应急通信保障中无线自组网技术的应用研究

无线自组网具有无中心、自配置和快速组网等显著特点,非常适合用于应急通信保障。首先,介绍了当前国内应急通信的现状和存在的问题。然后,概述了以Ad Hoc网络、无线传感网和无线mesh网络为代表的无线自组网的显著特点和技术优势,并举例说明了无线自组网在应急通信保障中的几种具体应用。最后,展望了应急通信网络今后的发展方向。     

无线自组网络的技术研究

随着通信技术的快速发展和人们对通信要求的提高,无线自组织网成为当今网络的重要研究内容。无线自组织网络由几个可移动的无线节点自组织形成的一个多跳、灵活、无中心的网络,这些特点为它在军事和民用通信领域提供了有利保证。文章首先介绍了无线自组网的特点和应用;其次对现有路由协议存在的问题进行了研究;最后针对无线自组网存在的能量消耗,多路径,多播等问题归纳出了的六种方法对系统进行优化,提高了无线自组网络的传输性能。     

一种基于短波和散射通信的自组网新方案

结合地空导弹网络化作战对于通信网络的需求,分析了无线自组网在其中的应用.针对短波通信带宽小、时延大以及信道不稳定的缺点,将对流层散射通信引入到短波自组网中,设计了多信道的无线自组网.控制信道采用短波,数据业务信道采用散射通信,可以满足组网的灵活性和实时的业务传输.最后对短波控制网络在OPNET中进行设计和仿真,分析了不同路由协议的性能.所做工作可为地空导弹网络化作战的通信网络的构建提供参考.     

基于无线传感器网络滴灌控制系统的设计

提出了一种基于无线传感器网络滴灌控制系统节水滴灌控制系统的设计方法,给出了系统的网络体系结构、协调器节点和传感器节点的硬件和软件设计方案,以及无线传感器网络的自组网和数据采集传输的过程。通过反馈的数据表明,系统能够根据监测植物土壤水分的变化,对植物进行自动节水滴溉。     

透过式自组传感网络的设计及其在网格社区领域的应用

设计了一种透过式自组传感网络,各节点在进行入网时无需考虑射频芯片的收发协议和配置方法,每个终端传输节点均具备自动路由功能,可通过无线芯片将无线协议等价于有线协议,即插即用。设计的传感网络降低了通信网络的软硬件和研发成本,多跳路由功能保证了通信距离和准确性。可在建筑物密集的环境下实现1 000 m范围内动态实时数据传输,在网格社区领域具有广泛应用。     

基于ZigBee的滴灌自动控制系统的设计

提出了一种基于ZigBee的节水滴灌控制系统的设计方法,给出了系统的网络体系结构、协调器节点和传感器节点的硬件和软件设计方案,以及无线传感器网络的自组网和数据采集传输的过程。通过无线传感器反馈的数据,系统能够根据监测植物土壤水分的变化,对植物进行自动节水滴溉。     

基于Zigbee技术的监管平台的系统设计与实现

基于无线传感器网络设计一套战地装备智能监控系统,该系统由集成特定传感器的多个监控节点和配套通信及数据处理软件构成。系统结合智能传感器网络技术、无线射频（RFID）技术和有线通信网络技术,可在战地恶劣条件下快速构建一个以无线自组网为终端、以内网为骨干的混合网络。系统通过监控节点协作地感知、采集和处理网络覆盖区域内特定对象的信息,实现重要装备自动注册、关键设备运行状态自动监测、前指驻地周边环境定位、监控和报警等多种功能。     

刍议移动自组网通信智能感知技术

自组网络是一种不需要依靠事前准备的基础通信设备,它不需要明确的中心控制点,抗毁性能优良,具有繁琐的多跳无线、分布式的无线网络。联想自组网本身以及无线电磁环境的相关特征,本文结合一种具体波形不相同执行流程特征提供了智能感知规划,保证设备在接收信号最好、噪声干扰最低等频点上面工作,进而提升通信优良频点的利用效率,进而获取更为优质的通信体验。     

