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基于随机竞争和冲突解决的思想,本文为多跳移动Ad Hoc网络提出了一种分布式服务质量(QoS)保证的多址接入(QMA)协议.该协议中,节点在发送业务分组前利用预报突发进行竞争接入,节点根据业务分组时延情况和最早失效优先原则确定预报突发的长度,所发预报突发能持续到最后的节点优先获得接入.同时,具有实时业务的节点可以按照其优先级在更早的竞争微时隙中开始发送预报突发,而有非实时业务的节点只能在前面竞争微时隙空闲的情况下,才能在后面的微时隙开始发送预报突发,因此发送实时业务的节点可以比发送非实时业务的节点更优先接入信道,从而在移动Ad Hoc网络中实现了对多媒体业务的QoS保证.最后利用OPNET仿真评估了QMA协议的多址性能,并与IEEE 802.11e协议的性能做了比较,结果表明QMA协议可以提供较高的吞吐量和较低的实时业务时延. 相似文献
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本文提出了基于有效竞争接入、高效无冲突传输的多址接入协议—UPMA+ +.该协议采用了有效的冲突分解策略和及时重获信道资源的方法,克服了UPMA(根据用户数目妥善安排传输的多址接入)协议中的开销;通过自适应调整竞争接入周期长度和限制无冲突服务周期长度的方法,很好地解决了激活节点快速接入信道和传输节点尽快传输分组之间的矛盾,从而提高了协议的吞吐量.本文还应用排队论的方法对UPMA+ +协议的性能进行了理论分析,计算结果与仿真结果基本一致. 相似文献
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多跳结构分组无线网络的性能分析 总被引:5,自引:0,他引:5
本文提出了一种应用IEEE
802.11 MAC中RTS/CTS协议的多跳分组无线网络,分析了它的吞吐量,并与时隙ALOHA、CSMA多址接入协议下的网络性能作了比较.最小ID号的分群算法可以通过较少的控制信息快速得到顽健的分群网络结构,选用合适的MAC协议能充分有效地利用多信道.不过,两跳的分群结构使得在群内使用CSMA仍无法避免隐藏终端问题,IEEE
802.11 MAC协议中的RTS/CTS接入方式大大减小了隐藏间的分组碰撞时间,从而提高了网络性能. 相似文献
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本文首先介绍了QoS的概念模型,然后着重分析了QoS中RSCP(资源预留协议)在移动IP上存在的问题并提出了RSVP与移动IP结合的几种方案,在此基础上介绍了一种在移动IP上提供端到端的QoS机制。 相似文献
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本文提出了一种新的、支持数据/话音业务并传的多址接入协议——根据用户数目妥善安排分组传输的多址接入(User-dependent Perfect-scheduling Multiple Access——UPMA)协议,它根据实际需求对上、下行带宽资源实行动态分配.UPMA协议对不同的业务类型赋予不同的优先级,并用轮询方式妥善地安排节点的分组传输;同时,它采用独特的帧结构,使话音业务总是能够得到优先传输.本文还提出了一种高效的竞争接入算法,以保证激活的节点能够快速接入信道.最后,对UPMA协议的性能进行了仿真并与MPRMA协议的性能进行了比较,结果证明UPMA协议有更好的性能. 相似文献
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基于多信道预约可冲突避免的多址接入协议 总被引:3,自引:0,他引:3
本文为多跳分布多无线网络提出了一套灵活而有效的自适应获取冲突避免(AACA)的多址接入协议。在该协议中,各节点竞争公共信道,利用RTS/CTS对话形式来预约各业务信道,成功预约后的分组传输不会受到其他节点的干扰。它使用任意确定数目信道,以异步方式工作,并且使得各节点利用半双工无线电台就可以灵活、简便地实现资源预约。分析和比较结果说明,所提出的多信道预约协议可以有效地解决隐藏终端、暴露终端以及侵入终端的问题。 相似文献
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Using directional antennas in wireless mobile ad hoc networks can greatly improve the transmission range as well as the spatial
reuse. However, it will also cause some problems such as deafness problem and hidden terminal problem, which greatly impair
the network performance. This paper first proposes a MAC protocol called Selectively Directional MAC (SDMAC) that can effectively
address these problems and significantly improve the network throughput. Then two improvements on SDMAC are proposed. The
first one is to improve the network throughput by scheduling the packets in the queue (a scheme called Q-SDMAC), thus the
head-of-line (HOL) blocking problem can be addressed. The second one is to relax the assumption that each node knows the relative
directions of its neighboring nodes and use caches to buffer those relative directions (a scheme named Q-SDMAC using cache).
Extensive simulations show that: (1) SDMAC can achieve much better performance than the existing MAC protocols using directional
antennas; (2) The network throughput can be significantly improved by scheduling the packets in the queue; (3) Using caches
can still achieve high network throughput when nodes are moving; and (4) Network throughput decreases when directional antennas
have side lobe gain.
