is limited by the number of orthogonal channels and radios of the IGW. In this paper, we propose a channel assignment scheme which exploits a tree-based topology in WMNs and implements a heuristic channel assignment algorithm, aiming to achieve the maximal Internet throughput. The channels are sequentially assigned level by level in the tree, starting from the IGW. The simulation results show that the network using this scheme achieve the Internet throughput close to the maximal capacity of IGW.

关键词： Wireless mesh networks IP networks Throughput Telecommunication traffic Web and internet services Ad hoc networks Interference Road accidents Network topology Heuristic algorithms

来源：评论

学校读者我要写书评

暂无评论

Performance of UWB Receiver with Cognitive Channel Allocation and Rake Optimization

Performance of UWB Receiver with Cognitive Channel Allocatio...

引用

International Conference on Cognitive Radio Oriented Wireless Networks and Communications

作者： C. Ghosh D. P. Agrawal A. Chakraborty Center for Distributed and Mobile Computing Department of Computer Science University of Cincinnati Cincinnati OH USA Siemens AG Corporate Research and Development Princeton NJ USA

ISBN: (纸本)9781424408146;1424408156

The design of a UWB receiver for increasing data rate applications has created challenging interest in the research community. Code Division Multiple Access (CDMA) is used as a multiple access technique in our UWB receiver architecture based on the assignment of different spreading codes to a singe user. Since UWB signals are multipath rich, we have used Orthogonal frequency division multiplexing (OFDM)-UWB. OFDM provides better multipath resolution than the single carrier UWB. The addition of iterative Turbo decoding further improves the performance of the receiver in such scenario. Our research work is focused on the performance evaluation of UWB receivers. Thus, rake filtering is also included for optimal multipath diversity which improves the overall performance. Cognitive Radio (CR) plays a vital role in our cross-layer UWB receiver architecture where it exchanges information with the physical layer for probable channel conditions before allocating links dynamically for its data transmission. The receiver performance is evaluated in terms of bit error rate (BER) in severe multipath faded channels with exponential power delay profile. The joint optimization of a strategic selection of propagation paths for the Rake receiver is analyzed using mixed integer programming and simulated using the GLPK tool.

关键词： RAKE receivers Channel allocation Multiaccess communication OFDM Bit error rate Signal resolution Iterative decoding Filtering Cognitive radio Chromium

来源：评论

学校读者我要写书评

暂无评论

Impact of bursty error rates on the performance of wireless local area network (WLAN)

引用

Ad Hoc Networks 2006年第5期4卷 651-668页

作者： Yin, Jun Wang, Xiaodong Agrawal, Dharma P. OBR Center of Distributed and Mobile Computing Department of ECECS University of Cincinnati Cincinnati OH 45221-0030 United States

With an increasing popularity of DCF based wireless LAN, the modeling of 802.11 distributed coordination function (DCF) has attracted lots of research attention. Existing analysis of 802.11 DCF has been focused on the determination of the throughput and the packet delay under saturated traffic and ideal channel conditions. Although some recent papers address the saturated performance under a simple uniform error model, they can hardly capture the impact of bursty characteristics of wireless fading on the performance of 802.11 DCF. This paper presents exact formulae for the throughput and the delay in DCF for various traffic conditions when either saturated or unsaturated traffic load is present. A two-state Markov channel model is incorporated to present the bursty characteristics of channel errors. With our analysis, the impact of bursty channel error on unsuccessful transmission probability and the DCF performance can be determined. The results of our analytical framework reveal that the four-way handshaking scheme does not improve throughput substantially for light traffic load. However, for heavy traffic load, the four-way handshaking scheme is advantageous as compared to the basic access scheme. Also, extensive simulation is done to substantiate the accuracy of our analytical model. © 2005 Elsevier B.V. All rights reserved.

