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1.
Mobile multimedia applications have recently generated much interest in mobile ad hoc networks (MANETs) supporting quality-of-service (QoS) communications. Multiple non-interfering channels are available in 802.11 and 802.15 based wireless networks. Capacity of such channels can be combined to achieve higher QoS performance than for single channel networks. The capacity of MANETs can be substantially increased by equipping each network node with multiple interfaces that can operate on multiple non-overlapping channels. However, new scheduling, channel assignment, and routing protocols are required to utilize the increased bandwidth in multichannel MANETs. In this paper, we propose an on-demand routing protocol M-QoS-AODV in multichannel MANETs that incorporates a distributed channel assignment scheme and routing discovery process to support multimedia communication and to satisfy QoS bandwidth requirement. The proposed channel assignment scheme can efficiently express the channel usage and interference information within a certain range, which reduces interference and enhances channel reuse rate. This cross-layer design approach can significantly improve the performance of multichannel MANETs over existing routing algorithms. Simulation results show that the proposed M-QoS-AODV protocol can effectively increase throughput and reduce delay, as compared to AODV and M-AODV-R protocols.  相似文献   

2.
Mobile Ad hoc NETworks (MANETs) are an important part of wireless communications and the increasing use of mobile devices is confirming that. MANETs can be of great value in Emergency Response situations where communication between mobile deployed units is critical and wired or wireless infrastructures may not be present or functional. In emergency scenarios, multimedia communication is very important for decision making and situation assessment. This requires up‐to‐date (on‐line) information feed on the situation, including voice and video from the affected zone. However, MANETs do not seem to efficiently support multimedia applications, and this is quite evident in video transmission. One way to remedy this is to use more (wireless) interfaces per mobile node and consequently more communication channels. In this work, we perform an analytical study on the use of multiple interfaces and multiple channels (MIMC) in video transmission with respect to the requirements of Emergency Response Ad hoc Networks. More specifically, we examine and present the impact of using MIMC on MANETs during video transmission applications, we evaluate the performance of three basic routing protocols in MANETs, and we propose a channel selection mechanism in MANET nodes with MIMC for enhanced video transmission. In addition, we evaluate video transmission streams with rate adaptation and present comparative results. The proposed mechanism is evaluated using the ns‐2 network simulator and the simulations are performed for a variety of topologies. Simulation results show that the different routing protocols respond differently when MIMC is introduced. The Ad hoc On‐Demand Multipath Distance Vector and (especially) the Ad hoc On‐Demand Distance Vector routing protocols benefit significantly, while the Destination Sequenced Distance Vector shows fewer improvements. The proposed mechanism is shown to be beneficial for transmitting video streams and enhances the network's ability to accommodate more streams and reduce packet delay. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

3.
Adhoc是一组无线移动主机组成的一个无需基础设施或集中管理设备的临时网络。网络拓扑易变、带宽、能源有限是其主要特点。文章主要介绍Adhoc网络和组网关键技术——路由协议,并对现在具有代表性的协议性能进行了比较分析,指出了下一步的研究方向。  相似文献   

4.
Mobile ad hoc networks (MANETs) are characterized by multiple entities, a frequently changing network topology and the need for efficient dynamic routing protocols. In MANETs, nodes are usually powered by batteries. Power control is tightly coupled with both the physical and medium access layers (MACs). However, if we increase the transmission power, at the same time we increase the interference to other nodes which diminish the transport capacity of wireless systems. Thus, the routing protocols based on hop count metric suffer from performance degradation when they operate over MANET. Routing in ad hoc wireless networks is not only a problem of finding a route with shortest length, but it is also a problem of finding a stable and good quality communication route in order to avoid any unnecessary packet loss. Cross-layer design of ad hoc wireless networks has been receiving increasing attention recently. Part of these researches suggests that routing should take into account physical layer characteristics. The goal of this paper is to improve the routing reliability in MANET and to reduce power consumption through cross-layer approach among physical, MAC and network layers. The proposed cross-layer approach is based on signal to interference plus noise ratio (SINR) and received signal strength indication (RSSI) coming from the physical layer. This solution performs in one hand the ad hoc on-demand distance vector routing protocol by choosing reliable routes with less interferences using SINR metric and in another hand; it permits to reduce the power transmission when sending the data packets by using RSSI metric.  相似文献   