博物馆温湿度监测系统设计

该文设计了一种基于433 MHz频段无线传感器网络(WSN)的馆藏文物温湿度监测系统。系统以SI4432无线射频收发器和STM8L微处理器为核心,采用SHT15采集温湿度信息。通过设计的组网通信协议使系统具有自组网、路由自动查找及低功耗等特点。实验表明,系统能准确地监测当前环境温湿度并将采集数据发送给监控主机,且误码率及丢包率较低,通过监控机可实现对温湿度、网络状态等信息的采集、管理和分析。     

高生存性异构应急通信网络的设计与分析

针对应急通信的特点和要求,基于无线自组网构建的一种高生存性异构应急通信网络,为应急现场提供了一种可靠、灵活的通信支撑平台.首先,说明了异构应急通信网络的特点和生存性要求.然后,重点对高生存性异构应急通信网络的设计进行了阐述和分析,包括组网方式、设计策略和网络结构;最后,探讨了进一步提高应急通信网络可生存性的一些措施.     

一种应用于教学实验的多点无线通信网络的设计和研制

提出了一种基于蓝牙小区域无线接入技术，该技术适用于教学实验的多点无线通信网络的设计和研制。该无线通信网络具备移动自组织(ad hoc)网络的典型特征，并有网络结构清晰、路由算法简洁等待点。运用该多点无线通信网络而设计的无线多点组网实验具备良好的教学功能。     

一种集成ad hoc与蜂窝的4G新型网格（IACG）

在第四代移动通信系统( 4G)中,采用ad hoc网络为核心技术,以满足2 0 1 0年后市场对大容量、高带宽、无缝漫游的需求,是近一两年来全球业界提出的一种崭新的技术思路和发展方向。本文根据4G工程原则和ad hoc网络框架,构建了一种新型的集成ad hoc与蜂窝网格( Integrated Cellular and Ad hoc Grid,IACG)。在此基础上,研究提出了其容量提高方案、移动预测模型、网络动态变化中的容错设计、基于代理的可靠路由协议以及低功耗无线多层优化协议,解决了当前ad hoc网络如何在移动通信领域走向实用化的关键技术     

Securing ad hoc networks

Ad hoc networks are a new wireless networking paradigm for mobile hosts. Unlike traditional mobile wireless networks, ad hoc networks do not rely on any fixed infrastructure. Instead, hosts rely on each other to keep the network connected. Military tactical and other security-sensitive operations are still the main applications of ad hoc networks, although there is a trend to adopt ad hoc networks for commercial uses due to their unique properties. One main challenge in the design of these networks is their vulnerability to security attacks. In this article, we study the threats on ad hoc network faces and the security goals to be achieved. We identify the new challenges and opportunities posed by this new networking environment and explore new approaches to secure its communication. In particular, we take advantage of the inherent redundancy in ad hoc networks-multiple routes between nodes-to defend routing against denial-of-service attacks. We also use replication and new cryptographic schemes, such as threshold cryptography, to build a highly secure and highly available key management service, which terms the core of our security framework     

Stable routing algorithm for mobile ad hoc networks using mobile agent

Wireless ad hoc networks are growing important because of their mobility, versatility, and ability to work with fewer infrastructures. The mobile ad hoc network is an autonomous system consisting of mobile nodes connected with wireless links. Establishing a path between two nodes is a complex task in wireless networks. It is still more complex in the wireless mobile ad hoc network because every node is no longer as an end node and an intermediate node. In this paper, it focuses on design of connectionless routing protocol for the wireless ad hoc networks based on the mobile agent concept. The proposed model tries to discover the best path taking into consideration some concerns like bandwidth, reliability, and congestion of the link. The proposed model has been simulated and tested under various wireless ad hoc network environments with the help of a different number of nodes. The results demonstrate that the proposed model is more feasible for providing reliable paths between the source and destination with the minimum control message packets over the network. It has delivered more number of packets to the destination over the network. Copyright © 2012 John Wiley & Sons, Ltd.     

Guest editorial - Delay and disruption tolerant wireless communication

The eight papers in this special issue focus on delay and disruption tolerant wireless communication. The papers cover routing and network coding for spare mobile ad hoc networks, cross-layer design for sensor networks, satellite communication, and DTN architectural issues.     