相似文献
Yuguang Fang (Corresponding author)Email: |
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In this paper, we investigate the issues of QoS multicast routing in wireless ad hoc networks. Due to limited bandwidth of a wireless node, a QoS multicast call could often be blocked if there does not exist a single multicast tree that has the requested bandwidth, even though there is enough bandwidth in the system to support the call. In this paper, we propose a new multicast routing scheme by using multiple paths or multiple trees to meet the bandwidth requirement of a call. Three multicast routing strategies are studied, SPT (shortest path tree) based multiple-paths (SPTM), least cost tree based multiple-paths (LCTM) and multiple least cost trees (MLCT). The final routing tree(s) can meet the user’s QoS requirements such that the delay from the source to any destination node shall not exceed the required bound and the aggregate bandwidth of the paths or trees shall meet the bandwidth requirement of the call. Extensive simulations have been conducted to evaluate the performance of our three multicast routing strategies. The simulation results show that the new scheme improves the call success ratio and makes a better use of network resources. 相似文献
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Satyabrata Chakrabarti Amitabh Mishra 《Wireless Communications and Mobile Computing》2004,4(2):129-153
Wireless mobile ad hoc networks consist of mobile nodes interconnected by wireless multi‐hop communication paths. Unlike conventional wireless networks, ad hoc networks have no fixed network infrastructure or administrative support. The topology of such networks changes dynamically as mobile nodes join or depart the network or radio links between nodes become unusable. Supporting appropriate quality of service for mobile ad hoc networks is a complex and difficult issue because of the dynamic nature of the network topology and generally imprecise network state information, and has become an intensely active area of research in the last few years. This paper 1 This article, except for some minor changes, is essentially the same as one that appears in 103 . The latter is a revised and updated version of 51 presents the basic concepts of quality of service support in ad hoc networks for unicast communication, reviews the major areas of current research and results, and addresses some new issues. The principal focus is on routing and security issues associated with quality of service support. The paper concludes with some observations on the open areas for further investigation. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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Quality of service (QoS) routing plays an important role in QoS provisioning for mobile ad hoc networks. This work studies the issue of route selection subject to QoS constraint(s). Our method searches for alternate routes with satisfied QoS requirement(s) to accommodate each communication request when the shortest path connecting the source–destination pair of the request is not qualified. In order to effectively reduce protocol overhead, a directed search mechanism is designed to limit the breadth of the searching scope, which aims at achieving a graceful tradeoff between the success probability in QoS route acquisition and communication overhead. Efficient hop‐by‐hop routing protocols are designed for route selection subject to delay and bandwidth constraint, respectively. Simulation results show that the designed protocols can achieve high performance in acquiring QoS paths and in efficient resource utilization with low control overhead. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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In order to allow truly spontaneous and infrastructureless networking, autoconfiguration algorithm is needed in the practical
usage of most mobile ad hoc networks (MANETs). This paper presents spanning-tree based autoconfiguration for mobile ad hoc
networks, a novel approach for the efficient distributed address autoconfiguration. With the help of the spanning tree, the
proposed scheme attempts to distribute address resources as balanced as possible at the first beginning. Since each node holds
a block of free addresses, a newly joining node can obtain a free address almost immediately. Subnet partitioning and merging
are well supported. Finally, analysis and simulation demonstrate that our algorithm outperforms the existing approaches in
terms of both communication overhead and configuration latency. 相似文献
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引入数字多波束技术可以使移动自组织网络的信道容量得到有效提升,然而,时间、频率、空间、用户、功率等多维度资源域的统一调度与跨层联合优化使得信道接入机制的分析与设计变得更加复杂。为此,结合多波束的特性,将波束宽度限制、收发限制、通道限制、功率限制等多种约束条件抽象图论问题,并建立分析模型。基于分析模型,进一步提出了MB-MAC(Multi-beam Medium Access Control)信道接入机制,结合物理层的预编码技术,建立定向链路的队列模型,度量用户的满意度(Quality of Experience,QoE),设计了适用于自组织网络中多用户并发并收的信道接入机制,兼顾了网络容量和用户满意度。仿真结果表明,MB-MAC机制能在保证各个用户满意度的情况下,有效提升网络吞吐率。 相似文献
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The mobile ad hoc network (MANET) has recently been recognized as an attractive network architecture for wireless communication. Reliable broadcast is an important operation in MANET (e.g., giving orders, searching routes, and notifying important signals). However, using a naive flooding to achieve reliable broadcasting may be very costly, causing a lot of contention, collision, and congestion, to which we refer as the broadcast storm problem. This paper proposes an efficient reliable broadcasting protocol by taking care of the potential broadcast storm problem that could occur in the medium-access level. Existing protocols are either unreliable, or reliable but based on a too costly approach. Our protocol differs from existing protocols by adopting a low-cost broadcast, which does not guarantee reliability, as a basic operation. The reliability is ensured by additional acknowledgement and handshaking. Simulation results do justify the efficiency of the proposed protocol. 相似文献
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Robust position-based routing for wireless ad hoc networks 总被引:1,自引:0,他引:1
We consider a wireless ad hoc network composed of a set of wireless nodes distributed in a two dimensional plane. Several routing protocols based on the positions of the mobile hosts have been proposed in the literature. A typical assumption in these protocols is that all wireless nodes have uniform transmission regions modeled by unit disk centered at each wireless node. However, all these protocols are likely to fail if the transmission ranges of the mobile hosts vary due to natural or man-made obstacles or weather conditions. These protocols may fail because either some connections that are used by routing protocols do not exist, which effectively results in disconnecting the network, or the use of some connections causes livelocks. In this paper, we describe a robust routing protocol that tolerates up to roughly 40% of variation in the transmission ranges of the mobile hosts. More precisely, our protocol guarantees message delivery in a connected ad hoc network whenever the ratio of the maximum transmission range to the minimum transmission range is at most . 相似文献
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Energy use is a crucial design concern in wireless ad hoc networks since wireless terminals are typically battery-operated.