关键词： Wireless telecommunication systems

来源：评论

学校读者我要写书评

暂无评论

On-demand reliable medium access in sensor networks 06

On-demand reliable medium access in sensor networks

引用

WoWMoM 2006: 2006 International Symposium on a World of Wireless, mobile and Multimedia Networks

作者： Biswas, Ratnabali Jain, Vivek Ghosh, Chittabrata Agrawal, Dharma P. OBR Center for Distributed and Mobile Computing Department of ECECS University of Cincinnati

ISBN: (纸本)0769525938

A wireless sensor network typically consists of a dense deployment of sensor nodes to achieve higher resolution and better network coverage. Having a dense network increases the fault-tolerance and robustness of the system. However, if not properly handled, it can lead to more collisions during transmission and also network congestion. Furthermore, wireless communication is inherently unpredictable and error-prone. Hence, it is imperative to design an efficient medium access control (MAC) protocol that facilitates guaranteed delivery of data over unreliable wireless links. In this paper, we have designed an on-demand reliable MAC (RMAC) protocol that enables timely delivery of data. We have demonstrated its superior performance over existing reliability-enforcing approaches in terms of reliability, latency, scalability and energy-efficiency. © 2006 IEEE.

关键词： Telecommunication networks

来源：评论

学校读者我要写书评

暂无评论

Attribute allocation and retrieval scheme for large-scale sensor networks

Attribute allocation and retrieval scheme for large-scale se...

引用

作者： Biswas, Ratnabali Chowdhury, Kaushik Agrawal, Dharma P. OBR Research Center for Distributed and Mobile Computing Department of ECECS University of Cincinnati Cincinnati OH 45221-0030 United States

Wireless sensor network is an emerging technology that enables remote monitoring of large geographical regions. In this paper, we address the problem of distributing attributes over such a large-scale sensor network so that the cost of data retrieval is minimized. The proposed scheme is a data-centric storage scheme where the attributes are distributed over the network depending on the correlations between them. The problem addressed here is similar to the Allocation Problem of distributed databases. In this paper, we have defined the Allocation Problem in the context of sensor networks and have proposed a scheme for finding a good distribution of attributes to the sensor network. We also propose an architecture for query processing given such a distribution of attributes. We analytically determine the conditions under which the proposed architecture is beneficial and present simulation results to demonstrate the same. To the best of our knowledge, this is the first attempt to determine an allocation of attributes over a sensor network based on the correlations between attributes. © Springer Science+Business Media, LLC 2006.

关键词： Wireless telecommunication systems

来源：评论

学校读者我要写书评

暂无评论

Concurrent packet reception bounds of on-demand MAC protocols for multiple beam antennas

Concurrent packet reception bounds of on-demand MAC protocol...

引用

2006 IEEE 17th International Symposium on Personal, Indoor and mobile Radio Communications, PIMRC

作者： Jain, Vivek Agrawal, Dharma P. OBR Center for Distributed and Mobile Computing Department of ECECS University of Cincinnati Cincinnati OH 45221 United States

ISBN: (纸本)1424403294

Multiple beam antennas can initiate several data communications concurrently by forming spatially separable beams. However, their concurrent packet reception (CPR) capability is largely governed by the underlying medium access control (MAC) protocol. In this paper, we present an analytical framework to calculate CPR upper bounds of multiple beam antennas using on-demand MAC protocols. The model can be used for adaptively changing transmission probability of the nodes so as to achieve optimal performance. We consider both transmitter-initiated and receiver initiated medium access protocols with uniform and random distribution of nodes. Using the developed model, we compute CPR capability of IEEE 802.11 DCF and ESIF based mechanisms for multiple beam antennas. We verify our model using simulations. © 2006 IEEE.

关键词： Medium access control

来源：评论

学校读者我要写书评

暂无评论

Lifetime Enhancement of Wireless Sensor Networks by Differentiable Node Density Deployment

Lifetime Enhancement of Wireless Sensor Networks by Differen...