5.
Power-aware routing protocols in ad hoc wireless networks   总被引:5,自引:0,他引:5  
An ad hoc wireless network has no fixed networking infrastructure. It consists of multiple, possibly mobile, nodes that maintain network connectivity through wireless communications. Such a network has practical applications in areas where it may not be economically practical or physically possible to provide a conventional networking infrastructure. The nodes in an ad hoc wireless network are typically powered by batteries with a limited energy supply. One of the most important and challenging issues in ad hoc wireless networks is how to conserve energy, maximizing the lifetime of its nodes and thus of the network itself. Since routing is an essential function in these networks, developing power-aware routing protocols for ad hoc wireless networks has been an intensive research area in recent years. As a result, many power-aware routing protocols have been proposed from a variety of perspectives. This article surveys the current state of power-aware routing protocols in ad hoc wireless networks.  相似文献   

6.
VANETs路由协议的研究进展   总被引:1,自引:0,他引:1       下载免费PDF全文
于海宁  张宏莉 《电子学报》2011,39(12):2868-2879
车辆自组织网络是传统自组织网络派生出的一个分支,其与应用场景高度相关.传统路由协议不能有效的适用于车辆自组织网络,因此,针对车辆自组织网络提出了许多新的路由协议.首先在总结车辆自组织网络的特性后,分别介绍了单播路由、广播路由和地域性多播路由的概念,然后着重分析和总结了近年来具有代表性的路由协议的核心路由机制及其优缺点,...  相似文献   

7.
Lee  S.-J. Gerla  M. Toh  C.-K. 《IEEE network》1999,13(4):48-54
Bandwidth and power constraints are the main concerns in current wireless networks because multihop ad hoc mobile wireless networks rely on each node in the network to act as a router and packet forwarder. This dependency places bandwidth, power, and computation demands on mobile hosts which must be taken into account when choosing the best routing protocol. In previous years, protocols that build routes based on demand have been proposed. The major goal of on-demand routing protocols is to minimize control traffic overhead. We perform a simulation and performance study on some routing protocols for ad hoc networks. The distributed Bellman-Ford (1957, 1962), a traditional table-driven routing algorithm, is simulated to evaluate its performance in multihop wireless network. In addition, two on-demand routing protocols (dynamic source routing and associativity-based routing) with distinctive route selection algorithms are simulated in a common environment to quantitatively measure and contrast their performance. The final selection of an appropriate protocol will depend on a variety of factors, which are discussed in this article  相似文献   

8.
Recently, wireless networks have become one of the major development trends in computer network technology. Because there is no more need of the wired transmission medium, applications have thus diversified. One such growing field of wireless networks is the mobile ad‐hoc network (MANET). A MANET consists of mobile hosts (such as portable laptops, vehicles, etc.), and no fixed infrastructure is required. MANETs provide ease of self‐configuration and can extend coverage at a low cost. Numerous applications have therefore been proposed under this network environment for daily life use. Because MANETs nodes are capable of moving, MANET network topology changes frequently. Thus, the traditional routing protocols fail to fit such an environment. In this paper, we propose an efficient routing protocol for MANETs, which integrates the mathematical model of profit optimization (the Kelly formula) from the field of economics to cope with the routing problem caused by node mobility. Some numerical simulations have been conducted to evaluate the performance of the proposed method using the network simulator NS‐2. The results show that our proposed method outperforms conventional routing protocols in packet delivery ratio comparisons; and the average end‐to‐end delays are within a tolerable range. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

9.
A growing need to have ubiquitous connectivity has motivated our research to provide continuous connection between various wireless platforms such as cellular networks, wireless local area networks (WLANs), and mobile ad hoc networks (MANETs). In this paper, we consider integration at the routing layer and propose two adaptable routing protocols (IRP‐RD and IRP‐PD) that exploit topology information stored at the fixed network components (cellular base stations and WLAN access points) for the route discovery and maintenance processes. Our proposed protocols can provide connectivity to the cellular network and/or WLAN hotspots through multihop routing, while differ in the gateway discovery approach used. In IRP‐RD, multihop routes to gateways to the cellular network or WLAN hot spots are discovered on demand, while in IRP‐PD out of coverage users proactively maintain routes to the gateways. Furthermore, proposed protocols can be used in any heterogeneous scenario, combining a cellular network and WLANs operating in infrastructure or ad hoc (MANET) mode. We provide simulation results that demonstrate the effectiveness of the proposed integrated routing protocols and show the advantages and drawbacks of each gateway discovery approach in different heterogeneous scenarios. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

