• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Forwarding in mobile opportunistic networks.
【24h】

Forwarding in mobile opportunistic networks.

机译：在移动机会网络中转发。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Recent advances in processor speeds, mobile communications and battery life have enabled computers to evolve from completely wired to completely mobile. In the most extreme case, all nodes are mobile and communication takes place at available opportunities---using both traditional communication infrastructure as well as the mobility of intermediate nodes. These are mobile opportunistic networks.;Data communication in such networks is a difficult problem, because of the dynamic underlying topology, the scarcity of network resources and the lack of global information. Establishing end-to-end routes in such networks is usually not feasible. Instead a store-and-carry forwarding paradigm is better suited for such networks. This dissertation describes and analyzes algorithms for forwarding of messages in such networks.;In order to design effective forwarding algorithms for mobile opportunistic networks, we start by first building an understanding of the set of all paths between nodes, which represent the available opportunities for any forwarding algorithm. Relying on real measurements, we enumerate paths between nodes and uncover what we refer to as the path explosion effect. The term path explosion refers to the fact that the number of paths between a randomly selected pair of nodes increases exponentially with time. We draw from the theory of epidemics to model and explain the path explosion effect. This is the first contribution of the thesis, and is a key observation that underlies subsequent results.;Our second contribution is the study of forwarding algorithms. For this, we rely on trace driven simulations of different algorithms that span a range of design dimensions. We compare the performance (success rate and average delay) of these algorithms. We make the surprising observation that most algorithms we consider have roughly similar performance. We explain this result in light of the path explosion phenomenon.;While the performance of most algorithms we studied was roughly the same, these algorithms differed in terms of cost. This prompted us to focus on designing algorithms with the explicit intent of reducing costs. For this, we cast the problem of forwarding as an optimal stopping problem. Our third main contribution is the design of strategies based on optimal stopping principles which we refer to as Delegation schemes. Our analysis shows that using a delegation scheme reduces cost over naive forwarding by a factor of O( N ), where N is the number of nodes in the network. We further validate this result on real traces, where the cost reduction observed is even greater.;Our results so far include a key assumption, which is unbounded buffers on nodes. Next, we relax this assumption, so that the problem shifts to one of prioritization of messages for transmission and dropping. Our fourth contribution is the study of message prioritization schemes, combined with forwarding. Our main result is that one achieves higher performance by assigning higher priorities to young messages in the network. We again interpret this result in light of the path explosion effect.
机译：处理器速度，移动通信和电池寿命的最新发展使计算机能够从完全有线发展为完全移动。在最极端的情况下，所有节点都是移动的，并且通信在可能的情况下进行-使用传统的通信基础结构以及中间节点的移动性。这些是移动机会网络。由于动态底层拓扑，网络资源稀缺和缺乏全球信息，在这样的网络中进行数据通信是一个难题。在这样的网络中建立端到端路由通常是不可行的。取而代之的是，存储转发范例更适合于此类网络。本文描述并分析了此类网络中消息转发的算法。为了设计用于移动机会网络的有效转发算法，我们首先要建立对节点之间所有路径的集合的理解，这代表了任何机会的可用机会。转发算法。依靠实际的测量，我们枚举了节点之间的路径，并揭示了我们所谓的路径爆炸效应。术语“路径爆炸”是指以下事实：随机选择的一对节点之间的路径数随时间呈指数增长。我们从流行病学理论出发，对路径爆炸效应进行建模和解释。这是本文的第一篇论文，也是后续研究结果的关键观察。我们的第二篇论文是对转发算法的研究。为此，我们依赖跨越设计尺寸范围的不同算法的跟踪驱动模拟。我们比较了这些算法的性能（成功率和平均延迟）。我们做出令人惊讶的观察，即我们认为的大多数算法具有大致相似的性能。我们根据路径爆炸现象来解释此结果。虽然我们研究的大多数算法的性能大致相同，但这些算法在成本方面有所不同。这促使我们专注于设计算法，其明确意图是降低成本。为此，我们将转发问题视为最佳停止问题。我们的第三个主要贡献是基于最佳停止原则的策略设计，我们将其称为授权方案。我们的分析表明，使用委派方案比朴素转发可将成本降低O（N）倍，其中N是网络中的节点数。我们进一步在真实的轨迹上验证了此结果，其中观察到的成本降低幅度更大。到目前为止，我们的结果包括一个关键假设，即节点上的无限制缓冲区。接下来，我们放宽此假设，以便问题转移到消息优先传输和丢弃的优先级之一。我们的第四个贡献是研究消息优先级排序方案，并结合转发。我们的主要结果是通过为网络中的年轻消息分配更高的优先级来实现更高的性能。我们根据路径爆炸效应再次解释此结果。

著录项

  • 作者

    Erramilli, Vijay.;

  • 作者单位

    Boston University.;

  • 授予单位 Boston University.;
  • 学科 Computer Science.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 134 p.
  • 总页数 134
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 自动化技术、计算机技术;
  • 关键词

  • 入库时间 2022-08-17 11:38:30

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号