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1.
A multipath source self repair routing (MSSRR) algorithm for mobile ad hoc networks is proposed.By using multiple paths which can be repaired by themselves to transmit packets alternately, the network‘s load is balanced, the link state in the network can be checked in time, the number of the times the route discovery mechanism starts is decreased. If only one route which will be broken can be used to transmit the packets, the route discovery mechanism is restarted. The algorithm is implemented on the basis of dynamic source routing (DSR). The effect of MSSRR on lifetime of the access from the source to the destination and the overhead is discussed. Compared with the performance of DSR, it can be seen that the algorithm can improve the performance of the network obviously and the overhead almost does not increase if the average hop count is larger.  相似文献   

2.
A layered algorithm by bidirectional searching is proposed in this paper to solve the problem that it is difficult and time consuming to reach an optimal solution of the route search with multiple parameter restrictions for good quality of service. Firstly, a set of reachable paths to each intermediate node from the source node and the sink node based on adjacent matrix transformation are calculated respectively. Then a temporal optimal path is selected by adopting the proposed heuristic method according to a non-linear cost function. When the total number of the accumulated nodes by bidirectional searching reaches n-2, the paths from two directions to an intermediate node should be combined and several paths via different nodes from the source node to the sink node can be obtained, then an optimal path in the whole set of paths can be taken as the output route. Some simulation examples are included to show the effectiveness and efficiency of the proposed method. In addition, the proposed algorithm can be implemented with parallel computation and thus, the new algorithm has better performance in time complexity than other algorithms. Mathematical analysis indicates that the maximum complexity in time, based on parallel computation, is the same as the polynomial complexity of O(kn2-3kn+k), and some simulation results are shown to support this analysis.  相似文献   

3.
Privacy is becoming one of the most notable challenges threatening wireless sensor networks (WSNs). Adversaries may use RF (radio frequency) localization techniques to perform hop-by-hop trace back to the source sensor's location. A multiple k-hop clusters based routing strategy (MHCR) is proposed to preserve source-location privacy as well as enhance energy efficiency for WSNs. Owing to the inherent characteristics of intra-cluster data aggregation, each sensor of the interference clusters is able to act as a fake source to confuse the adversary. Moreover, dummy traffic could be filtered efficiently by the cluster heads during the data aggregation, ensuring no energy consumption be burdened in the hotspot of the network. Through careful analysis and calculation on the distribution and the number of interference clusters, energy efficiency is significantly enhanced without reducing the network lifetime. Finally, the security and delay performance of MHCR scheme are theoretically analyzed. Extensive analysis and simulation results demonstrate that MHCR scheme can improve both the location privacy security and energy efficiency markedly, especially in large-scale WSNs.  相似文献   

4.
Since wireless links in Ad hoc networks are more fragile than those in traditional wireless networks due to route flapping, multi-node cooperation plays an important role in ensuring the quality of service (QoS). Based on the authors' previous work, this paper proposes a receiver-controlled multi-node cooperation routing protocol, known as AODV-RCC. In this protocol, nodes form a cooperation group based on signal power. In a cooperation group, signal power between a partner and a transmitter, as well as signal power between the partner and the receiver, must be larger than the signal power between the transmitter and the receiver. Otherwise, the transmission will not benefit from cooperation. To avoid collision or congestion, each cooperation group only contains one partner. This partner offers both data and ACK cooperative retransmission. Its retransmission time should be shorter than the internal retry time of the transmitter' s MAC layer, because it is better for the partner to retransmit firstly, as it offers a more reliable cooperative link. In AODV-RCC, it is the receiver that chooses the partner, because the link between the partner and the receiver is the most important. According to our simulation results, AODV-RCC shortens the end-to-end delay and increases the packet delivery ratio.  相似文献   

5.
Although the encryption of network packets significantly increases privacy, the density of the traffic can still provide useful information to the observer, and maybe results in the breach of confidentiality. In this paper, we address issues related to hiding information in self-similar network, which is proved to be similar with modern communication network. And a statistical hiding algorithm is proposed for traffic padding. The figures and the comparison of Hurst Parameters before and after traffic padding, show the effective performance of the algorithm.  相似文献   

