一种跨平台的自组网路由协议实现框架

为了减少不同平台上自组网(MANET)路由协议的重复实现和保证协议在不同平台下实现的正确性与一致性,设计并实现了一种可以在Windows、Linux,以及NS-2模拟器上运行的自组网路由协议框架,并用典型的自组网反应式路由协议AODV对其可行性进行了验证。该框架设计中将协议实体与周边环境抽象开来的方法具有通用性,可以适用于其他自组网路由协议甚至其他网络协议(例如TCP),也可以扩展支持其他操作系统。     

基于LoRa自组网的电能采集系统设计与实现

为了实现用电设备运行状况的远程监测,需要对设备运行时的电能参数进行采集并上报至云平台。针对上述目的,本项目设计了一种基于LoRa自组网技术的电能采集系统,整个系统主要由数据采集节点和集中器组成。数据采集节点采用RN8209电能计量芯片实现负载电能数据的精确采集,并通过LoRa通信模块将数据发送至集中器。集中器采用了基于NB-IoT通信模块和LoRa通信模块的双模组设计,通过LoRa模块接收节点上报的数据,并通过NB-IoT模块转发至物联网云平台。本系统利用LoRa载波侦听技术设计了基于CSMA/CA的星型自组网络,实现了节点与集中器间的无线通信,适用于低成本、小规模的远程电能数据采集系统。通过实验验证,该方案的数据采集功能、LoRa自组网通信功能和NB-IoT通信功能均能够正常实现,达到了设计目标。     

移动自组网AODV路由协议的设计与实现

针对目前移动自组网路由协议的研究,主要以NS2等网络仿真工具为实验手段的不足,本文详细介绍了在Linux平台上,使用无线网络接口,设计移动自组网AODV路由协议,为进一步研究移动自组网的相关性能,提供平台基础。     

一个简洁高效的Ad Hoc移动自组网络仿真工具

针对目前Ad Hoc移动自组网络仿真系统使用复杂、难以掌握的问题，首先采用面向对象的方法对移动自组网的仿真需求进行了分析，指出Ad Hoc网络仿真需要模拟的几个关键特征，在此基础上完成了面向对象的仿真工具建模，并使用VC＋＋实现了仿真模型。工具设计简洁，易于使用并提供了扩展接口。最后利用仿真环境模拟并分析了两种基于移动自组网的证书管理方案，得出关键的仿真数据，通过对比专业仿真系统的结果可知工具具备较好的可信度，可以满足Ad Hoc网络基本的仿真需求。     

ZigBee结合GPRS的无线自组网的数据传输系统

为解决数据通过无线自组网远距离传输所存在的问题,设计了ZigBee结合GPRS的数据传输系统。介绍了系统的硬件架构以及终端通过路由转发数据的过程,同时对终端节点发送、路由转发及数据上报到网关等环节进行了软件设计;最后对系统运行进行了测试。测试结果显示,数据可以稳定地从终端节点传输到服务器端,系统有效地实现了数据在无线自组网中的远程传输。     

基于群组移动模型的OLSR协议性能仿真与评估

在研究移动自组网移动模型和无线路由协议的基础上,选取移动自组网中具有代表性的参考点群移动模型,基于ns2网络模拟平台,以参考点群组移动模型生成移动场景文件,应用层使用cbr数据流量,对OLSR无线路由协议在不同参数条件下的性能进行了模拟测试。通过对测试结果数据的详细分析,总结得出了OLSR无线路由协议在参考点群移动模型下端到端时延、报文交付率和路由负载三个方面的特点。为进一步研究移动自组网下基于OLSR协议的各种应用提供参考。     

基于跨层设计的无线自组网方案

首先详细描述了目前无线自组网现状及问题,然后基于跨层设计思想提出一种无线节点组网方案,尤其对MAC层、网络层的实现方案进行了详细描述,最后进行样机实现并搭建半实物仿真环境进行了仿真试验,仿真结果显示该组网方案在网络吞吐量方面比传统组网模式有显著提升.     