10.
Security for ad hoc network environments has received a lot of attention as of today. Previous work has mainly been focussing on secure routing, fairness issues, and malicious node detection. However, the issue of introducing and conserving trust relationships has received considerably less attention. In this article, we present a scalable method for the use of public key certificates and their revocation in mobile ad hoc networks (MANETs). With the LKN-ad hoc security framework (LKN-ASF) a certificate management protocol has been introduced, bringing PKI technology to MANETs. In addition a performance analysis of two different revocation approaches for MANETs will be presented.  相似文献   

11.
To efficiently support tetherless applications in ad hoc wireless mobile computing networks, a judicious ad hoc routing protocol is needed. Much research has been done on designing ad hoc routing protocols and some well-known protocols are also being implemented in practical situations. However; one major imperfection in existing protocols is that the time-varying nature of the wireless channels among the mobile-terminals is ignored; let alone exploited. This could be a severe design drawback because the varying channel quality can lead to very poor overall route quality in turn, resulting in low data throughput. Indeed, better performance could be achieved if a routing protocol dynamically changes the routes according to the channel conditions. In this paper, we first propose two channel adaptive routing protocols which work by using an adaptive channel coding and modulation scheme that allows a mobile terminal to dynamically adjust the data throughput via changing the amount of error protection incorporated. We then present a qualitative and quantitative comparison of the two classes of ad hoc routing protocols. Extensive simulation results indicate that channel adaptive ad hoc routing protocols are more efficient in that shorter delays and higher rates are achieved, at the expense of a higher overhead in route set-up and maintenance.  相似文献   

12.
Mobile ad hoc networks (MANETs) are of much interest to both the research community and the military because of the potential to establish a communication network in any situation that involves emergencies. Examples are search‐and‐rescue operations, military deployment in hostile environments, and several types of police operations. One critical open issue is how to route messages considering the characteristics of these networks. The nodes act as routers in an environment without a fixed infrastructure, the nodes are mobile, the wireless medium has its own limitations compared to wired networks, and existing routing protocols cannot be employed, at least without modifications. Over the last few years, a number of routing protocols have been proposed and enhanced to address the issue of routing in MANETs. It is not clear how those different protocols perform under different environments. One protocol may be the best in one network configuration but the worst in another. This article provides an analysis and performance evaluation of those protocols that may be suitable for military communications. The evaluation is conducted in two phases. In the first phase, we compare the protocols based on qualitative metrics to locate those that may fit our evaluation criteria. In the second phase, we evaluate the selected protocols from the first phase based on quantitative metrics in a mobility scenario that reflects tactical military movements. The results disclose that there is no routing protocol in the current stage without modifications that can provide efficient routing to any size of network, regardless of the number of nodes and the network load and mobility. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

13.
In this paper, we present a new quality of service (QoS) routing protocol for mobile ad hoc networks (MANETs). Most of the existing routing protocols assume homogeneous nodes in MANETs, i.e., all nodes have the same communication capabilities and characteristics. However, in many ad hoc networks, nodes are not the same. Some nodes have longer transmission range, larger transmission bandwidth, and are more reliable and robust than other nodes. We take advantage of the non-homogeneous property to design more efficient QoS routing protocol. And node location information is used to aid routing. We also develop a new algorithm to calculate end-to-end bandwidth for a given path. Our QoS routing protocol contains end-to-end bandwidth calculation and bandwidth reservation. QoS route is discovered and setup only when it is needed. Extensive simulation studies demonstrate the good performance of the QoS routing protocol.  相似文献   

14.
Ad Hoe网中节点的任意运动,导致了大量的重路由操作,从而降低了网络性能。而基于预测的路由协议能够有效地减少网络拓扑结构的变化对于路由操作的影响。文章主要讨论了Ad Hoc网的特点以及目前已经提出的几种节点运动预测方案,同时对基于预测的路由协议进行研究。  相似文献   

15.
Recent research efforts in mobile ad hoc networks have concentrated on examining the behaviour of TCP Reno over various ad hoc routing protocols and have suggested a number of extensions to improve its performance. TCP Vegas, which takes a proactive approach to congestion avoidance, has not so far been examined as a viable alternative to TCP Reno in wireless environments and no effort has been made to analyse its performance over routing protocols for MANETs. This paper evaluates using extensive simulation experiments the performance behaviour of TCP Vegas over a proactive (destination sequenced distance vector) and two reactive (dynamic source routing and ad hoc on demand distance vector) routing protocols and compares it against that of TCP Reno. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

