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针对异步MANETs网络提出了一种新的有效支持实时业务的接入协议———分布式异步PRMA。该协议在不依赖于中心控制器及全网的时钟同步的前提下提供资源预留机制,实现了话音业务的传输并保证了其时延要求。 相似文献
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Ren‐Hung Hwang Chiung‐Ying Wang Chi‐Jen Wu Guan‐Nan Chen 《International Journal of Communication Systems》2013,26(1):34-55
Following recent advances in the performance of ad hoc networks, the limited life of batteries in mobile devices poses a bottleneck in their development. Consequently, how to minimize power consumption in the Medium Access Control (MAC) layer of ad hoc networks is an essential issue. The power‐saving mode (PSM) of IEEE 802.11 involves the Timing Synchronization Function to reduce power consumption for single‐hop mobile ad hoc networks (MANETs). However, the IEEE 802.11 PSM is known to result in unnecessary energy consumption as well as the problems of overheating and back‐off time delay. Hence, this study presents an efficient power‐saving MAC protocol, called p‐MANET, based on a Multi‐hop Time Synchronization Protocol, which involves a hibernation mechanism, a beacon inhibition mechanism, and a low‐latency next‐hop selection mechanism for general‐purpose multi‐hop MANETs. The main purposes of the p‐MANET protocol are to reduce significantly the power consumption and the transmission latency. In the hibernation mechanism, each p‐MANET node needs only to wake up during one out of every N beacon interval, where N is the number of beacon intervals in a cycle. Thus, efficient power consumption is achieved. Furthermore, a beacon inhibition mechanism is proposed to prevent the beacon storm problem that is caused by synchronization and neighbor discovery messages. Finally, the low‐latency next‐hop selection mechanism is designed to yield low transmission latency. Each p‐MANET node is aware of the active beacon intervals of its neighbors by using a hash function, such that it can easily forward packets to a neighbor in active mode or with the least remaining time to wake up. As a consequence, upper‐layer routing protocols can cooperate with p‐MANET to select the next‐hop neighbor with the best forwarding delay. To verify the proposed design and demonstrate the favorable performance of the proposed p‐MANET, we present the theoretical analysis related to p‐MANET and also perform experimental simulations. The numerical results show that p‐MANET reduces power consumption and routing latency and performs well in extending lifetime with a small neighbor discovery time. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Hännikäinen Marko Lavikko Tommi Kukkala Petri Hämäläinen Timo D. 《Telecommunication Systems》2003,23(3-4):297-333
Quality of Service (QoS) support has generally been lacking from WPAN and WLAN technologies, which has motivated the research
of TUTWLAN. Design objectives have been relatively simple network architecture and capability to support real time services
ranging from sensor data to multimedia streaming. The main TUTWLAN entities for QoS support are the Medium Access Control
(MAC) protocol called TUTMAC and TUTWLAN Access Point (AP). The channel access is based on dynamic reservation Time Division
Multiple Access (TDMA). TUTWLAN is shown to be suitable for wireless home and office applications. It provides flexibility,
interoperability and availability of services exceeding the recent QoS proposals that has been accounted at the standardisation
bodies for standard wireless technologies.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
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In this paper we introduce a novel MAC protocol that provides Quality of Service (QoS) support for multimedia traffic in UWB-based
wireless local area networks. The proposed protocol allocates transmission opportunities to QoS and best effort traffic using
a set of scheduling and resource control algorithms. The algorithms account for the UWB characteristics such as the co-existence
of multiple simultaneous transmissions as well as the possibility of dynamically assigning the nodes' transmission rate and
power. The simulation results show that the proposed protocol can provide QoS support while optimizing resource utilization.
Yuechun Chu received her B.Sc. degree in electrical engineering from Shanghai University, China, in 1996 and M.Sc. degree in electrical
engineering from University of Science and Technology of China in 1999. She is currently pursuing the Ph.D. degree in the
department of electrical and computer engineering at the University of Massachusetts Amherst. Her research interests include
MAC protocol design for UWB-based networks, wireless multimedia applications, and architectures and protocols for wireless
networks with QoS guarantees.