一种基于北斗的混合式无线自组网系统设计

在林业、消防、治安反恐、军事等领域,任务单元之间灵活、可靠的动态自组网数据传递,是提高一体化指挥能力和快速响应能力的关键所在。传统的无线局域自组网技术易受距离、遮挡等条件限制,在大区域、有遮挡条件下的应用有一定局限性。文章基于北斗系统定位和短报文通信能力,结合无线局域自组网技术,利用北斗应用终端设备为骨干构建了分层编组逻辑网络,有效扩大了覆盖范围和增强了组网可靠性。不同参数的网络变化与修复过程的仿真表明,该系统能够实现动态环境中网络修复与重组,提供可靠通信保障,解决了多种场合下所需的精确、无间断一体化指挥要求。     

Energy-Efficient Routing Algorithms Using Directional Antennas for Mobile Ad Hoc Networks

Power consumption is an important issue in the wireless ad hoc networking environment. In this paper, we present several energy-efficient routing algorithms using directional antennas for wireless ad hoc networks. These algorithms are simple to implement and are distributed and can be applied to mobile environments. We evaluate how directional antennas improve system throughput. We study the influence of the battery recovery effect and mobility on the network throughput during a network lifetime. We also present an algorithm that exploits the broadcast nature of the wireless communication environment to improve end-to-end bit error performance for a Rayleigh fading channel.     

OMAR: Utilizing Multiuser Diversity in Wireless Ad Hoc Networks

One of the most promising approaches to improving communication efficiency in wireless communication systems is the use of multiuser diversity. Although it has been widely investigated and shown feasible and efficient in cellular networks, there is little work for the ad hoc networks, especially in real protocol and algorithm design. In this paper, we propose a novel scheme, namely, the opportunistic medium access and auto rate (OMAR), to efficiently utilize the shared medium in IEEE 802.11-based ad hoc networks by taking advantage of diversity, distributed scheduling, and adaptivity. In an ad hoc network, especially in a heterogeneous ad hoc network or a mesh network, some nodes may need to communicate with multiple one-hop nodes. We allow such a node with a certain number of links to function as a clusterhead to locally coordinate multiuser communications. We introduce a CDF-based (cumulative distribution function) K-ary opportunistic splitting algorithm and a distributed stochastic scheduling algorithm to resolve intra and intercluster collisions, respectively. Fairness is formulated and solved in terms of social optimality within and across clusters. Analytical and simulation results show that our scheme can significantly improve communication efficiency while providing social fairness     

窄带无线自组网在应急语音通信中的实战性应用研究

在现代通信技术快速发展的背景下,应急语音通信作为应对突发自然灾害的重要手段,近年来得到了广泛重视。结合应急通信的实战需求,探讨了新一代窄带自组网通信技术的在应急通信领域的创新应用。根据我国实际情况提出了现有窄带应急通信的问题和需求,然后介绍并分析了窄带自组网的原理和特点,其具有通信覆盖面积广、抗毁性强、维护简单以及成本低等优势,极好地满足了目前偏远地区窄带应急语音通信的需要。最后,结合实际案例阐述了窄带自组网作为应急语音通信网的应用优势,初步证明了该应用的可行性。     

Optimal resource allocation in wireless ad hoc networks: a price-based approach

The shared-medium multihop nature of wireless ad hoc networks poses fundamental challenges to the design of effective resource allocation algorithms that are optimal with respect to resource utilization and fair across different network flows. None of the existing resource allocation algorithms in wireless ad hoc networks have realistically considered end-to-end flows spanning multiple hops. Moreover, strategies proposed in wireline networks are not applicable in the context of wireless ad hoc networks, due to their unique characteristics of location-dependent contention. In this paper, we propose a new price-based resource allocation framework in wireless ad hoc networks to achieve optimal resource utilization and fairness among competing end-to-end flows. We build our pricing framework on the notion of maximal cliques in wireless ad hoc networks, as compared to individual links in traditional wide-area wireline networks. Based on such a price-based theoretical framework, we present a two-tier iterative algorithm. Distributed across wireless nodes, the algorithm converges to a global network optimum with respect to resource allocations. We further improve the algorithm toward asynchronous network settings and prove its convergence. Extensive simulations under a variety of network environments have been conducted to validate our theoretical claims.