共查询到20条相似文献,搜索用时 31 毫秒
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移动Ad hoc网络中基于链路稳定性预测的按需路由协议 总被引:4,自引:0,他引:4
移动Ad hoc网络拓扑的高度动态变化是造成传统按需路由协议的路由频繁通断的主要原因,因此在传统按需路由协议的基础上进行链路稳定性预测扩展,增强路由稳定性具有十分重要的意义。该文利用分组的接收功率把节点间的相对运动划分为靠近和远离两种类型,然后在不同相对运动类型下根据节点间距离得到了的链路平均维持时间。在路由过程中,中间节点利用得到的链路平均维持时间设置请求报文的转发延迟,通过一定转发规则选择稳定性较强的链路构成路径。仿真结果表明进行链路稳定性预测扩展后的按需路由协议能够有效增强路由的稳定性,并提高网络性能。 相似文献
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提出一种网络编码感知机会路由算法,将COPE协议中的机会监听和网络编码技术引入现有的机会路由机制,采用新的路由度量即LQM(链路质量度量)标准来选择备选转发节点集,在确保选择路径的编码机会的同时也在一定程度上保证了链路质量。仿真结果表明,此方法能提高网络的整体吞吐量,增加编码机会,降低平均端到端的时延。 相似文献
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钱景辉 《微电子学与计算机》2013,30(1):5-7,12
在分析现有机会网络转发策略及机会网络中节点的运动特性的基础上,通过改进节点的转发策略提出一种新的机会网络路由算法(Delayed Spray and Wait,DSW).算法假设的应用场景为节点均沿着预先存在的路径移动,通过延迟发送转发数据包,可以显著减少网络中的低效数据包转发的数量.仿真结果表明,在合适的应用场景下该算法可以显著的降低网络中数据包的转发数量并略微提高传输成功率,这对于减少节点能耗和改善网络拥塞状况都具有实际意义. 相似文献
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一种贪婪地理路由协议的改进算法 总被引:1,自引:0,他引:1
《现代电子技术》2016,(11):16-20
贪婪转发策略广泛应用于无线传感网络(WSNs)的地理路由协议中,但是,该协议存在数据包丢失严重以及在遭遇路由空洞时路由效率低下的不足。为此,提出一种贪婪地理路由协议的改进算法,记为GPSR-I算法。GPSR-I算法在选择下一跳转发节点时,利用节点离目的节点距离、方向以及节点密度信息计算度量值,然后依据该度量值决策下一跳转发节点。仿真数据表明,与GPSR相比,GPSR-I算法能够有效降低平均端到端传输时延、路由开销,并提高了数据包传输率。 相似文献
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AODV协议是目前比较成熟的应用于移动自组网(MANET)中的一种反应式路由协议,其缺点主要是协议开销比较大,运动情况下路由优化性能不理想。利用为RREQ消息设置时限和为中间节点根据自身队长设置回复RREP消息延迟的方法,提出了一种改进的AODV协议(AODV-DL),有效地提高了网络的投包率和路由优化性能,降低了网络的协议开销。提出了将路由优化性能作为协议的一项新的评价标准。描述了其实现策略,并给出了NS2下的仿真结果。 相似文献
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随着网络负载增加,经典的TPGF( Two-Phase geographic Greedy Forwarding)算法难以找到节点分离路径,会导致网络吞吐量、投递率以及端到端时延性能下降。此外,当网络拓扑变动不大时, TPGF中每条路径所包含节点要消耗比其他节点更多的能量,会导致其过快死亡,从而影响网络性能。为此,将联合网络编码技术引入 TPGF,提出一种编码与能量感知的 TPGF 路由算法( NE-TPGF)。该算法综合考虑节点的地理位置、编码机会、剩余能量等因素,同时利用联合网络编码技术进一步扩展编码结构,充分利用网络编码优势来建立相对最优的传输路径。仿真结果表明, NE-TPGF能够增加编码机会,提高网络吞吐量和投递率,降低端到端时延,并且还有利于减少和平衡节点的能量消耗。 相似文献
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无线传感器网络中节点大多采用电池供电,让节点以低能耗将采集的数据传递到信宿,对无线传感器网络有效运行极为重要.该文提出了能量有效的可靠机会路由EROR(Energy-efficient Reliable Opportunistic Routing),它利用结合节点剩余能量和链路上收发双方的总能耗的转发代价,选择转发节点集合(简称“转发集”)、主转发节点和协助转发节点,让节点调节发射功率并利用随机线性编码把数据包分片编码发送到转发集,进而以多跳方式把数据可靠低能耗地传递到信宿.仿真结果表明:在网络生存时间和能耗方面,EROR比已有路由策略CodePower更优. 相似文献
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Daisuke Umehara Satoshi Denno Masahiro Morikura Takatoshi Sugiyama 《Ad hoc Networks》2011,9(2):164-179
Deployment of wireless relay nodes can enhance system capacity, extend wireless service coverage, and reduce energy consumption in wireless networks. Network coding enables us to mix two or more packets into a single coded packet at relay nodes and improve performances in wireless relay networks. In this paper, we succeed in developing analytical models of the throughput and delay on slotted ALOHA (S-ALOHA) and S-ALOHA with network coding (S-ALOHA/NC) for single-relay multi-user wireless networks with bidirectional data flows. The analytical models involve effects of queue saturation and unsaturation at the relay node. The throughput and delay for each user node can be extracted from the total throughput and delay by using the analytical models. One can formulate various optimization problems on traffic control in order to maximize the throughput, minimize the delay, or achieve fairness of the throughput or the delay. In particular, we clarify that the total throughput is enhanced in the S-ALOHA/NC protocol on condition that the transmission probability at the relay node is set at the value on the boundary between queue saturation and unsaturation. Our analysis provides achievable regions in throughput on two directional data flows at the relay node for both the S-ALOHA and S-ALOHA/NC protocols. As a result, we show that the achievable region in throughput can be enhanced by using network coding and traffic control. 相似文献
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Chi Zhang Xiaoyan Zhu Yuguang Fang 《Selected Areas in Communications, IEEE Journal on》2009,27(5):662-672
This paper investigates the problem of how much benefit network coding can contribute to the network performance in terms of throughput, delay, and storage requirements for mobile ad hoc networks (MANETs), compared to when only replication, storage and forwarding are allowed in relay nodes. We characterize the throughput-delay-storage tradeoffs under different node mobility patterns, i.e., i.i.d. and random walk mobility, with and without network coding. Our results show that when random linear coding instead of replication is used in MANETs, an order improvement on the scaling laws of MANETs can be achieved. Note that previous work showed that network coding could only provide constant improvement on the throughput of static wireless networks. Our work thus differentiates MANETs from static wireless networks by the role network coding plays. 相似文献
