基于CBR与TCP移动白组网路由协议分析

移动自组网是由无线移动主机组成的没有基础设施或集中管理中心的临时性网络。在其组建应用过程中,路由协议起着重要的作用。文中基于仿真软件NS2对移动自组网三种典型路由协议DSDV、DSR、TORA在TCP与CBR业务下的性能进行了比较分析。仿真结果表明,在发送速率144kb／s时,DSR与DSDV性能优于TORA,且TCP业务性能优于CBR业务。     

Ad Hoc网络路由协议比较与性能评价

无线AdHOC网络的应用越来越广泛。由于在移动环境中节点韵频繁移动．使得现有网络的路由协议不能满足用户的需求，为此．有许多的研究机构开始关注无线路由协议及算法，提出了多个无线AdHOC路由解决方案。本文介绍和分析了当前AdHOC网络中的主要路由协议算法，使用网络仿真软件NS2评价AdHoc路由协议中的DSR．AODV，DSDV协议．编写了用于仿真实现的脚本程序，并对仿真结果进行比较和性能评价。本文的仿真是在5个和30个无线节点的网络拓扑结构中进行．对整个传输过程产生的仿真Trace文档处理、分析．得到DSR．AODV，DSDV路由协议的性能比较．由此得出不同协议的适用范围和协议特性。     

基于战术互联子网的路由协议性能仿真比较

本文对基于移动Ad Hoc网络的营连以下战术互联子网的网络环境以及应用业务类型特点进行了分析,通过OPNET仿真软件对AODV、DSR和OLSR路由协议在CBR、FrP和Voice三种不同业务类型下进行了仿真,分析了路由协议的平均端到端延时、平均吞吐量和路由控制开销.仿真结果表明,在营连以下战术互联子网在进行战场态势感知任务时,AODV和OLSR协议性能较好;而进行语音话务任务时,OLSR比其AODV和DSR协议性能好.     

基于多节点数据检测的无线接入协议设计

移动自组织网络在专用通信领域中得到广泛重视,如何提高其媒体接入效率是研究的热点。文中针对移动自组织网络中多节点共享资源时媒体接入的频谱利用率和接入效率问题,基于多用户检测理论设计和实现了多节点共享物理资源的媒体接入协议,与传统CSMA/CA协议相比,提高了节点并发传输数量,频谱效率改善可达4.28倍。     

复杂网络环境下的DSR路由协议性能仿真

DSR是用于多跳无线Ad hoc网络的一个简单高效的路由协议,DSR协议由路由发现和路由维持两部分组成,允许节点在Ad hoc网络中发现、维持到任意节点的源路由.文章详细介绍了DSR协议的特点并利用Opnet Modeler 10.5构建了小规模(50节点)和大规模(100节点)复杂的(所有节点同时移动、所有节点既是源节点又是目的节点)移动自组网模型,通过改变节点移动速度及发送分组大小,对DSR路由算法的平均路由发现时间、平均路由长度、吞吐量、数据分组平均端到端的时延、及分组交付率在两种场景下进行了仿真分析和性能比较.     

无线自组织网中VoIP性能研究

目前,VoIP技术及其业务迅速发展,在无线自组织网络中有广泛的应用,有必要对于VoIP在无线自组网中的传输进行分析研究。利用NS-2作为仿真工具对G.711编码标准下多跳无线自组织网中VoIP的传输进行仿真,使用802.11MAC层协议和AODV路由层协议。实验结果表明,无线自组织网络环境下VoIP系统性能(包括丢包率、时延等)受到多跳影响。     

无线白组织网中VoIP性能研究

目前,VoIP技术及其业务迅速发展,在无线自组织网络中有广泛的应用,有必要对于VoIP在无线自组网中的传输进行分析研究。利用NS-2作为仿真工具对G.711编码标准下多跳无线自组织网中VoIP的传输进行仿真,使用802．11MAC层协议和AODV路由层协议。实验结果表明,无线自组织网络环境下voIP系统性能（包括丢包率、时延等）受到多跳影响。     

Ad Hoc网络DSR路由协议仿真性能分析

移动Ad Hoc网络是随着无线通信技术的快速发展而出现的一种新型网络。目前,它的应用越来越广泛。在介绍移动Ad Hoc网络的相关技术后,对动态源路由协议(DSR)进行了研究,通过计算机仿真,在不同的网络负荷、节点移动性条件下,对移动Ad Hoc网络的性能进行了分析,仿真结果表明DSR路由协议对于移动环境下的动态路由适应性较好。     