Aura Ganz is currently an Associate Professor and Director of the Multimedia Networks Laboratory at the ECE Department, University
of Massachusetts at Amherst. She has experience in topics related to multimedia wireless networks, optical networks and ubiquitous
computing. The research results are validated by a combination of analytical, simulation and prototyping tools. She has published
a book “Multimedia Wireless Networks: Technologies, Standards and QoS” (Prentice Hall) and authored over one hundred and fifty
peer reviewed publications. Dr. Ganz received her BSc, MSc and Ph.D degrees in Computer Science from the Technion in Israel. 相似文献
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这篇文章提出了能够有效支持QoS的IEEE802.11自适应调度器模型。和以往的支持QoS的调度器模型相比,这里根据在主控接入点(MAP:Master Access Point)和用户终端(UT:User Termination)的各自延时需求对满足不同的传输机制的分组流进行自适应调度。这种机制不仅完全兼容当前支持QoS的IEEE802.11MAC协议标准,而且能够有效减少由于实时传输带来的分组延时,增加满足不同信道负载和带宽要求的数据流的吞吐率。实时测试得到的数据基本验证了这个要求。 相似文献
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The growing popularity of multimedia applications and services needs to support several quality of service metrics such as high throughput, low energy, and jitter, which is a challenging task in mobile ad hoc networks. Because of limited bandwidth, energy constraints, dynamic topology, transmission errors, and fluctuating link stability, the links between adjacent nodes are often not reliable and may break because of node mobility. Link breakage initiates the process of rerouting either at the sender node (the node at which the link breaks) or at the source node. In either case, it leads to packet loss, delivery delays, and increased control overheads. Hence, to attain a minimum quality of service, routing protocols must address the dynamic network topology. Uncertain and varying movement of nodes necessitates stability of the links between such nodes. The objective of this paper is to propose 2 protocols, the first based on link stability and the other based on route stability. Link stability identifies a stable link from the available links to the next hop and determines a stable end‐to‐end route. The probability of successful transmission of periodic packets is used as a link stability metric to assess the stable path. Acknowledgment ‐free packets are used to check connectivity in the network. Increased probability of successful transmission implies that the selected link is sustained for longer duration and can deliver packets more reliably or, as a consequence, results in a stable link to deliver a better data rate. With a stable link, there is a reduced possibility of retransmissions, reduced end‐to‐end delay, reduced control overheads, and enhanced data delivery ratio. Selection of the most stable route for data transmission improves the performance. Experimental results from simulations performed on EXata/Cyber v2.0 simulator reveal that our proposed protocols are an improvement over the existing protocols in terms of packet delivery ratio, average end‐to‐end delay, and average route lifetime, even without route optimization with the minor increase in control packets. A case study of the application of proposed protocols is also presented. 相似文献
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A mobile ad hoc network (MANET) is a self‐organized and adaptive wireless network formed by dynamically gathering mobile nodes. Since the topology of the network is constantly changing, the issue of routing packets and energy conservation become challenging tasks. In this paper, we propose a cross‐layer design that jointly considers routing and topology control taking mobility and interference into account for MANETs. We called the proposed protocol as Mobility‐aware Routing and Interference‐aware Topology control (MRIT) protocol. The main objective of the proposed protocol is to increase the network lifetime, reduce energy consumption, and find stable end‐to‐end routes for MANETs. We evaluate the performance of the proposed protocol by comprehensively simulating a set of random MANET environments. The results show that the proposed protocol reduces energy consumption rate, end‐to‐end delay, interference while preserving throughput and network connectivity. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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CUI Bing-feng ZHANG Xu DING Wei Broadband Communication Networks Lab Beijing University of Posts Telecommunications Beijing P.R. China 《中国邮电高校学报(英文版)》2004,11(3)