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Aiming at the problem that the location distribution of cluster head nodes filtered by wireless sensor network clustering routing protocol was unbalanced and the data transmission path of forwarding nodes was unreasonable,which would increase the energy consumption of nodes and shorten the network life cycle,a clustering routing protocol based on improved particle swarm optimization algorithm was proposed.In the process of cluster head election,a new fitness function was established by defining the energy factor and position equalization factor of the node,the better candidate cluster head node was evaluated and selected,the position update speed of the candidate cluster head nodes was adjusted by the optimized update learning factor,the local search and speeded up the convergence of the global search was expanded.According to the distance between the forwarding node and the base station,the single-hop or multi-hop transmission mode was adopted,and a multi-hop method was designed based on the minimum spanning tree to select an optimal multi-hop path for the data transmission of the forwarding node.Simulation results show that the clustering routing protocol based on improved particle swarm optimization algorithm can elect cluster head nodes and forwarding nodes with more balanced energy and location,which shortened the communication distance of the network.The energy consumption of nodes is lower and more balanced,effectively extending the network life cycle. 相似文献
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We introduced the use of two-hop forwarding to increase the throughput of an 802.11 network in our earlier work (Narayanan
et al., Proceedings of IEEE WCNC’05, March 2005). Other researchers have also considered the benefits of forwarding in the 802.11 infrastructure mode to increase
the total network throughput. But the high-data rate node that forwards data for other nodes will have to spend its energy
transmitting this data. Previous work on forwarding implicitly assumed that in an enterprise network, the collective good
is sufficient to justify this increased energy expense. However, it is important to address the advantages and the cost of
participating in such schemes from the individual forwarding node’s perspective. Since a node cannot know whether there are
other high-data rate nodes in the network capable and willing to forward data, it needs to assume that it is the only node
with the capability to do so. In this paper, we focus our analysis on the cost benefit for such a forwarding node. We quantify
the throughput improvement, medium access delay reduction and energy consumption for the forwarding node in a saturated network.
The analysis and simulation results demonstrate that in a saturated network, participation in forwarding provides the high-data
rate node with significant benefits in throughput and media-access-delay, while increasing the number of bits-per-joule even
if it is the only node participating in data forwarding as suggested in this paper. The increase in the bits-per-joule is
due to the reduction in the total amount of time needed by the high data rate node to transmit a given number of its own application bits. This results in savings in energy expenditure for the forwarding node. Based on these benefits, we conclude
that it is unequivocally in the interest of a high data rate node to participate in two-hop forwarding schemes in 802.11 networks. 相似文献
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Since wireless sensor networks are emerging as innovative technologies for realizing a variety of functions through a number of compact sensor nodes, security must be justified and ensured prior to their deployment. An adversary may compromise sensor nodes, forcing them to generate undesired data, and propagation of these data packets through the network results in wasteful energy consumption. We develop a security mechanism to detect energy-consuming useless packets, assuming that a sensor node is able to generate multiple message authentication codes (MAC) using preshared secrets. The forwarding nodes along the path verify the validity of the packet by checking the authenticity of the attached MACs. This mechanism performs well when a malicious node does not have all the cryptographic keys. However, packets, generated by the malicious node having all the keys, would be considered as legitimate, and thus, the forwarding nodes become unable to detect and discard them. To deal with this problem, we devise another mechanism in which each forwarding node is capable of checking such suspicious nodes. We have quantified the security strength through analysis and simulations to show that the proposed mechanisms make the entire network energy conserving. 相似文献
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网络编码方法能有效提高数据传输效率,但采用该方法的机会网络数据转发机制均未考虑传输中的编码数据迭代冗余副本控制问题。为了充分降低译码复杂度并减少迭代冗余副本,提出了相遇持续时间估计及编码机会感知方法,进而设计了带有传输容量估计的编码冗余控制数据转发机制。节点以分布式的方式感知数据编码机会,为不同扩散程度的数据确定相应的优先级,并根据传输容量估计结果完成转发控制,以充分利用节点间的相遇持续时间。结果表明,所提出机制有效地减少了网络中的冗余副本,使译码所需的数据量趋于理论上的最小值,改善了网络资源利用率。 相似文献
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王冬梅 《太赫兹科学与电子信息学报》2021,19(5):934-938
由于水下传感网络的高时延、低带宽和高能耗等特性,建立路由协议仍存在挑战。为此,提出基于拓扑感知的水下传感网络路由(TAR)。TAR路由先通过交互Beacon包,使每个节点获取网络拓扑信息,并建立邻居信息表。再依据节点剩余能量和链路的可靠性,择优选择下一跳转发节点,进而提高路由的稳定性,平衡节点间能耗。仿真结果表明,提出的TAR路由增强了路由稳定性,并减少了节点的能耗。 相似文献