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11.
为了能有效防止ARP攻击,在分析了ARP攻击方式后,提出了一种防止ARP报文攻击的方法和系统.该方法可以简单地检测ARP攻击行为,并能对检测到的ARP攻击报文进行处理。 相似文献
12.
本文介绍了ad hoc网络可生存性面临的问题和挑战,特别强调了军事需求.其中从三个方面探讨了ad hoc网络的可生存性问题:可生存的网络连接、可生存的通信服务及可生存性技术,尤其是对可生存性技术进行了较全面的剖析. 相似文献
13.
Tarek S. El‐Bawab Anura P. Jayasumana 《International Journal of Communication Systems》2001,14(2):231-241
Robust wavelength division multiplexing (Robust‐WDM) is a proposal to realize cost‐effective WDM local area networks (LANs) which can get around the expensive need for laser wavelength stabilization. The type of these networks that relies on an access protocol with aperiodic reservations and lenient‐token‐passing based control channel (the AR/LTP protocol) is promising. We look at the deployment of the AR/LTP analytical model in designing this type of network. The model is used to predict the effect of component and network parameters on the waiting time characteristics of the network. An increase in node operation times (i.e. receiver response time, transmitter select time and reservation period) would result in increasing the average waiting time of a connection request, but the waiting time is more sensitive to the physical span of the network and its size. It is also observed that increasing the inter‐reservation threshold may result in little increase in waiting time up to some limit beyond which delay increases rapidly. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
14.
The IEEE 802.11e medium access control (MAC) layer protocol is an emerging standard to support quality of service (QoS) in
802.11 wireless networks. Some recent work shows that the 802.11e hybrid coordination function (HCF) can improve significantly
the QoS support in 802.11 networks. A simple HCF referenced scheduler has been proposed in the 802.11e which takes into account
the QoS requirements of flows and allocates time to stations on the basis of the mean sending rate. As we show in this paper,
this HCF referenced scheduling algorithm is only efficient and works well for flows with strict constant bit rate (CBR) characteristics.
However, a lot of real-time applications, such as videoconferencing, have some variations in their packet sizes, sending rates
or even have variable bit rate (VBR) characteristics. In this paper we propose FHCF, a simple and efficient scheduling algorithm
for 802.11e that aims to be fair for both CBR and VBR flows. FHCF uses queue length estimations to tune its time allocation
to mobile stations. We present analytical model evaluations and a set of simulations results, and provide performance comparisons
with the 802.11e HCF referenced scheduler. Our performance study indicates that FHCF provides good fairness while supporting
bandwidth and delay requirements for a large range of network loads.
Pierre Ansel received a multidisciplinary in-depth scientific training in different fields such as Pure and Applied Mathematics, Physics,
Mechanics, Computer Science and Economics from the Ecole Polytechnique, Palaiseau, France. Then, he joined the Ecole Nationale
Superieure des Telecommunications, Paris, France in 2005 where he went further into electronics, databases, computer network
security and high speed networks. He received a multidisciplinary master of sciences degree and an additional master of sciences
degree in telecommunications in 2005. He did a summer internship in 2003 in INRIA, Sophia Antipolis, France where he worked
on the Quality of Service in 802.11 networks at Planete Group, France. Then in 2004, he joined France Telecom R&D, Issy-les-Moulineaux,
France to work on Intranet Security issues. He designed a WiFi security supervision architecture based on WiFi Intrusion Detection
Sensors. He is currently a French civil servant and belongs to the French Telecommunications Corps.
Qiang Ni received the B.Eng., M.Sc. and Ph.D. degrees from Hua Zhong University of Science and Technology (HUST), Wuhan City, China
in 1993, 1996 and 1999 respectively. He is currently a faculty member in the Electronic and Computer Engineering Division,School
of Engineering and Design, Brunel University, West London, U.K. Between 2004 and 2005 he was a Senior Researcher at the Hamilton
Institute, National University of Ireland, Maynooth. From 1999 to 2001, he was a post-doctoral research fellow in the multimedia
and wireless communication laboratory, HUST, China. He visited and conducted research at the wireless and networking group
of Microsoft Research Asia Lab during the year of 2000. From Sept. 2001 until may 2004, he was a research staff member at
the Planète group of INRIA Sophia Antipolis France. Since 2002, he has been active as a voting member at the IEEE 802.11 wireless
LAN standard working group. His current research interests include communication protocol design and performance analysis
for wireless networks, cross-layer optimizations, vertical handover and mobility management in mobile wireless networks, and
adaptive multimedia transmission over hybrid wired/wireless networks. He has authored /co-authored over 40 international journal/conference
papers, book chapters, and standard drafts in this field. He is a member of IEEE. E-mail: Qiang.Ni@ieee.org
Thierry Turletti received the M.S. (1990) and the Ph.D. (1995) degrees in computer science both from the University of Nice – Sophia Antipolis,
France. He has done his PhD studies in the RODEO group at INRIA Sophia Antipolis. During the year 1995–96, he was a postdoctoral
fellow in the Telemedia, Networks and Systems group at LCS, MIT. He is currently a research scientist at the Planete group
at INRIA Sophia Antipolis. His research interests include multimedia applications, congestion control and wireless networking.
