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1.
In the last fewyears there has been quite anin-terest in the ad hoc(self-organizing)networks basedon code division multiple access(CDMA)tech-niques[1].Thefocus of this paperisto work on powercontrol algorithms for ad hoc CDMA networks.As-suming that thereis a receive node that receivendif-ferent signals transmitted fromnneighbor transmitnodes throughnchannels that are assigned in oneti me slot and using different spread codes.In order to meet signal-to-interference-ratio(SIR)requirement,th… 相似文献
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Rejab Hajlaoui Eesa Alsolami Tarek Moulahi Herv Guyennet 《International Journal of Communication Systems》2019,32(12)
Recently, the routing problem in vehicular ad hoc networks is one of the most vital research. Despite the variety of the proposed approaches and the development of communications technologies, the routing problem in VANET suffers from the high speed of vehicles and the repetitive failures in communications. In this paper, we adjusted the well‐known K‐medoids clustering algorithm to improve the network stability and to increase the lifetime of all established links. First, the number of clusters and the initial cluster heads will not be selected randomly as usual, but based on mathematical formula considering the environment size and the available transmission ranges. Then the assignment of nodes to clusters in both k‐medoids phases will be carried out according to several metrics including direction, relative speed, and proximity. To the best of our knowledge, our proposed model is the first that introduces the new metric named “node disconnection frequency.” This metric prevents nodes with volatile and suspicious behavior to be elected as a new CH. This screening ensures that the new CH retains its property as long as possible and thus increases the network stability. Empirical results confirm that in addition to the convergence speed that characterizes our adjusted K‐medoids clustering algorithm (AKCA), the proposed model achieves more stability and robustness when compared with most recent approaches designed for the same objective. 相似文献
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This paper proposes an address configuration scheme for a MANET. In this paper, the tree-based architecture and the algorithm of constructing a MANET are presented. In this architecture, a proxy node can assign a unique address for neighbor new nodes, so the address configuration task is distributed around all proxy nodes. The transmission of control packets is controlled within one-hop scope, so the cost is reduced and the delay is shortened. Through this architecture, the address resources released by failed nodes can be automatically reclaimed for reuse, so a proxy node has always the sufficient address space for assignment. In order to ensure the uniqueness of a node’s address, the paper also proposes the MANET merging and partitioning algorithms. Finally, this paper evaluates the performance metrics of both the proposed scheme and the existing schemes, and the results show that the proposed scheme reduces the address configuration cost and shortens the address configuration delay. 相似文献
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针对Ad Hoc网络路由发现过程中广播路由请求分组导致的广播风暴问题,提出了一种基于节点度估计和静态博弈转发策略的Ad Hoc网络路由协议NGRP.NGRP考虑边界影响,采用分段函数的思想将网络场景分为中心、边和角区域,分别估算网络中节点在不同区域的节点度,避免了周期性广播Hello消息获取节点度导致的开销;NGRP路由请求分组的转发采用静态博弈转发策略,利用节点度估算参与转发路由请求分组的节点数量,将转发和不转发作为策略集合,设计效益函数,通过纳什均衡获得节点转发路由请求分组的转发概率,从而减少了路由请求分组广播过程中产生的大量的冗余、竞争和冲突,提高了路由发现过程中路由请求分组的广播效率.运用NS-2对协议的性能进行大量的仿真,结果表明:NGRP的分组投递率、路由开销、MAC层路由开销和吞吐率这4项指标明显优于AODV+FDG,AODV with Hello和AODV without Hello协议. 相似文献
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Composite service provision in mobile ad hoc networks encounters great challenges and its success rate is not satisfactory because the nodes' locations are dynamic and the nodes maybe unavailable at any time.Composite service is built through the service composition.In mobile ad hoc networks,the factors influencing the success rate of service composition are mainly the number of nodes and the time spent for the composition.The node's failure probability is proportional to the length of time the node exist in the networks.In order to improve the success rate of service composition,we take several measures.First,we split the service requirement into several segments and cluster the nodes,so that the nodes' waiting time for service composition can be reduced.Second,we propose a new node model of "one node contains multiple services" in mobile ad hoc networks.Using this type of nodes model,the number of nodes required for service composition can be reduced.These means can increase the success rate of service composition. 相似文献
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Supporting formal and informal meetings with digital information and ubiquitous software systems every day becomes increasingly mandatory. These meetings require that the integration of devices participating in the meeting and the information flow among them should be done as seamless as possible to avoid jeopardizing the natural interactions among participants. Trying to contribute to address such a challenge, this article presents a framework that allows devices integration and smooth information flow. This framework, named Clairvoyance, particularly integrates mobile computing devices and large-screen TVs through a mobile ad hoc network, and thus it eases the implementation of shared displays intended to be used in formal and informal meetings. Clairvoyance provides a set of services through an API, which can be used to develop ubiquitous applications that support meetings in particular scenarios. The preliminary evaluation of this framework considered its usage to implement a ubiquitous system that supports social meetings among friends or relatives. According to developers, the framework is easy to use and it provided all required services for such an application. The solution obtained was then utilized by end-users in simulated meetings. The evaluation results indicate that the Clairvoyance services were suitable to support the informal meetings, and that the devices integration and information flow were transparent for the end-users. 相似文献
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应用NS-2技术进行网络仿真和协议算法研究,已广泛成为国内外学者和工程技术人员的首要选择。由于在NS-2网络仿真与模拟技术应用中常常对系统进行修改、移动和增减,相继产生的系统平台正确性与完整性问题也得到更多重视。重点对NS-2仿真系统Test Suite测试组件的应用进行研究,并以一个无线局域网测试组件为实例,较为全面地介绍Test Suite组件的测试原理、实现方法以及测试过程,希望对读者应用NS-2仿真系统Test Suite测试组件以及编写新的测试组件提供帮助。 相似文献
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动态交通信息系统是智能交通系统中重要的组成部分,作为一种新兴的车辆间无线通信网络技术,车载自组网可有效提高高速行驶车辆间的信息共享能力。文章阐述利用基于车载自组网的交通信息采集和交通事件协同检测算法、大规模海量交通信息的分布式组织和实日寸处理方法、基于位置的交通信息分发协议等技术,构建一个动态交通信息系统,实现改进交通信息系统中的事件检测的准确性和实时性,提高大规模交通信息处理的实时性,改善交通信息分发的针对性。 相似文献