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远程再编程是有效维护和管理部署后传感网络的重要手段,但要求更新的代码可靠且能量有效地传送到网络中的所有节点.提出一种基于OLSR的传感网络再编程可靠与能量有效传输协议,该协议利用ADV消息中的"下次ADV发送间隔"参数t和传输的代码段数C,变传统的ADVREQDATA三次握手顺序传输为ADVDATA两次握手非顺序传输;并从低层OLSR协议形成的MPR集中选择下级广播节点,有效地减少了广播的节点数,从而降低了能量开销;事后还能统计出实际参与代码更新的节点数.性能分析与模拟实验表明:该协议在节点完全更新代码率、平均延时、能量消耗等方面优于传统的PSFQ. 相似文献
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无线再编程就是对布置在现场的传感器节点进行远程程序代码更新.它对于无线传感器网络的开发、部署以及维护至关重要.大对象(large object)数据分发协议是无线再编程技术的基础.Deluge协议是一个为支持无线再编程而设计的代码分发协议,它在TinyOS平台上已经取得了广泛的应用.将用COOJA仿真器在Contiki... 相似文献
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无线传感器网络(wireless sensor network,WSN)由于容易部署和安装成本低等优势,受到学术界和工业界的广泛关注。然而无线传感器网络的节点在能量、计算能力、存储能力和带宽等方面都存在很大的局限性,复杂的传统网络路由协议无法直接应用到该网络中,因而简单高效的路由协议成为无线传感器网络的研究重点。为了延长传感器的工作时间,文章基于增强学习算法提出一种平衡无线传感器网络生命周期的路由协议Q-WRP。该协议综合考虑了节点的能量、到汇聚节点的跳数、传输时延等信息,为每个转发节点分配计算一个转发质量(即Q值),最终根据各转发节点Q值的大小选择出最优的转发路径。NS2仿真结果表明,该算法延迟了网络第一个死亡节点的出现时间,可以有效平衡网络节点的生命周期。 相似文献
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为提高传感器网络的传输可靠性,提出一种基于网格模型的可靠传输协议。该协议利用网络大小和节点传输距离将网络划分成若干网格。引入随机丢包模型,运用源节点的位置、能耗等信息,在源节点和Sink间确定中间点坐标,再以中间点为圆心的圆形区域内找到距离Sink最近的、可靠的下一跳转发点转发数据包,转发点覆盖全网格,非转发点休眠。理论分析和仿真实验表明,与AOMDV协议相比,该协议具有较高的可靠性且能耗较低,可有效避免广播风暴等问题。 相似文献
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无线传感器网络中一种负载均衡的跳跃式路由协议 总被引:2,自引:2,他引:0
如何实现能量的高效利用,延长网络的生命周期一直是无线传感器网络研究的热点.在传统的路由协议中,靠近基站的节点由于要转发其它节点的数据容易过早耗尽能量而失效.本文基于传感器节点传输功率可调这一假设,提出了一种负载均衡的跳跃式路由协议(LBR).协议中每个节点维护K跳的路由表.在需要发送数据时,剩余能量较少的节点将数据发送给下一跳节点,而剩余能量较多的节点可以跨越多跳进行数据传输.从而均衡了节点的能量消耗.模拟结果表明,采用该协议建立的路由,不仅具有延时小,数据传送的路径长度短,维护简单等优点,并且能够改善网络的负载均衡,极大地延长网络的生命周期. 相似文献
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无线传感网的感知节点部署后需要进行软件维护和功能扩展,因此远程代码更新已变成一种不可或缺的服务。在分析MOAP、Deluge、Ripple等代码分发协议的基础上,设计了一种高可靠、低能耗、低存储、低延迟的多跳代码更新机制Air_update。该机制通过重新设计Bootloader来保证加载代码镜像的正确性、完整性以及节点重编程异常后的可用性;同时,采用子集到子集的分发协议、单播请求的重传策略、滑动窗口的存储管理机制,以减少代码分发的通信量和SRAM、EEPROM的使用量,降低能耗,延长网络的生命周期。最后通过组网实验验证了设计的正确性与有效性。 相似文献
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提出了一种能量有效的具有范围选择的网络再编程协议.该协议首先根据要更新的应用程序、节点的剩余能量、有效度数和节点间的链路质量,选出合适的核心节点,创建虚拟骨干网.然后分两个阶段实现数据传输.在第一阶段软件影像由Sink节点通过流水线的方式,先传输给核心节点;在第二阶段由核心节点并行传输到需要的普通节点.有效地减少了参与再编程的节点数,节省了能量,实现了范围选择.另外,引进协调的睡眠机制,进一步降低节点的能量消耗.性能分析与仿真实验表明:与协议ThreeStages和Aqueduct相比,本协议节省了大约5.6%~24.8%的平均延时和5.1% ~27.7%的能量消耗. 相似文献
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Guilherme Maia Andre L.L. Aquino Daniel L. Guidoni Antonio A.F. Loureiro 《Journal of Parallel and Distributed Computing》2013
Automatic reprogramming is an important and challenging issue in wireless sensor networks (WSNs). A usual approach is the over-the-air programming (OAP), which is a fundamental service based on reliable broadcast for efficient code dissemination. However, existing OAP protocols do not enable the reprogramming of a subset of the sensor nodes in a WSN. Hence, in this work we propose a multicast-based over-the-air programming protocol that considers a small world infrastructure (MOAP-SW). The small world model is used to create shortcuts toward the sink in the communication infrastructure of sensor networks. The endpoints of these shortcuts are more powerful nodes, resulting in a heterogeneous wireless sensor network. Simulation results show the feasibility of the protocol regarding the number of messages transmitted, the energy consumption and the time to reconfigure the network. 相似文献
