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Mobile low-duty-cycle wireless sensor network is a new kind of wireless multi-hop network,which is self-organized by a large number of nodes that have mobile ability and are able to get into sleep for a long time.Such networks have wide application prospects in national defense,industry,agriculture and other fields that need long term monitoring in severe environments.However,the movement and the sleeping features of nodes lead to constantly change of network topology,which makes the nodes difficult to discover their neighbors quickly.Therefore,the nodes cannot achieve optimal distribution decisions.In order to solve this problem,a new proactive neighbor discovery algorithm was proposed.This algorithm made the nodes in the network take the initiative to find their neighbors when they woke up,and avoided the delay caused by long time waiting in the traditional passive neighbor discovery.In addition,by predicting the movement speed and distance of neighbors,the neighbor set at the next moment can be quickly determined,which can further reduce the delay and obtain more accurate neighbor discovery results.Theoretical analysis and experimental results show that compared with the existing algorithms,the algorithm can find all the neighbors in MLDC-WSN with less energy consumption and lower delay. 相似文献
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Mobile low-duty-cycle wireless sensor network (MLDC-WSN) are a kind of new ad hoc networks that are appeared in recent years.In MLDC-WSN,the nodes only have limited storage spaces.Moreover,the nodes would move or sleep from time to time.Therefore,these networks have some problems such as connectivity is hard to be maintained and data are hard to be transmitted to their destinations for storage in time.As a result,data persistence (i.e.,the probability that all data can be recovered after some nodes die in the networks) is low.A distributed algorithm named LT-MDS for improving data persistence in MLDC-WSN was proposed.The algorithm used a new infectious data dissemination method to transmit the data,which enabled the data to be received by almost all the mobile nodes in a network with low latency and improved the reliability of the network.When a node receives the data,it would use LT (Luby transform) codes to encode and save them.By this way,the nodes with limited storage spaces can save more data information.Theoretical analyses and simulations show that LT-MDS can complete the process of data dissemination and preservation with low latency,and it can achieve high data persistence. 相似文献
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We consider the problem of determining, in a distributed, asynchronous and scalable manner, what nodes are “neighbors” in a wireless network. Neighbor discovery is an important enabler of network connectivity and energy conservation. An asynchronous, probabilistic neighbor discovery algorithm is presented that permits each node in the network to develop a list of its neighbors, which may be incomplete. The algorithm is analyzed and parameter settings are derived which maximize the fraction of neighbors discovered in a fixed running time. A companion distributed algorithm is also described which allows all the nodes in the network to execute that neighbor discovery algorithm without the need to agree on a common start time. 相似文献
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节点定位是传感网络最基本的技术之一,对此提出一种基于移动信标的网格扫描定位算法(Mobile Beacon Grid-Scan,MBGS)。该算法在网格扫描定位算法基础上,利用一个移动信标巡航整个传感区域,产生大量的虚拟信标,提高网络信标覆盖率,然后普通节点利用这些信标信息减小其可能区域(Estimative Rectangle,ER),并把新可能区域网格坐标质心作为其最新估计坐标。仿真结果表明,与Bounding Box、质心定位算法以及传统的网格扫描定位算法相比,MBGS定位方法的定位精度更高,算法性能更加稳定。 相似文献
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低占空比(low duty cycle,LDC)无线传感器网络邻居发现算法是当前无线传感器网络领域的研究热点之一。当前LDC无线传感器网络的邻居发现算法大致可分为同步邻居发现算法和异步邻居发现算法,其中异步发现算法又可分为基于法定人数的调度算法（Grid quorum和 U-connect）和基于中国剩余定理的调度方法(Disco算法)。针对发现延迟和能量消耗,通过仿真实验对当前LDC无线传感器网络邻居发现领域里的典型算法进行了对比分析,在此基础上得出LDC无线传感器网络邻居发现算法新的研究方向。 相似文献
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嵌套移动网络在扩大通信范围的同时会带来严重的路由优化问题。针对已有优化方案在可部署性和性能等方面的不足提出了一种新的嵌套移动网络路由优化方案（NMNRO）,通过扩展邻居发现协议,在嵌套移动网络内通告相同的外地前缀,并更新接入路由器的邻居缓存和移动路由器的路由表,然后通过向对端发送绑定更新来实现路由优化。性能分析表明,该方案为嵌套移动网络提供了较为完整的路由优化方案,在降低优化开销的同时,具有较好的可部署性和兼容性。仿真实验结果表明该方案具有较低的切换时延和较高的有效吞吐量,且这些性能优势会随嵌套层数的增加而更加明显。 相似文献