移动自组网中基于任务分配的入侵检测

移动自组网具有传统计算机网络及无线通信网络两方面的复杂性。提出移动自组网中基于任务分配的网络入侵检测方案,并描述各主要功能模块的实现,通过模拟实验对方案进行验证。实验结果显示,该方案除了能基本实现传统移动自组网络IDS的功能之外,还能有效节约网络系统的资源,提高网络移动节点的可用性。     

机器人自组网的运动控制模型仿真研究

机器人自组网具有较高的军事和民用价值;基于机器人通用运动学模型,对传统自组网的节点运动模型——随机路点和随机方向移动模型进行了修改,为机器人自组网中的节点建立了运动控制模型,并建立了机器人自组网的网络模型,对几种运动模型进行了仿真分析;结果表明,在机器人自组网的仿真场景中网络性能有所恶化;达到了较为真实地仿真机器人自组网的目的,得出的结论对机器人自组网的仿真研究具有一定的参考价值。     

车载自组网动态频谱分配技术研究进展

为了提高车载自组网的性能和频谱利用率,多接口动态频谱分配技术成为车载自组网的研究热点。介绍了车载自组网动态频谱分配算法的关键设计基础,对多接口多信道网络技术的发展现状进行了分类阐述,对车载自组网动态频谱分配技术的研究进行了展望。     

Maintaining a ring structure for mobile ad hoc computing

In a mobile ad hoc (multi-hop) wireless network, the logical structure of a ring is likely to become volatile or expensive to maintain over time due to changeable network topology. Additional adverse effects take place when a process joins or leaves the computation in the presence of mobility. This paper presents a distributed algorithm that adapts a ring among mobile nodes to the network dynamics to reflect overall communication efficiency. This is achieved by modifying the ring structure in a localized, mutual exclusive fashion, thereby allowing for concurrent segment-wise modifications to proceed. Remarkably our proposal operates without global knowledge of the logical structure and can be embodied as an underlying protocol stratum that supports transparent deployments of conventional algorithms in mobile environment. Subsequent to correctness proof, simulation results show that our proposal is promising in several regards.     

Safeguarding ad hoc networks with a self-organized membership control system

One of the key challenges for ad hoc networks is providing distributed membership control. This paper introduces a self-organized mechanism to control user access to ad hoc networks without requiring any infrastructure or a central administration entity. Our mechanism authenticates and monitors nodes with a structure that we call controller set, which is robust to the dynamic network membership. We develop analytical models for evaluating the proposal and validate them through simulations. The analysis shows that the proposed scheme is robust even to collusion attacks and provides availability up to 90% better than proposals based on threshold cryptography. The performance improvement arises mostly from the controller sets capability to recover after network partitions and from the identification and exclusion of malicious nodes.     

基于门限完全分布式密钥管理方案

adhoc网络作为一种无线移动网络正成为网络研究中的热点之一。针对移动adhoc网络的特性和对目前已有的移动adhoe网络密钥管理方案的分析,提出了一种基于信任图和门限密码技术的全分布、自组织的移动adhoc网络密钥管理新方案。该方案允许节点发布公钥证书并且通过证书链实施认证,有效地解决了网络节点之间的信任,同时又阻止恶意节点发布错误公钥证书欺骗认证服务。该方案具有较高的可靠性、扩展性和安全性,适用于大规模移动ad hoc网络。     

Scalability of routing methods in ad hoc networks

In an ad hoc network each host (node) participates in routing packets. Ad hoc networks based on 802.11 WLAN technology have been the focus of several prior studies. These investigations were mainly based on simulations of scenarios involving up to 100 nodes (usually 50 nodes) and relaxed (too unrealistic) data traffic conditions. Many routing protocols in such setting offer the same performance, and many potential problems stay undetected. At the same time, an ad hoc network may not want (or be able) to limit the number of hosts involved in the network. As more nodes join an ad hoc network or the data traffic grows, the potential for collisions and contention increases, and protocols face the challenging task to route data packets without creating high administrative load. The investigation of protocol behavior in large scenarios exposes many hidden problems. The understanding of these problems helps not only in improving protocol scalability to large scenarios but also in increasing the throughput and other QoS metrics in small ones. This paper studies on the example of AODV and DSR protocols the influence of the network size (up to 550 nodes), nodes mobility, nodes density, suggested data traffic on protocols performance. In this paper we identify and analyze the reasons for poor absolute performance that both protocols demonstrate in the majority of studied scenarios. We also propose and evaluate restructured protocol stack that helps to improve the performance and scalability of any routing protocol in wireless ad hoc networks.     