无线自组网竞争类MAC协议分析及研究

无线自组织网络是一种无基础设施的移动网络,并且每个节点的业务多以突发业务为主,因此信道资源分配适用于采用竞争方式。本文在对无线自组网各种典型竞争类MAC协议进行分析及探讨的基础上,采用Opnet仿真建模环境,创建出各协议的状态分析模型,并在此基础上对各协议的性能优劣进行了比较总结。论文对无线自组网各协议仿真建模研究及选择高效适用的MAC技术方案具有实际参考价值。     

无线Ad hoc网络机会路由的实现与仿真

在无线自组织网络中,路由协议对网络的性能起着关键性作用。然而由于无线信道的不稳定性经常造成通信中断而需重建路由,使自组织网传统路由协议的效率大大降低。提出了一种应用于无线自组织网络的机会路由协议（WAOR）,利用无线信道的广播特性和多径传输来增强链路的可靠性。采用网络仿真器NS2的仿真结果表明,WAOR的性能优于传统的动态源路由协议（DSR）和自组织网按需平面距离矢量路由协议（AODV）。     

On the effect of group mobility to data replication in ad hoc networks

The growth in wireless communication technologies attracts a considerable amount of attention in mobile ad hoc networks. Since mobile hosts in an ad hoc network usually move freely, the topology of the network changes dynamically and disconnection occurs frequently. These characteristics make it likely for a mobile ad hoc network to be separated into several disconnected partitions, and the data accessibility is hence reduced. Several schemes are proposed to alleviate the reduction of data accessibility by replicating data items. However, little research effort was elaborated upon exploiting the group mobility where the group mobility refers to the phenomenon that several mobile nodes tend to move together. In this paper, we address the problem of replica allocation in a mobile ad hoc network by exploring group mobility. We first analyze the group mobility model and derive several theoretical results. In light of these results, we propose a replica allocation scheme to improve the data accessibility. Several experiments are conducted to evaluate the performance of the proposed scheme. The experimental results show that the proposed scheme is able to not only obtain higher data accessibility, but also produce lower network traffic than prior schemes.     

A bandwidth allocation/sharing/extension protocol for multimediaover IEEE 802.11 ad hoc wireless LANs

We propose a novel bandwidth allocation/sharing/extension (DBASE) protocol to support both asynchronous traffic and multimedia traffic with the characteristics of variable bit rate (VBR) and constant bit rate (CBR) over IEEE 802.11 ad hoc wireless local area networks. The overall quality of service (QoS) will be guaranteed by DBASE. The designed DBASE protocol will reserve bandwidth for real-time stations based on a fair and efficient allocation. Besides, the proposed DBASE is still compliant with the IEEE 802.11 standard. The performance of DBASE is evaluated by analysis and simulations. Simulations show that the DBASE is able to provide almost 90% channel utilization and low packet loss due to delay expiry for real-time multimedia services     

Scalability in Global Mobile Information Systems (GloMo): Issues,Evaluation Methodology and Experiences

The GloMo (Global Mobile Information Systems) project¹ has focused on developing new wireless ad hoc networking technologies. These new technologies rely on a broad and varied set of techniques to help cope with the problems inherent in the wireless environment. One of the most critical design elements of all the various technologies is their applicability in large scale deployments. The main objective of our work is to develop and implement a simulation methodology to help evaluate the scalability of these new ad hoc networking technologies and gain some insight into the various aspects of ad hoc network performance scalability issues. To achieve that we have developed a scalability performance evaluation framework and plan, that spans all the various dimensions of scalability: size (number of nodes and density), traffic, operational environment (i.e. propagation models, terrain etc.), mobility. For demonstration purposes we have applied this process on a representative integrated protocol suite designed to provide communication services in mobile ad hoc wireless networks. The corresponding results of the two most critical aspects of scalability properties in tactical networks (i.e. network initialization time and traffic scalability) are also presented here, and demonstrate that a very extensive evaluation of the corresponding scalability metrics under a combination of the various scalability dimensions defined in this paper, is necessary in order to provide an in-depth analysis of the scalability properties in wireless mobile ad hoc networking environments.     