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视频传感器网络VSN（Video Sensor Network）相对于传统的传感器网络需要更高的带宽和更低的延时。文中提出了一种适合于VSN的多径路由算法MPTT（Multi-path Predicted Transmission Time）。这种路由算法是从MAC层建模,根据链路邻居节点的流量信息来估算出路径的整体延时,再根据每条路径延时的大小分配数据流量使其总体的延时达到最小。经过仿真可以得出,在数据流量不大时,该算法与延时最小的路径延时相当。随着所分配流量的加大,MPTT比DSR延时要小,而且可以提供更高的数据流带宽。 相似文献
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采用定向天线的MANET邻居发现算法研究 总被引：4，自引：0，他引：4
在无线多跳移动自组织网(MANET)中采用定向天线(特别是波束成形天线)有一系列优点。这一技术能增加单跳传输的距离、减小干扰、提高空间复用度,从而能显著增大系统容量。然而,适应于采用全向天线的传统MANET的媒质接入控制(MAC)、功率控制、邻居发现、路由等方法必须作相应的修改。在分析前人相关研究的基础上,针对MANET使用定向天线情况下的邻居发现机制及算法进行了深入研究,提出了2种采用定向天线的MANET的邻居发现算法———非辅助TD模式的定向邻居发现算法与非辅助TRD模式的定向邻居发现算法。这2种算法与目前已提出的其他定向邻居发现算法的最大区别是,它们不需要依赖GPS或其他辅助信息就能独立实现邻居发现。 相似文献
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针对邻居发现或路由发现阶段可能受到虫洞攻击的问题,提出了一种约束防御机制SenLeash,通过限制消息传输的距离来防御虫洞攻击。SenLeash依赖2个因子：每个节点到初始基站的距离和一个精选的接收距离阈值。基于接收信号强度RSSI,提出了一种nRSSI测量方法,在网络初始化阶段用来测量每个节点到初始基站的距离。基于每个节点的接收概率和MAC层的最大重传次数,对接收距离阈值的选择方法进行了研究。实验结果表明,SenLeash可有效减少由虫洞攻击导致的虚假邻居节点个数和无效回复消息个数。 相似文献
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In low-duty-cycle wireless sensor networks, designers have to cope with unreliable links and limited communication capacity. In this work, we propose COST, a coding scheme that leverages spatial-temporal diversity to achieve higher energy efficiency and lower delay of packet transmissions. We particularly address long sleeping intervals in low-duty-cycle networks by exploiting multi-path diversity. Specifically, we propose to employ an erasure-coding scheme to improve reliability. With respect to energy efficiency and delivery timeliness, we formulate the problem in optimal allocation of coded blocks over multiple paths, which is then proved to be NP-hard. We further propose a near-optimal algorithm to solve the allocation problem. Through extensive simulations, we evaluate the impact of network parameters and demonstrate the effectiveness of our proposal. 相似文献
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分层移动IPv6快速切换在一定程度上减少了切换延时，但切换过程中由网络层移动检测和使用重复地址检测（DAD）配置一个新转交地址引起的延时对实时业务仍然有很大的影响。为了减轻这些影响，文中提出了一种更加有效的快速邻居发现和DAD机制，减小了切换延时，提高了网络的性能。 相似文献
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With recent advances in wireless networking and in low‐power sensor technology, wireless sensor networks (WSNs) have taken significant roles in various applications. Whereas some WSNs only require minimal bandwidth, newer applications operate with a noticeably larger amount of data. One way to deal with these applications is to maximize the available capacity by utilizing multiple wireless channels. We propose DynaChannAl, a distributed dynamic wireless channel allocation algorithm that effectively distributes nodes to multiple wireless channels in WSNs. Specifically, DynaChannAl targets applications where mobile nodes connect to preexisting wireless backbones and takes the expected end‐to‐end queuing delay as its core metric. We used the link quality indicator values provided by 802.15.4 radios to whitelist high‐quality links and evaluate these links with the aggregated queuing latency, making it useful for applications that require minimal end‐to‐end delay (i.e., health care). DynaChannAl is a lightweight and adoptable scheme that can be incorporated easily with predeveloped systems. As the first study to consider end‐to‐end latency as the core metric for channel allocation in WSNs, we evaluate DynaChannAl on a 45 node test bed and show that DynaChannAl successfully distributes source nodes to different channels and enables them to select channels and links that minimizes the end‐to‐end latency. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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＂互动式＂邻区优化方法根据用户在时间轴上的通话规律,采用多次通话前后互动式分析,以用户通话异常释放为切入点,结合当前邻区配置等多种信息,进行邻区优化,可全面提升邻区优化的准确性。 相似文献
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在Ad hoc网络中邻居节点发现（Neighbor Discovery）是网络初始化中的重要步骤之一,节点邻居的信息对于几乎所有的链路选择和路由算法都有着重要的影响,特别是在采用方向性天线时邻居发现不仅难度更大而且其影响作用也更明显。通过分析在采用方向性天线时的Ad hoc网络中的邻居发现算法,总结出了其一般步骤,即首先通过判断网络规模来进行天线收发模式选择算法和扫描图案的选择,然后再设计相应的通信握手协议。 相似文献
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为了提高小消息、大并发、高吞吐量、高实时消息传输的高效性和可靠性,提出了一种基于UDP（User Datagram Protocol,用户数据报协议）的电子政务消息传输的新技术.该技术采用了一种消息刚好满足使用（Just meet）的思想,通过可靠UDP技术、低延迟处理协议等信息处理技术,尽量剔除数据传输中没有用的多余信息,来保证信息传输处理的低延迟和可靠性.应用结果表明,该技术提高了消息传输效率和可靠性,消息的处理能力可以高达每秒百万（条）级,处理延迟可控制在50ms左右. 相似文献