6.
The variable message signs (VMS) have been widely used in guiding and managing the dynamic traffic with development of intelligent transportation technologies. It is known that cell transmission model (CTM) can well reproduce such traffic dynamics as shock waves and jams. This paper presents a new method to estimate the route travel times by using the CTM in conjunction with a logit-based route choice rule. The impacts of VMS on a two-route scenario with recurrent and non-recurrent traffic congestion are numerically investigated by analyzing the changes of route flow and travel time. Simulation results show that in networks with suitable long links, the VMS can positively influence travelers' decision making so as to improve the system performance. For non-recurrent congestion, the value space of the route choice parameter that affects the flow distribution between two routes is narrower in the case of high traffic demand than that in the low demand case.  相似文献   

7.
The stability of the Newton-like algorithm in optimization flow control is considered in this paper. This algorithm is proved to be globally stable under a general network topology by means of Lyapunov stability theory,without considering the round trip time of each source. While the stability of this algorithm with considering the round trip time is analyzed as well. The analysis shows that the algorithm with only one bottleneck link accessed by several sources is also globally stable,and all trajectories described by this algorithm ultimately converge to the equilibrium point.  相似文献   

8.
A novel genetic algorithm with multiple species in dynamic region is proposed,each of which occupies a dynamic region determined by the weight vector of a fuzzy adaptive Hamming neural network. Through learning and classification of genetic individuals in the evolutionary procedure,the neural network distributes multiple species into different regions of the search space. Furthermore,the neural network dynamically expands each search region or establishes new region for good offspring individuals to continuously keep the diversification of the genetic population. As a result,the premature problem inherent in genetic algorithm is alleviated and better tradeoff between the ability of exploration and exploitation can be obtained. The experimental results on the vehicle routing problem with time windows also show the good performance of the proposed genetic algorithm.  相似文献   

9.
Artificial immune systems (AIS) are biologically inspired problem solvers having been successfully applied in many fields. A controller was designed according to the interactive mechanism between immune molecules. Multiform antigens were constructed and corresponding antibodies designed. The concept of “antibiotic” is presented, whose features and injection time as well as construction method discussed. Based on biological immune mechanism, some fuzzy rules are summarized and used in constructing the controller. The result shows that this controller is simple in structure and can be easily computed, so it is suitable for real time control. The control variable can change adaptively according to the error and its change tendency. Therefore the controller is very flexible and can be directly used in controlling some nonlinear plants. To test the validity of the algorithm, two simulation examples are given, one is linear, and the other is nonlinear. The Simulation results indicate that the control performance of this algorithm is better than that of the conventional PID.  相似文献   

10.
To avoid burst contention efficiently,on the basis of feedback-based source flow-rate control(SFC) strategy,a novel fuzzy-control-based assembly algorithm,called dual-fuzzy assembly threshold(DFAT),is proposed in an optical burst switching network.In our algorithm,according to the variations of burst assembly period and the interarrival of burst control packet,the traffic states of edge-switching nodes and core-switching nodes are first obtained.Then,the assembly threshold of bursts is set dynamically in order to operate the source traffic management from the information of traffic states.The performance of DFAT algorithm on burst loss probability is evaluated,and simulation results show that,compared with conventional assembly algorithms,the proposed scheme can constrain the birth of burst contention efficiently,when being a heavy load state of network.  相似文献   

11.
提出了一种适用于混合架构无线Mesh网络的按需路由协议,即MOMDSR(mesh-oriented multipathDSR)。它在DSR(dynamic source routing)协议的基础上,根据Mesh骨干网和客户端域的不同特性,引入路由确认过程,帮助形成Mesh路由器的逐跳路由表,缩短了DSR中数据报文头部所携带的源路由信息,减少了路由开销。同时,它在DSR的路由发现过程中引入了多路径机制。仿真结果表明,MOMDSR协议与DSR协议相比,减少了协议的路由开销,报文传输率有所提高。  相似文献   

12.
在对Ad Hoc网络单路径DSR路由协议分析研究的基础上,提出了一种多路径路由协议MDSR.多路径路由能够提供载荷平衡、容错能力,以及较高的总带宽.应用NS2仿真平台对DSR和MDSR路由协议进行仿真,通过对协议性能指标的比较和分析,得出MDSR协议在路由寻找次数、分组投递率、平均端到端时延和路由开销上优于DSR协议.  相似文献   