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《Computer Networks》2007,51(10):2594-2615
Traditional MAC and routing protocols, which are primarily designed for homogeneous networks wherein all nodes transmit with the same power, suffer performance degradations when employed in power heterogeneous networks. The observed degradations are due to link asymmetry, which arises as high power nodes that do not sense the transmissions of low power nodes can potentially initiate transmissions that interfere with the low power communications. Link layer asymmetry in power heterogeneous networks not only disrupts the functioning of the routing protocol in use, but also results in unfairness in medium access. In this paper, we develop a cross-layer framework to effectively address the link asymmetry problem at both the MAC and the routing layers. At the MAC layer, the framework intelligently propagates low power control messages to the higher power nodes, so as to preclude them from initiating transmissions while there are low power communications in progress within their sensing range. At the routing layer, the framework facilitates the efficient use of unidirectional links. We perform extensive simulations to study the performance of our proposed framework in various settings, and show that the overall throughput in power heterogeneous networks is enhanced by as much as 25% over traditional layered approaches. In addition, we show that our schemes are also beneficial in power homogeneous settings, as they reduce the extent of false link failures that arise when the IEEE 802.11 MAC protocol is used. In summary, our framework offers a simple yet effective and viable approach for medium access control and for supporting routing in power heterogeneous ad hoc networks. 相似文献
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比较和分析了自组网络中单路径与多路径的反应式路由协议,在SASR的基础上提出了一个新的多路径路由协议SAMSR。它通过记录重复的RREQ报文以获得更多网络拓扑信息,从而发现更多的可达路径,以及在收到重复的RREP报文后,发回重选报文RSEL保证路径间的节点不相干性。最后通过在NS-2平台上模拟考查其性能,表明SAMSR协议虽然增加了网络开销,但提高了分组抵达率,减少了端到端的路由时延。 相似文献
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在无线传感器网络中,当需要进行软件更新、修复软件Bug 时,重编程协议能够将新程序镜像分发到多跳网络中的全部节点.近来,基于网络编码的重编程协议被用于解决在高损环境下的有效代码分发问题,但对这些协议性能的分析仍有待深入.提出一种基于时间和网络拓扑的能耗分析模型,在模型中综合考虑了页面流水和节点通信距离对协议性能的影响.该模型分析结果与基于网络编码的重编程协议Rateless Deluge 的仿真结果达到了较好的一致性(平均单节点能耗相对误差在0.23%左右),验证了能耗分析模型的有效性.分析结果揭示了基于网络编码重编程过程的网络能耗与网络密度、网络大小和分发镜像页面大小的关系:网络能耗随着网络密度的减小呈上升趋势(能耗与网络密度经拟合呈二次函数关系);网络能耗与网络大小基本呈线性正相关关系(对于n×n 的网格型网络,n从3~10,随着n 的增大,网络能耗的平均增长率为50%),并且随着网络的增大,单节点能耗有所增加(平均增长率为6.9%);页面大小增加时,网络能耗呈下降趋势(平均下降率为11.2%). 相似文献
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主动网络是一种新型的网络体系,不仅可以传送数据包,而且还可以执行数据包中特定的运算任务.主动网络为用户提供了可编程的接口,用户可通过网络中的节点动态地注入所需的服务.而传统网络管理不适应主动网络管理,因而不能发挥主动网络的分布式计算能力.讨论了一种基于节点的主动网络管理模型,分析了该模型的结构、管理机制和设计要点,并对网络拓扑发现和流量进行了分析. 相似文献
