Ad Hoc与Internet互连的动态网关方案

移动Ad Hoe网络(MANET)是一种自治的、不需要固定基础设施的网络.将MANET与Internet连接可以扩展MANET的应用,实现资源共享,扩大网络的覆盖范围.文中提出一种具有三个层次的MANET与Internet互连的动态网关方案,把动态网关作为连接MANET和Internet的界面.最后文中通过仿真试验,动态网关方案使混合网络的性能得到了提高.     

移动自组织网络的研究与应用

移动自组织网络(mobile Ad hoc network,MANET)是一种没有固定通信基础设施的网络,由移动节点自组织、自管理、自维护,通过节点的互相协作、多跳转发实现节点间的通信.本文对MANET的概念、特点、体系结构作了简要介绍.分析了当前的主要研究内容和面临的挑战,展望了其广阔的应用前景.     

网络编码在MANET最小能量多播中的应用研究

网络编码理论是当代信息论的重要组成部分,移动特设网络(MANET)是由-组带有无线收发装置的移动终端组成的一个多跳临时性自治系统,利用网络编码理论解决MANET中最小能量多播问题是无线通信中新的研究热点之一.文中阐述了网络编码基本理论在无线通信中应用的技术原理,然后通过构建无线网络节点分层模型分析了基于网络编码的MANET最小能量求解过程,为解决该类型网络中能耗问题提供新的视角.     

基于车队行进场景的MANET移动模型研究

针对特定场景研究移动Ad Hoc网络(MANET)是当前研究的重点,而移动模型是研究MANET的基础,因此如何选择或建立更贴近实际应用场景的移动模型成为了研究MANET的关键环节。通过对现有典型移动模型的研究和分析,提出了一种模拟车队行进场景的移动模型,并利用NS2软件在此移动模型基础上对MANET性能进行仿真与分析,仿真结果表明,与传统的移动模型相比,该模型能更好地贴近车队行进场景。     

基于定位的移动Adhoc网络路由技术

路由协议是移动Ad hoc网络(MANET)研究的一个热点.传统的MANET的路由协议都是基于图形学建模的,只能获知各个节点之间的连通关系,而不能获知节点之间地理位置的关系.本文将要介绍基于定位的MANET路由协议,这些协议利用定位信息,从各方面改善MANET路由协议的性能.     

基于IEEE 802.11n的MANET网络移动终端的设计与实现

自组织网络和嵌入式系统都是当前的研究热点,本文结合这两方面,设计并实现了基于IEEE 802.11n Draft 2.0的移动自组织网络(MANET,Mobile Ad hocNetwork)的终端节点,并利用此移动终端搭建出MANET网络,最终在此网络上实现了稳定快速的数据、语音视频的通信.除了通过无线接入点(AP)实现作为因特网的无线接入子网,本文设计的移动终端由于采用最新技术,拥有更良好的性能,更有利于地震灾害、军事通信、移动会议等的临时通信网络的建立.移动终端作为一嵌入式系统,其硬件核心采用基于英特尔最新的Xscale架构的PXA270处理器,软件系统主要采用移植,二次开发开源软件(GNU/Linux2.6、AODV路由协议等)来实现.根据实验结果,论文还分析了MANET网络拓扑结构剧变导致网络性能下降的原因并提出解决方案.     

基于MANET的移动学习及其系统构建研究

移动自组网（MANET）是一种具有高度动态拓扑结构、节点任意移动的无线移动通信网络。针对MANET的特点及其应用,探讨了基于MANET的移动学习及其系统构建,并通过JisT／SWANS平台进行仿真实验,仿真结果证明MANET具有良好的通信性能。基于MANET的移动学习系统,能够实现随时随地、快速、有效的学习及资源共享,促进教育公平和教育资源效益的最大化。     

浅谈MANET网络攻击类型与网络安全

随着计算机网络技术的高速发展,互联网技术的应用越来越广泛.很快,由传统的防单机病毒,人们更加意识到网络安全的重要性.很多类型的攻击每天都在增加,保护计算机和网络安全是关键问题.MANET在计算机技术方面定义为移动自组网络的工作组,全称为Mobile Ad-hoc NETworks.本文描述了网络安全机密向量、网络安全完整性向量和网络安全可用性向量,并提出了MANET中的主要攻击类型.     