A Termination Detection Protocol for Use in Mobile Ad Hoc Networks

As devices become smaller and wireless networking technologies improve, the popularity of mobile computing continues to rise. In today's world, many consider devices such as cell phones, PDAs, and laptops as essential tools. As these and other devices become increasingly independent of the wired infrastructure, new kinds of applications that assume an ad hoc network infrastructure are being deployed. Their development forces software engineers to revisit well understood problems in a setting in which existing solutions are no longer working. This paper illustrates one such attempt by focusing on an important problem in distributed computing, termination detection in diffusing computations, in an ad hoc network environment. We formulate an algorithmic solution amenable to usage in mobile ad hoc networks. Along the way, we highlight several important software engineering concerns one must address and design strategies one might employ in a mobile setting.     

A survey of secure wireless ad hoc routing

Ad hoc networks use mobile nodes to enable communication outside wireless transmission range. Attacks on ad hoc network routing protocols disrupt network performance and reliability. The article reviews attacks on ad hoc networks and discusses current approaches for establishing cryptographic keys in ad hoc networks. We describe the state of research in secure ad hoc routing protocols and its research challenges.     

与无线自组网相结合的配电通信网络延伸方案

针对配电通信网络存在网络盲区的问题,提出一种与无线自组网相结合的配电通信网络延伸方案;介绍了常用的无线自组织网络、WIA网络结构及性能分析、配电通信网络延伸方案的三层结构。该方案利用无线自组织网络的多跳性和自组织性,实现了盲区终端数据的回传。实际应用结果表明,该方案不但成本低、功耗低,且具有数据传输时延短、安全性高等优势。     

Revealing the problems with 802.11 medium access control protocol in multi-hop wireless ad hoc networks

The IEEE 802.11 medium access control (MAC) protocol is a standard for wireless LANs, it is also widely used in almost all test beds and simulations for the research in wireless mobile multi-hop ad hoc networks. However, this protocol was not designed for multi-hop networks. Although it can support some ad hoc network architecture, it is not intended to support the wireless mobile ad hoc network, in which multi-hop connectivity is one of the most prominent features. In this paper, we focus on the following question: can IEEE 802.11 MAC protocol function well in multi-hop networks? By presenting several serious problems encountered in transmission control protocol (TCP) connections in an IEEE 802.11 based multi-hop network, we show that the current TCP protocol does not work well above the current 802.11 MAC layer. The relevant problems include the TCP instability problem found in this kind of network, the severe unfairness problem, and the incompatibility problem. We illustrate that all these problems are rooted in the MAC layer. Furthermore, by revealing the in-depth cause of these problems, we conclude that the current version of this wireless LAN protocol does not function well in multi-hop ad hoc networks. We thus doubt whether the current WaveLAN based system is workable as a mobile multi-hop ad hoc test bed. All the results shown in this paper are based on NS2 simulations, and are compatible with the results from the OPNET simulations.     

LLACA: An adaptive localized clustering algorithm for wireless ad hoc networks

Performance of ad hoc networks dramatically declines as network grows. Cluster formation in which the network hosts are hierarchically partitioned into several autonomous non-overlapping groups, based on proximity, is a promising approach to alleviate the scalability problem of ad hoc networks. In this paper, we propose a localized learning automata-based clustering algorithm for wireless ad hoc networks. The proposed clustering method is a fully distributed algorithm in which each host chooses its cluster-head based solely on local information received from neighboring hosts. The proposed algorithm can be independently localized at each host. This results in a significantly reduction in message overhead of algorithm, and allows cluster maintenance can be locally performed only where it is required. To show the performance of proposed algorithm, obtained results are compared with those of several existing clustering methods in terms of the number of clusters, control message overhead, clustering time, and load standard deviation.