Dr. Turletti currently serves on the Editorial Board of Wireless Communications and Mobile Computing. 相似文献
15.
The max-min fair scheduling problem in wireless ad-hoc networks is a non-convex optimization problem. A general framework
is presented for this optimization problem and analyzed to obtain a dual problem, which involves solving a series of optimization
sub-problems. In the limit of infinite bandwidth (
), the scheduling solution reduces to simultaneous transmission (spread spectrum) on all links (Negi and Rajeswaran, INFOCOM
'04 (March 2004)). This motivates the analysis of the scheduling problem in the Ultra Wide Band (UWB) regime (
, but finite), a model for certain practical radios. A quadratic (in 1/W) lower bound to the single link capacity function is developed, which simplifies the dual sub-problem to a quadratic optimization
(Negi and Rajeswaran, GLOBECOM '04, (Dec. 2004)). The solution to this sub-problem is then obtained under both total power and power spectral density constraints. This
solution is utilized to iteratively construct the schedule (sub-band sizes) and power allocation, thus optimally solving the
UWB max-min fair scheduling problem, to within any desired precision. Simulations on medium sized networks demonstrate the
excellent performance of this scheme. A cellular architecture (not necessarily UWB) may also be considered in this framework.
It is proved that Frequency Division Multiple Access is the optimal scheduling for a multi-band cellular architecture.
This work was supported in part by the National Science Foundation under Career award 0347455.
Arjunan Rajeswaran received his Masters degree in Electrical and Computer Engineering from Carnegie Mellon University in 2003. Since August
2003, he has been pursuing his doctoral research at Carnegie Mellon. His reserach interests lie in the area of wireless networks.
His focus is in the application of information and communication theoretic tools towards wireless network design. Several
IEEE publications reflect his curent research on Medium Access Control design and performance. Arjunan received the best student
paper award at IEEE/ACM Broadnets 2004.
Gyouhwan Kim received his B.S. and M.S. degree in Electronic Engineering from Sogang University in Korea, in 1994 and 1996, respectively.
Since 1996, he has been working in the CDMA cellular system development team in Samsung Electronics. Currently, he is also
working toward the Ph.D degree in the Department of Electrical and Computer Engineering at Carnegie Mellon University. His
main research interests are in wireless networks and communication theory.
Rohit Negi received the B.Tech. degree in Electrical Engineering from the Indian Institute of Technology, Bombay, India in 1995. He
received the M.S. and Ph.D. degrees from Stanford University, CA, USA, in 1996 and 2000 respectively, both in Electrical Engineering.
He has received the President of India Gold medal in 1995. Since 2000, he has been with the Electrical and Computer Engineering
department at Carnegie Mellon University, Pittsburgh, PA, USA, where he is an Assistant Professor. His research interests
include signal processing, coding for communications systems, information theory, networking, cross-layer optimization and
sensor networks. 相似文献
16.
Mobile computing is the way of the future, as evident by such initiatives as Bluetooth, Iceberg and HomeRF. However, for mobile computing to be successful, an obvious layer, the MAC layer, must be efficient in channel access and reservation. Therefore, in-depth understanding is needed of the wireless MAC layer if wireless computing is to takeoff. Many random access wireless MAC protocols have been proposed and even standardized. However, there has yet been an attempt to understand why certain designs are used and what makes certain protocols better than others. In this paper, we survey several popular, contemporary, wireless, random access MAC protocols and determine the effects behind the design choices of these protocols. 相似文献
17.
18.
针对现有太赫兹无线个域网定向MAC协议存在的波束训练开销和入网时延偏大以及Beacon, S-CAP时段时隙利用不足问题,该文提出一种自适应的定向MAC协议——AD-MAC,自适应地在静态场景下采用全网协同波束训练,在动态场景下节点基于历史信息快速回复波束训练帧,同时使用反向监听策略减小同扇区节点的帧碰撞概率,并且通过时隙复用在Beacon和S-CAP时段并行发送控制帧和数据帧。理论分析表明了AD-MAC协议的有效性,仿真结果显示:相较于ENLBT-MAC等典型协议,AD-MAC在静态场景下的波束训练开销和节点平均入网时延分别降低了约21.84%和22.70%,在动态场景下上述二指标则分别减小了约18.7%和13.07%。
相似文献19.
20.
1 Introduction Recently, the high rate short range wireless personal area network (WPAN) is considered. When the inverse of the sampling rate is significantly shorter than the total delay spread, as is the case for most UWB communication systems, OFDM systems are more attractive than a single-carrier system. The multi-band OFDM physical layer proposal has been adopt by IEEE 802.15.3a Task Group[1]。 Combing STC and OFDM have the properties to achieve high data rate and mitigate int… 相似文献