移动自组织网络关键技术

移动自组织网络(MANET)是一种不需要基础设施投入的自主无线通信网络,多个移动设备分布式协同工作,提供必要的网络通信功能,在传感器网络、紧急救援、军事等领域据具有广泛的潜在应用。为阐明MANET关键技术,首先介绍了MANET的应用场合,然后着重阐明了设计与开发过程中面临的路由,服务与资源发现,互联网接入,安全等关键问题,这对促进MANET研发具有重要意义。     

移动自组织网与有线网融合技术研究与展望

随着移动自组织网络(MANET)组网技术的不断成熟,MANET路由协议与传统Internet路由协议的融合已经成为网络互联的重要内容,成为影响组网效率的决定性因素.本文分别对移动自组织网络作为末端网和承载网的互联技术进行了研究,并在此基础上提出了基于无线栅格网络(wireless mesh networl,WMN)结构的未来移动互联技术的演进方案,对WMN的路由协议进行了有意义的探讨.     

Urban pedestrian mobility for mobile wireless network simulation

In order to perform precise evaluation of MANET applications in the real world, realistic mobility models are needed in wireless network simulation. In this paper, we propose a new method to create urban pedestrian flows (UPF) mobility scenarios, which reproduce the walking behavior of pedestrians in urban areas. From given densities of pedestrians observed at several points, our method derives a UPF mobility scenario that reproduces the walking behavior of pedestrians consistent with the observed densities, using linear programming techniques. We have developed a network simulator MobiREAL to design and evaluate MANET protocols and applications with this realistic mobility model. MobiREAL provides various functions and tools including a mobility model to describe the behavior of individual nodes, a GUI to assist with automatic generation of UPF mobility scenarios and a visualization tool. We have conducted some experiments using the MobiREAL simulator. Through the experiments, we have investigated the influence of node mobility on the performance of MANET protocols and have shown the usefulness of our method and the MobiREAL simulator.     

A Mobility-Prediction-Based Relay Deployment Framework for Conserving Power in MANETs

There has been a growing interest in designing mobile systems consisting of special relay nodes whose mobility can be controlled by the underlying network. In this paper, we consider the design of a heterogeneous mobile ad hoc network (MANET) consisting of two kinds of mobile nodes-traditional nodes with limited energy and a few controllable mobile relay nodes with relatively abundant energy resources. We propose a novel relay deployment framework that utilizes mobility prediction and works in tandem with the underlying MANET routing protocol to optimally define the movement of the relay nodes. We present two instances of the relay deployment problem, together with the solutions, to achieve different goals. Instance 1, termed Min-Total, aims to minimize the total energy consumed across all the traditional nodes during data transmission, while instance 2, termed Min-Max, aims to minimize the maximum energy consumed by a traditional node during data transmission. Our solutions also enable the prioritization of individual nodes in the network based on residual energy profiles and contextual significance. We perform an extensive simulation study to understand the trade-offs involved in deploying an increasing fraction of such relay nodes in the network. We also investigate the performance of the proposed framework under different mobility prediction schemes. Results indicate that even when the relay nodes constitute a small fraction of the total nodes in the network, the proposed framework results in significant energy savings. Further, we observed that while both the schemes have their potential advantages, the differences between the two optimization schemes are clearly highlighted in a sparse network.     