The design objectives of energy-aware routing are two folds: Selecting energy-efficient paths and minimizing the protocol
overhead incurred for acquiring such paths. To achieve these goals simultaneously, we present the design of several on-demand
energy-aware routing protocols. The key idea behind our design is to adaptively select the subset of nodes that are required
to involve in a route-searching process in order to acquire a high residual-energy path and/or the degree to which nodes are
required to participate in the process of searching for a low-power path in networks wherein nodes have transmission power
adjusting capability. Analytical and simulation results are given to demonstrate the high performance of the designed protocols
in energy-efficient utilization as well as in reducing the protocol overhead incurred in acquiring energy-efficient routes.
Baoxian Zhang received his B.S., M.S., and Ph.D. degrees in Electrical Engineering from Northern Jiaotong University, Beijing, China in
1994, 1997, and 2000, respectively. From January 2001 to August 2002, he was working with Department of Electrical and Computer
Engineering at Queen’s University in Kingston as a postdoctoral fellow. He is currently a research scientist with the School
of Information Technology and Engineering (SITE) of University of Ottawa in Ottawa, Ontario, Canada. He has published over
40 refereed technical papers in international journals and conference proceedings. His research interests include routing
algorithm and protocol design, QoS management, wireless ad hoc and sensor networks, survivable optical networks, multicast
communications, and performance evaluation. He is a member of the IEEE.
Hussein Mouftah joined the School of Information Technology and Engineering (SITE) of the University of Ottawa in September 2002 as a Canada
Research Chair (Tier 1) Professor in Optical Networks. He has been with the Department of Electrical and Computer Engineering
at Queen’s University (1979-2002), where he was prior to his departure a Full Professor and the Department Associate Head.
He has three years of industrial experience mainly at Bell Northern Research of Ottawa, now Nortel Networks (1977-79). He
has spent three sabbatical years also at Nortel Networks (1986-87, 1993-94, and 2000-01), always conducting research in the
area of broadband packet switching networks, mobile wireless networks and quality of service over the optical Internet. He
served as Editor-in-Chief of the IEEE Communications Magazine (1995-97) and IEEE Communications Society Director of Magazines
(1998-99) and Chair of the Awards Committee (2002-2003). He is a Distinguished Speaker of the IEEE Communications Society
since 2000.
Dr. Mouftah is the author or coauthor of five books, 22 book chapters and more than 700 technical papers and 8 patents in
this area. He is the recipient of the 1989 Engineering Medal for Research and Development of the Association of Professional
Engineers of Ontario (PEO), and the Ontario Distinguished Researcher Award of the Ontario Innovation Trust. He is the joint
holder of the Best Paper Award for a paper presented at SPECTS’2002, and the Outstanding Paper Award for papers presented
at the IEEE HPSR’2002 and the IEEE ISMVL’1985. Also he is the joint holder of a Honorable Mention for the Frederick W. Ellersick
Price Paper Award for Best Paper in the IEEE Communications Magazine in 1993. He is the recipient of the IEEE Canada (Region
7) Outstanding Service Award (1995). Also he is the recipient of the 2004 IEEE Communications Society Edwin Howard Armstrong
Achievement Award, and the 2004 George S. Glinski Award for Excellence in Research of the Faculty of Engineering, University
of Ottawa. Dr. Mouftah is a Fellow of the IEEE (1990) and Fellow of the Canadian Academy of Engineering (2003). 相似文献
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Yunfeng Peng Riheng Jia Xing Gao Xiaoying Gan 《Wireless Communications and Mobile Computing》2016,16(15):2287-2297
With the prevalence of mobile devices, it is of much interest to study the properties of mobile ad hoc networks. In this paper, we extend the concept of diameter from static ad hoc network to mobile ad hoc network, which is the expected number of rounds for one node to transmit a message to all other nodes in the network, reflecting the worst end‐to‐end delay between any two node. Specifically, we investigate the diameter of identically and independently mobility model in cell‐partitioned network and random walk mobility model in two‐dimensional torus network, achieving the boundary , when (k=Ω(n)), and O(k log2k), respectively, where n is the number of nodes and k is the number of cells of network and especially under random walk mobility model . A comparison is made among the diameter of mobile ad hoc networks under identically and independently mobility model, random walk mobility model and static ad hoc network, showing that mobility dramatically decreases the diameter of the network and speed is an essential and decisive factor of diameter. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献