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基于位置信息的改进AODV路由算法 总被引:2,自引:0,他引:2
针对AODV协议路由开销较大的问题,提出一种基于位置信息的改进路由协议(GAODV).GAODV利用中间节点重新计算转发角度,保证转发角度内邻居节点数不小于预设门限值,同时还引入基于位置信息的计数器方案,使距离目的节点近的中间节点优先转发路由请求消息,有利于减少转发冗余路由请求信息和降低寻路失败概率.OPNET仿真实验结果表明,GAODV在数据分组投递率、路由开销、总丢包数、端到端时延和平均路由跳数等方面都优于已有算法. 相似文献
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一种异构传感器网络的能量有效路由算法 总被引:1,自引:0,他引:1
无线传感器网络设计能量有效的路由算法是至关重要的.对于不同类型的传感器节点传输不同大小数据包信息以及拥有不同初始能量的异构传感器网络,本文提出了一种适合此传感器网络的D-REECR路由算法,此算法是在之前提出的REECR算法上改进而来.基于REECR没有考虑簇头在选择时的分布不均匀性,D-REECR将簇头闻的距离作为选择簇头的因素之一,与节点的剩余能量及能量消耗率一起作为选择簇头的依据.这样使各个簇大小基本一致,从而平衡各个节点的能量消耗,达到延长网络生命的目的.仿真结果显示,改进后的D-REECR算法比REECR算法在能量效率上大约提高5%~10%. 相似文献
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Transmission control protocol (TCP) is a reliable transport layer protocol widely used in the Internet over decades. However, the performances of existing TCP congestion control algorithms degrade severely in modern heterogeneous networks with random packet losses, packet reordering and congestion. In this paper, we propose a novel TCP algorithm named TCP-ACC to handle all three challenges mentioned above. It integrates 1) a real-time reorder metric for calculating the probabilities of unnecessary Fast Retransmit (FRetran) and Timeouts (TO), 2) an improved RTT estimation algorithm giving more weights to packets that are sent (as opposed to received) more recently, and 3) an improved congestion control mechanism based on packet loss and reorder rate measurements. Theoretical analysis demonstrates the equilibrium throughput of TCP-ACC is much higher than traditional TCP, while maintaining good fairness with regard to other TCP algorithms in ideal network conditions. Extensive experimental results using both network emulators and real network show that the algorithm achieves significant throughput improvement in heterogeneous networks as compared with other state-of-the-art algorithms. 相似文献
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Christopher S. Taggart Yannis Viniotis Mihail L. Sichitiu 《Performance Evaluation》2009,66(3-5):223-239
Ultra-wideband wireless (UWB) can provide the physical layer for high-throughput personal area networks. When UWB is used for communication between many nodes, relatively long acquisition times are needed when dropping and re-establishing wireless links between the nodes. This paper describes the development and use of mathematical and simulation models to investigate the impact of dropping and reacquiring links between nodes on average packet delay; we also consider the performance of the alternative strategy of forwarding packets through intermediate nodes without breaking the established wireless links. The work presented here assumes that no specific MAC layer protocol, such as WiMedia UWB MAC, is in operation. The paper describes the models, explains the selection of modeling parameters used, compares the average packet delay for a network of three simple UWB nodes and for a ring of ten UWB nodes and explains the use of these results for network design engineers. 相似文献