引用

IEEE Internatonal Conference on mobile Adhoc and Sensor Systems (MASS)

作者： Demin Wang Yi Cheng Yun Wang Dharma P. Agrawal OBR Center for Distributed and Mobile Computing Department of ECECS University of Cincinnati USA

A wireless sensor network (WSN) is composed of wireless sensors using batteries with energy constraints, which limits the network lifetime. How to maximize the network lifetime is an important issue in the design of WSNs. We establish a relationship between node density and network lifetime in a periodically data delivery scenario of WSNs with sensors transmitting data to the sink node periodically. Based on our analysis, we propose a sensor node density deployment method that could implement a differential node density in WSNs so that the lifetime of the network could be maximized. Both theoretic analysis and simulation results show that our method outperforms the uniform node distribution method in terms of the network lifetime

关键词： Wireless sensor networks Telecommunication traffic Relays Batteries Traffic control Energy consumption mobile computing Computer networks distributed computing Analytical models

来源：评论

学校读者我要写书评

暂无评论

Localization Algorithm using Expected Hop Progress in Wireless Sensor Networks

Localization Algorithm using Expected Hop Progress in Wirele...

引用

IEEE Internatonal Conference on mobile Adhoc and Sensor Systems (MASS)

作者： Yun Wang Xiaodong Wang Demin Wang Dharma P. Agrawal OBR Center of Distributed and Mobile Computing Department of ECECS University of Cincinnati USA

In this paper, we propose a novel localization algorithm using expected hop progress (LAEP) to predict the positions of sensor nodes in WSNs. Our algorithm is based on a hop progress analytical model for a given network topology. By deriving relationship between node connectivity and expected-hop progress from the model, the distance between any two nodes can be accurately computed. As the distance estimation is a key issue in positioning system of WSNs, our expected-hop progress based localization algorithm also achieves reasonable performance in anchor-based WSNs with very few anchors. In addition, we considered the impact of deterministic anchor placement on the algorithm performance when the sensors are random deployed. Both grid and triangular placement of anchor nodes have been examined in this paper. Simulation results are seen to be in good agreement with the theoretical analysis and substantiate the validity of our proposed scheme LAEP

关键词： Wireless sensor networks Analytical models Network topology Sensor phenomena and characterization Algorithm design and analysis mobile computing Computer networks distributed computing Monitoring Surveillance

来源：评论

学校读者我要写书评

暂无评论

Wireless Sensor based Dynamic Channel Selection in Cellular Communication by Cognitive Radio Approach

Wireless Sensor based Dynamic Channel Selection in Cellular ...

引用

International Conference on Cognitive Radio Oriented Wireless Networks and Communications

作者： Torsha Banerjee Chittabrata Ghosh Dharma P. Agrawal OBR Center for Distributed and Mobile Computing University of Cincinnati Cincinnati OH USA

ISBN: (纸本)1424413804

In a cellular communication scenario, wireless sensors can be deployed to sense the interference power of the frequency band. In an ideal channel, interference temperature (IT) which is directly proportional to the interference power can be assumed to vary spatially with the frequency of the sub channel. We propose a scheme for approximating ITs over an extended C-band (licensed and unused television band) by fitting sub channel frequencies and corresponding ITs to a regression model. Using this model, IT of a random sub channel can be calculated by the base station (BS) for further analysis of the channel interference. Our proposed model based on readings reported by sensors helps in dynamic channel selection (S-DCS) in extended C-band for assignment to unlicensed secondary users. S-DCS maximizes channel utilization and proves to be economic from energy consumption point of view. It also exhibits substantial amount of accuracy with error bound within 6.8%. Again, users are assigned empty sub channels without actually probing them, incurring minimum delay in the process. Overall channel allocation efficiency is also maximized along with fairness to individual users

关键词： Wireless sensor networks Cognitive radio Interference Frequency Wireless communication Temperature sensors TV Base stations Power generation economics Energy consumption

来源：评论

学校读者我要写书评

暂无评论

On-demand reliable medium access in sensor networks

On-demand reliable medium access in sensor networks

引用

IEEE International Symposium on World of Wireless mobile and Multimedia Networks (WoWMoM)

作者： R. Biswas V. Jain C. Ghosh D.P. Agrawal OBR Center for Distributed and Mobile Computing Department of ECECS University of Cincinnati USA

关键词： Media Access Protocol Wireless sensor networks Access protocols Fault tolerant systems Robustness Wireless communication Wireless application protocol Telecommunication network reliability Delay Scalability

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：