Using group mobility and multihomed mobile gateways to connect mobile ad hoc networks to the global IP Internet

Connecting multihop mobile ad hoc wireless networks (MANETs) to the Internet would enable MANET nodes to share wireless Internet access with mobile hosts that are one‐hop away from their foreign networks. The integration of MANETs and the global Internet, however, faces an obstacle due to their network architectural mismatches regarding their infrastructure, topology, and mobility management mechanisms. Solutions to the integration problem should introduce an intermediate facility with hybrid mechanism, enabling it to connect to both networks. The quality of the multihop wireless Internet access service provided to MANET nodes depends on the design quality of this facility in order for MANET nodes to enjoy their Internet connectivity anywhere and anytime without much disconnections. In this paper, we propose hierarchical architecture that uses group mobility and multihomed mobile gateways, and present and analyse different simulations results. A multihomed mobile gateway can simultaneously connect to multiple Mobile IP foreign agents, provided it is located within their overlapping coverage area. It runs updated versions of the destination‐sequenced distance vector (DSDV) and Mobile IP protocols, and is responsible for providing MANET nodes with wireless Internet access though they are multiple wireless hops away from the edge of the Internet. The rationale behind using multihoming is to increase reliability of the Internet access service and enhance performance of the integrated network. Copyright © 2006 John Wiley & Sons, Ltd.     

Ring Mesh Based Multicast Routing Scheme in MANET Using Bandwidth Delay Product

Quality of Service (QoS) support in Mobile Ad Hoc Networks (MANETs) for group communication necessitates design of reliable networks with multicast support mechanisms. Reliable network connectivity among MANET nodes require high quality links that have much less packet drops and reliable nodes considering node mobility and failures. Reliability of a network can be enhanced by designing an end-to-end network pipe that satisfies the required QoS in terms of in-flight packets from source to a destination as well as by using a path comprising of reliable nodes. In-flight packets may be computed by using bandwidth delay product (BDP) of a network pipe. To meet the QoS requirements of an application, BDP should be maintained stable irrespective of vibrant network conditions. In this paper, we propose a BDP based multicast routing scheme in MANET using reliable ring mesh backbone. The scheme operates in the following sequence. (1) Reliable node pairs are computed based on mobility, remaining battery power and differential signal strength. The node pairs also compute BDP between them. BDP of a reliability pair is assessed using available bandwidth and delay experienced by a packet between them. (2) Backbone ring mesh is constructed using reliable pair nodes and convex hull algorithm. Reliable ring mesh is constructed at an arbitrary distance from the centroid of the MANET area. (3) Multicast paths are found by discovering a path from source to each destination of the group with concatenated set of reliability pairs that satisfy the BDP requirement. (4) The ring mesh maintains high BDP on ring links and can recover in case of node mobility and failures. Results show that there is an improvement in terms of end-to-end delay, packet delivery ratio, control overhead, memory overhead and application rejection ratio as compared to the Enhanced On Demand Multicast Routing Protocol.     

一种基于中心代理的移动Ad—Hoc网络接入方法

本文针对已有接入方法所存在的缺点,提出一种以移动节点间相互竞争出现的中心节点作为移动代理,利用移动IP协议实现MANET接入Internet的新方法,并对中心代理节点的选取、MANET整体移动接入等问题进行了探讨。该方法具有开销小、接入灵活、不需对移动IP做大的改动等优点。     

The IMPORTANT framework for analyzing the Impact of Mobility on Performance Of RouTing protocols for Adhoc NeTworks

A Mobile Ad hoc Network (MANET) is a collection of wireless mobile nodes forming a temporary network without using any existing infrastructure. Since not many MANETs are currently deployed, research in this area is mostly simulation based. Random Waypoint is the commonly used mobility model in these simulations. Random Waypoint is a simple model that may be applicable to some scenarios. However, we believe that it is not sufficient to capture some important mobility characteristics of scenarios in which MANETs may be deployed. Our framework aims to evaluate the impact of different mobility models on the performance of MANET routing protocols. We propose various protocol independent metrics to capture interesting mobility characteristics, including spatial and temporal dependence and geographic restrictions. In addition, a rich set of parameterized mobility models is introduced including Random Waypoint, Group Mobility, Freeway and Manhattan models. Based on these models several ‘test-suite’ scenarios are chosen carefully to span the metric space. We demonstrate the utility of our test-suite by evaluating various MANET routing protocols, including DSR, AODV and DSDV. Our results show that the protocol performance may vary drastically across mobility models and performance rankings of protocols may vary with the mobility models used. This effect can be explained by the interaction of the mobility characteristics with the connectivity graph properties. Finally, we attempt to decompose the reactive routing protocols into mechanistic “building blocks” to gain a deeper insight into the performance variations across protocols in the face of mobility.     