16.
A new cross-layer routing protocol, named Dynamic Packet Guidance (DPG), is introduced for Mobile Ad hoc Networks (MANETs). Simulation results show that DPG is quite useful for usage in dense networks of mobile nodes, with medium-to-high speeds, and low-to-medium load. In these scenarios, DPG provides a superior performance compared to several well-known ad hoc routing protocols. The low end-to-end delay and smaller overhead that DPG achieves in such scenarios positively impacts the scalability of MANETs and reduces the energy requirements of nodes in such networks. DPG also shows immunity to failing nodes, as it operates consistently almost independently of failing nodes up to a certain ratio.  相似文献   

17.
In this article, a comprehensive survey of the medium access control (MAC) approaches for wireless mobile ad hoc networks is presented. The complexity in MAC design for wireless ad hoc networks arises due to node mobility, radio link vulnerability and the lack of central coordination. A series of studies on MAC design has been conducted in the literature to improve medium access performance in different aspects as identified by the different performance metrics. Tradeoffs among the different performance metrics (such as between throughput and fairness) dictate the design of a suitable MAC protocol. We compare the different proposed MAC approaches, identify their problems and discuss the possible remedies. The interactions among the MAC and the higher layer protocols such as routing and transport layer protocols are discussed and some interesting research issues are also identified. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

18.
One of the infrastructure-free networks is mobile ad hoc networks (MANETs) that are built with limited battery life using wireless mobile devices. This restricted battery capability in MANETs creates the necessity of considering the energy-awareness constraint in designing them. As routing protocols, the major aim of MANETs is to create the energy awareness in the network; it improves the network's lifetime through effectively utilizing the available restricted energy. Moreover, it creates some limitations like the mobility constraint, wireless link's sensitivity to environmental impacts, and restricted transmission range and residual energy of nodes that causes rapid modifications in the network topology and frequent link failure. By taking those problems, this paper plans to develop a new multipath routing protocol, where the hybrid optimization algorithm with the integration of cuckoo search optimization (CSO) and butterfly optimization algorithm (BOA) is proposed and named sensory modality-based cuckoo search butterfly optimization (SM-CSBO) for determining the optimal path between the source and destination. The main goal is to select the path with better link quality and more stable links to guarantee reliable data transmission. The multi-objective function is considered with the factors regarding distance, normalized energy, packet delivery ratio, and control overhead to develop an effective routing protocol in MANET. The proposed model of SM-CSBO algorithm has superior than 5.8%, 30.4%, 36.7%, and 39.3%, correspondingly maximized than PSO, SFO, CSO, and SFO algorithms while considering the number of nodes as 150. The simulation outcomes proved that it enhances network performance when compared with the other traditional protocols.  相似文献   

19.
着重分析无线多跳移动网络中,不同路由算法对多媒体通信流自相似特性的影响.通过NS2仿真产生基于不同路由算法的通信流数据,运用V-T法和R/S图法分别分析其突发性参数.结果表明,基于表驱动的DSDV自相似参数最大,而分簇路由算法CBRP自相似参数最小,更有利于实时流媒体的传输.研究对提高无线网络路由协议的性能和多媒体服务的质量具有重要意义.  相似文献   

20.
There is a growing need to provide better service differentiation in mobile ad hoc networks; however, this is challenging. These networks are characterized as being multihop in nature where the wireless topology that interconnects mobile hosts/routers can change rapidly in unpredictable ways or remain relatively static over long periods of time. Power and bandwidth constrained, mobile ad hoc networks typically only support best effort communications where the transport protocol's “goodput” is often lower than the maximum radio transmission rate after encountering the effects of multiple access, fading, noise, and interference. We evaluate three routing protocols with INSIGNIA, an in-band signaling system that supports adaptive reservation-based services in mobile ad hoc networks. INSIGNIA represents a general-purpose approach to delivering quality of service in mobile ad hoc network supporting “operational transparency” between a number of IETF mobile ad hoc network routing protocols that include Ad Hoc On-Demand Distance Vector, Dynamic Source Routing, and the Temporally Ordered Routing Algorithm. We evaluate the performance gains delivered when using INSIGNIA with these MANET routing protocols in support of UDP and TCP traffic. The INSIGNIA ns-2 code used for the study reported in this article is available from the Web at comet.columbia.edu/insignia  相似文献   

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