A Self-Repairing Tree Topology Enabling Content-Based Routing in Mobile Ad Hoc Networks

Content-based routing (CBR) provides a powerful and flexible foundation for distributed applications. Its communication model, based on implicit addressing, fosters decoupling among the communicating components, therefore meeting the needs of many dynamic scenarios, including mobile ad hoc networks (MANETs). Unfortunately, the characteristics of the CBR model are only rarely met by available systems, which typically assume that application-level routers are organized in a tree-shaped network with a fixed topology. In this paper, we present COMAN, a protocol to organize the nodes of a MANET in a tree-shaped network able to 1) self- repair to tolerate the frequent topological reconfigurations typical of MANETs and 2) achieve this goal through repair strategies that minimize the changes that may impact the CBR layer exploiting the tree. COMAN is implemented and publicly available. Here, we report about its performance in simulated scenarios, as well as in real-world experiments. The results confirm that its characteristics enable reliable and efficient CBR on MANETs.     

On-demand power management for ad hoc networks

Battery power is an important resource in ad hoc networks. It has been observed that in ad hoc networks, energy consumption does not reflect the communication activities in the network. Many existing energy conservation protocols based on electing a routing backbone for global connectivity are oblivious to traffic characteristics. In this paper, we propose an extensible on-demand power management framework for ad hoc networks that adapts to traffic load. Nodes maintain soft-state timers that determine power management transitions. By monitoring routing control messages and data transmission, these timers are set and refreshed on-demand. Nodes that are not involved in data delivery may go to sleep as supported by the MAC protocol. This soft state is aggregated across multiple flows and its maintenance requires no additional out-of-band messages. We implement a prototype of our framework in the ns-2 simulator that uses the IEEE 802.11 MAC protocol. Simulation studies using our scheme with the Dynamic Source Routing protocol show a reduction in energy consumption near 50% when compared to a network without power management under both long-lived CBR traffic and on–off traffic loads, with comparable throughput and latency. Preliminary results also show that it outperforms existing routing backbone election approaches.     

PACMAN: passive autoconfiguration for mobile ad hoc networks

Mobile ad hoc networks (MANETs) enable the communication between mobile nodes via multihop wireless routes without depending on a communication infrastructure. In contrast to infrastructure-based networks, MANET's support autonomous and spontaneous networking and, thus, should be capable of self-organization and -configuration. This paper presents passive autoconfiguration for mobile ad hoc network (PACMAN), a novel approach for the efficient distributed address autoconfiguration of mobile ad hoc networks. Special features of PACMAN are the support for frequent network partitioning and merging, and very low protocol overhead. This is accomplished by using cross-layer information derived from ongoing routing protocol traffic, e.g., address conflicts are detected in a passive manner based on anomalies in routing protocol traffic. Furthermore, PACMAN assigns Internet protocol (IP) addresses in a way that enables their compression, which can significantly reduce the routing protocol overhead. The performance of PACMAN is analyzed in detail based on various simulation results.     

Efficient on-demand routing for mobile ad hoc wireless access networks

In this paper, we consider a mobile ad hoc wireless access network in which mobile nodes can access the Internet via one or more stationary gateway nodes. Mobile nodes outside the transmission range of the gateway can continue to communicate with the gateway via their neighboring nodes over multihop paths. On-demand routing schemes are appealing because of their low routing overhead in bandwidth restricted mobile ad hoc networks, however, their routing control overhead increases exponentially with node density in a given geographic area. To control the overhead of on-demand routing without sacrificing performance, we present a novel extension of the ad hoc on-demand distance vector (AODV) routing protocol, called LB-AODV, which incorporates the concept of load-balancing (LB). Simulation results show that as traffic increases, our proposed LB-AODV routing protocol has a significantly higher packet delivery fraction, a lower end-to-end delay and a reduced routing overhead when compared with both AODV and gossip-based routing protocols.     

Multipath routing in mobile ad hoc network with probabilistic splitting of traffic

Multipath routing is a burning issue in mobile ad hoc network due to its various advantages over single path routing. Some of these advantages are load balancing, bandwidth aggregation, and fault tolerance. Multipath routing means multiple paths exist between source and destination pair. Many works discussed in section 2 addressed queuing delays, but none of them suggested queuing delay for multiple path deliveries of data in mobile ad hoc network context. In this paper, we have designed a mathematical model to compute delay and throughput for multipath. Our model follow the network of M/M/1 queues, and we have applied Burke’s theorem to calculate the queuing delay of the packet in mobile network scenario. This model can be used to estimate delay and throughput of an individual path. Further, through the analysis the best path for data delivery out of available multiple paths as well as the multipath path can be used simultaneously for data delivery to the destination. Simulation result shows that splitted traffic multiple paths outperform splitted traffic. Therefore, our model is useful for design and analysis of ad hoc network. The simulation work has been carried out in Qualnet simulator.