面向群组移动的轻型位置服务研究

针对现实应用中大规模MANET网络节点呈现的群组移动特性,提出了面向群组移动的轻型位置服务协议GHLLS。G-HLLS协议将HLLS协议框架与分簇机制相结合,从而保证位置更新及请求机制适应群组移动特性。基于OPNET的仿真实验,从负载、服务成功率、存储开销多个方面对G-HLLS协议性能进行了分析,验证了G-HLLS协议在大规模群组移动网络中表现出的优越性能。     

Energy and delay efficient dynamic cluster formation using hybrid AGA with FACO in EAACK MANETs

MANET is a set of mobile nodes which works in a dynamic changing network and it is capable of communicating with each other efficiently where all the nodes perform a dual role as that of a transmitter and a receiver. MANETs do not use any centralized administration for communication. The performance of a MANET can be further enhanced by adapting a cluster mechanism with the help of CEAACK to provide security from penetrators. In this paper we propose a new improved ant colony optimization algorithm with two strategies to reduce the overhead in communication by predicting mobility of node and cluster formation. Firstly, a dynamic mechanism is designed for determining one or more heuristic parameters for improving the performance of the MANET. Secondly a dynamic list of nodes are maintained which helps in forming clusters and electing the cluster head faster. In addition a dynamic broadcast approach algorithm is incorporated to provide the information about the status of the nodes to the hybrid fuzzy-ant colony algorithm. This approach ensures low maintenance cost and is expected to be robust against node failures and network topology changes. The positive outcome of these two techniques consumes low energy and in the process provides better efficiency in data transmission in MANETs. It also achieves correct delivery of packets without unnecessary delay.     

Mobile IPv6-based ad hoc networks: its development and application

The Internet protocol version 6 (IPv6)-enabled network architecture has recently attracted much attention. In this paper, we address the issue of connecting mobile ad hoc networks (MANETs) to global IPv6 networks, while supporting IPv6 mobility. Specifically, we propose a self-organizing, self-addressing, self-routing IPv6-enabled MANET infrastructure, referred to as IPv6-based MANET. The proposed self-organization addressing protocol automatically organizes nodes into tree architecture and configures their global IPv6 addresses. Novel unicast and multicast routing protocols, based on longest prefix matching and soft state routing cache, are specially designed for the IPv6-based MANET. Mobile IPv6 is also supported such that a mobile node can move from one MANET to another. Moreover, a peer-to-peer (P2P) information sharing system is also designed over the proposed IPv6-based MANET. We have implemented a prototyping system to demonstrate the feasibility and efficiency of the IPv6-based MANET and the P2P information sharing system. Simulations are also conducted to show the efficiency of the proposed routing protocols.     

Crossing Over the Bounded Domain: From Exponential to Power-Law Intermeeting Time in Mobile Ad Hoc Networks

Intermeeting time between mobile nodes is one of the key metrics in a mobile ad hoc network (MANET) and central to the end-to-end delay of forwarding algorithms. It is typically assumed to be exponentially distributed in many performance studies of MANET or numerically shown to be exponentially distributed under most existing mobility models in the literature. However, recent empirical results show otherwise: The intermeeting time distribution, in fact, follows a power-law. This outright discrepancy potentially undermines our understanding of the performance tradeoffs in MANET obtained under the exponential distribution of the intermeeting time and, thus, calls for further study on the power-law intermeeting time including its fundamental cause, mobility modeling, and its effect. In this paper, we rigorously prove that a finite domain, on which most of the current mobility models are defined, plays an important role in creating the exponential tail of the intermeeting time. We also prove that by simply removing the boundary in a simple two-dimensional isotropic random walk model, we are able to obtain the empirically observed power-law decay of the intermeeting time. We then discuss the relationship between the size of the boundary and the relevant timescale of the network scenario under consideration. Our results thus provide guidelines on the mobility modeling with power-law intermeeting time distribution, new protocols including packet-forwarding algorithms, as well as their performance analysis.