13.
DSR协议是一种性能优越的按需路由协议,但是因为节点的移动和连接的破坏使得其缓存中的路由信息容易失效,目前主要的解决方法是:对一个连接或者一条路由设置生存期,通过时间限制机制来解决路由失效问题,但是这种方法还存在问题:生存期不能精确反应网络的拓扑变化.因此引进一种新的方法:通过自适应缓存更新算法来主动传播破坏连接信息到所有保存了该破坏连接的节点中,主动更新缓存.仿真结果表明:自适应缓存更新算法能够快速适应网络拓扑结构的变化,在数据包传输率,传输时延及路由开销方面均优于基于路径缓存和连接缓存的DSR协议.  相似文献   

14.
A new coarse-grained differentiated least interference routing algorithm (CDLI) with DiffServ-Aware was presented. This algorithm is composed of off-line and on-line stages, taking into account both real-time traffic and best-effort traffic. Off-line stage is to determine the shortest path set disjointed path (DP) database for real-time traffic, and to identify link critical value by traffic profile information of real-time traffic and DP database. On-line stage is at first to select route in the DP database for real-time traffic, if there is no path to meet the needs, the dynamic routing will be operated. On-line routing algorithm chooses the relatively short path for real-time traffic to meet their bandwidth requirements, and for best-effort traffic it chooses a lighter load path. The simulation results show that compared with the dynamic online routing algorithm (DORA) and constrained shortest path first (CSPF) algorithm, the new algorithm can significantly improve network throughput and reduce the average path length of real-time traffic. This guarantees quality of service (QoS) of real-time traffic while improving the utilization of network resources.  相似文献   

15.
针对深空通信网络中链路的高时延和间断连通性特征,提出了一种以路径吞吐量最大为准则的路由算法.该算法利用存储转发机制,构建端到端的多条路径;以最大化利用链路的连通时段为目标,依据路径中各链路的连通时序图及链路连通时段的吞吐量,确定链路的最大有效传输时间段,构建端到端多跳最大吞吐量路径.理论分析与仿真结果表明,与传统的路由算法相比,该算法支持非实时连通链路的端到端通信,并得到最大吞吐量的端到端路由.  相似文献   

16.
An ACO-based differentiated integrated routing (ADIR) algorithm is presented for solving the problem of real-time routing. First, the algorithm simplifies the RWA problem into a routing problem with a layered-graph model. Then, we search for routes for the routing problem. The ants used in our algorithm are transported in a control plane, so we can search for routes in the control plane and transport traffic in the data plane synchronously. And the route for a connection request can be determined in real-time. The hops and congestion of routes are also considered in our algorithm, so the blocking probability is reduced. Finally, we use different kinds of ants with the motivation of bandwidth differentiation so that the low bandwidth request traffic can use the key link and the high bandwidth request traffic selects a detour path, and therefore the blocking probability can also be reduced. Simulation results show that ADIR performs better than other routing approaches in terms of traffic blocking probability and traffic blocking fairness.  相似文献   

17.
移动Ad Hoc网络路由协议性能仿真分析   总被引:1,自引:0,他引:1  
介绍了移动Ad Hoc网络(MANET)的路由协议研究现状,使用NS2网络仿真软件对具有代表性的表驱动路由协议DSDV和按需驱动路由协议DSR,AODV进行了仿真数据分析,比较了它们的递交率、端到端延迟、路由长度和能量消耗等性能指标,分析评价了这些路由协议各自的优缺点,提出了设计MANET路由协议的一些建议。  相似文献   

18.
1INTRODUCTION Mobileadhocnetworks(MANET)[1]havebeenreceivedalotofattentionduringthepastfewyearsduetotherapidexpansionofmobiledevicesandthegainedpopularityinmobilecommunica tion.Amobileadhocnetworkisaspecialcaseofmobilenetworks,withoutanyfixedlinkstosup porteachnodeandtoprovideconnectivitytocom municatewitheachother.Eachnodeactsasbothhostandrouteratatimeandperformsalltherout ingsandstatemaintenanceoperations.Thenet worktopologyofamobileadhocnetworkchangesfrequentlyandunpredictablyduetoth…  相似文献   

19.
首先分析了DSR路由协议,然后提出了一种简单易实现的独立多径路由算法.该算法中只有目的节点应答路由请求,中间节点只转发一次路由请求,这样不仅减少了路由分组的数量,而且能为目的节点尽可能提供多条独立路径,减少了目的节点路由计算的复杂度.在NS 2环境下与DSR路由协议在路由开销、丢包率和端到端的平均延时方面进行了对比实验,实验结果表明SIMR算法的性能优于DSR路由协议.  相似文献   

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