1 Introduction AstheQoSrequirementofserviceclasseshaschangeddramaticallyduringthepastyears,thesingle classbesteffortarchitecturecurrentlyusedintheinternetcan tmeettheincreasingneedofdifferenttrafficswithdiffer entQoSrequirements .Asaresult ,themanagementandcontrolofTrafficEngineering (TE)becomesmoreimportantinhigh speednetworksforserviceproviders.AccordingtoInternetEngineeringTaskForce ,TEisanaspectofnetworkengineeringconcernedwiththeissueofnetworkperformanceoptimization[1] .Thenewlye … 相似文献
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为有效减小Ad Hoc网络实时业务节点的信道接入时延,提升对多媒体业务的服务质量(QoS)保障,在研究时隙分配类多址协议的基础上,设计了一种新的基于时隙重构的分组预约协议。新协议时隙结构简单,具有较好的冲突化解能力,通过对空闲数据时隙的重构利用以及层级式的接入控制,取得了较好的时延保障性能。 相似文献
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EPON中保证QoS的动态带宽分配算法 总被引:3,自引:3,他引:0
作为一种新技术,EPON系统采取在下行信道使用广播方式而在上行信道使用时分多址(TDMA)方式,为用户提供共享传输介质的接入方式,因此就需要一种接入控制机制来为用户分配带宽。为了使EPON系统更好地支持QoS并且进一步提高带宽利用率,提出了一种新的固定周期轮询动态带宽分配算法,针对不同时延特性业务采用不同的授权分配算法。算法包括两部分:OLT时ONU的调度以及ONU内部不同优先级的队列之间的调度。最后讨论了包时延、系统吞吐量等仿真结果和性能分析。 相似文献
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基于QoS的动态网格资源分配策略研究 总被引:3,自引:0,他引:3
网格资源节点的动态性、网格资源的分布性和异构性,决定了基于QoS保证来满足用户的要求,如何在竞争资源的应用之间合理分配资源,使得在满足用户QoS要求的基础上资源的利用率最高成为一个急需解决的问题.针对网格资源的特性介绍了一种基于QoS的动态网格资源分配策略,提出了基于网格的资源预留机制,提高了资源管理的可靠性和准确性.在此基础上,提出了选择性QoS调整机制.仿真试验表明该方法能有效地确保系统QoS,并获得近似最优的资源分配方案. 相似文献
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一种支持QoS片上网络路由器的设计与实现 总被引:1,自引:1,他引:0
设计了一种8端口的NoC路由器.采用简化的VOQ结构,使用双交叉开关,可连接4个IP核,开关调度具有动态、确定和公平的特点,能够提供QoS保证,并有效降低了报文排头阻塞和片上网络面积.Synopsys Design Compiler的综合结果表明,基于0.13μm工艺实现后,面积为0.62mm2,工作频率可达500MHz. 相似文献
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MANETs在军事通信中的应用 总被引:1,自引:0,他引:1
MANETs是目前通信技术领域的焦点之一,它具有极强的适应和生存能力,其应用前景十分广阔。首先介绍了MANETs的概念、结构和特点,阐述了MANETs在军事通信中的重要作用,并提出了一种应用阶段的过渡结构。最后指出了MANETs应用于军事通信中的关键技术和研究方向。 相似文献
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This paper describes the CDMAC, a new Medium Access Control (MAC)protocol for multimedia traffic in CDMA wireless networks. Theprotocol intends to extract the maximum capacity and flexibilityout of the CDMA scheme and at the same time guarantee the expectedQoS of different service types. CDMAC is able to maintain QoSrequirements thanks to the shaping, policing and trafficdifferentiation performed by the scheduler. Moreover, an iterativealgorithm, applied at the beginning of each frame, is used to findthe optimal power vector for all mobiles present in the system,which maximize the system capacity. The basic constraint of thecapacity maximization process is that the BER QoS of eachconnection should be fulfilled. Finally a distributedimplementation, feasible in a practical scenario, is presented. 相似文献
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We consider a time-slotted W-CDMA system for mobile stations which are connected to the wired internet. We first present an architecture for such a system that is based on a request-permission protocol incorporating power control for Best Effort transmissions on the uplink. The requesting mobiles are permitted to transmit in the next time slot with a specified power according to a schedule computed by the Base Station. To devise this scheduling method, we formulate a globally optimizing integer program that maximizes the total weighted sum of all best-effort transmissions in the entire system, keeping in view the diverse target Bit Error Rates for each one. This problem is analysed and decomposed into sub-problems that can be solved locally by each Base Station. We devise two fast heuristics to solve the Base Station's sub-problem, so that the new schedule for each successive slot can be re-computed by each Base Station in a practical time-frame. We show that one heuristic is good enough to produce optimal solutions to the sub-problem in special cases. The method is further enhanced to take account of bandwidth and delay guarantees for other connections. It is also modified to ensure fairness for best-effort code channels suffering from persistent location-dependent errors. Finally, we show that a very similar approach can be used by the Base Station for scheduling on the downlink also, leading to a unified approach to scheduling in both directions. The efficacy of the uplink method is briefly demonstrated by simulations comparing the two variants with each other, and demonstrating that one achieves a consistently higher throughput than the other. 相似文献