• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Link Quality Characterization in IEEE 802.11s Wireless Mesh Networks.
【24h】

Link Quality Characterization in IEEE 802.11s Wireless Mesh Networks.

机译：IEEE 802.11s无线网状网络中的链路质量表征。

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

HWMP (Hybrid Wireless Mesh Protocol) has been set as the default routing protocol for the ongoing IEEE 802.11s WMN (Wireless Mesh Network) standard. Unlike most multi-hop routing protocols, which operate at the network layer, HWMP operates at the MAC layer and uses IEEE 802.11s Airtime as a routing metric.;In this dissertation, and in an attempt to delve into the subtleties of this new promising technology, we started first by deploying a real-world pre-IEEE 802.11s indoor WMN testbed that spans two separate buildings, and implements the main traits of this new IEEE standard, e.g., architecture, HWMP, and Airtime. We ascertained the practicality of the testbed by testing real-world traffic such as having Wi-fi enabled stations browsing the Internet, using the deployed WMN as a backhaul. We identified major practical issues and addressed them, e.g., clients association, Inter-networking, and supporting multiple gateways. To encourage the use of real-world WMN testbeds, and to cope with the scarcity of such testbeds, we made the implementation open-source and available online.;IEEE 802.11s Airtime metric depends on the observed loss and transmission rates. However, IEEE 802.11s did not delineate a specific way to measure the loss rate; It is left as an open research issue. To estimate loss rate, most routing metrics, e.g., ETX and ETT, use the broadcast approach whereby broadcast probe frame losses are measured. Such an approach suffers fundamental shortcomings which were addressed by introducing the passive approach. This latter uses data traffic frames instead of broadcast frames. However, the passive approach still suffers from the major shortcoming of probing idle links. In this dissertation, we propose a novel loss rate estimation scheme that overcomes the shortcomings of both broadcast and passive approaches. The proposed scheme estimates losses by tracking their causing events, mainly contention and interference. However, interference measurement remains a challenging task merely because of the impracticality of the current interference models. We propose a novel practical interference measurement framework that adapts the physical interference model and uses a probabilistic model for frame arrivals. A new interference-aware routing metric, ICE ( Interference and Contention Estimator), is shaped and compared to ETX and IEEE 802.11s Airtime routing metrics using a real-world pre-IEEE 802.11s WMN testbed. ICE outperforms both ETX and IEEE 802.11s Airtime with an average of 16%. This outperformance is a significant improvement when taking into account that we were using a single-channel radio approach.;While experimenting with HWMP and Airtime, we noticed a "ping-pong" effect in the behavior of the network. The very few references to this effect in the literature condemn it as a perilous behavior but only superficially address the problem. In this dissertation, we also present a thorough study of the IEEE 802.11s Airtime ping-pong effect, and we highlight its correlation to the underlying rate control algorithms. Using different rate control algorithms (e.g., ARF, AARF, ONOE, AMRR and Constant rate), we prove that transmission rate adaptation is the principal cause behind the effect. We show that the effect is an inherent behavior and not necessarily a perilous one and that an accurate characterization of the effect will improve network performance. We present and discuss a novel research direction consisting of shaping ping-pong-aware mechanisms that, by detecting when a link undergoes such an effect, adapt the network resources for a better performance. In this context, we present a ping-pong-aware mechanism that is O(1), decentralized, and can be easily integrated into the IEEE 802.11s routing protocol. Using extensive ns-3 simulations, we show that the new mechanism has an average outperformance of 5%. This latter is a slight improvement; However, it remains as a proof of concept for future research in the direction of shaping better ping-pong-aware mechanisms.
机译：HWMP（混合无线网格协议）已设置为正在进行的IEEE 802.11s WMN（无线网格网络）标准的默认路由协议。与大多数在网络层运行的多跳路由协议不同，HWMP在MAC层运行，并使用IEEE 802.11s Airtime作为路由度量标准；本论文并试图探究这种新的有希望的微妙之处在技​​术上，我们首先通过部署一个现实世界的IEEE 802.11s之前的室内WMN测试平台，该测试平台跨越两座单独的建筑物，并实现该新IEEE标准的主要特征，例如，架构，HWMP和Airtime。我们通过测试实际流量来确定测试台的实用性，例如使用已部署的WMN作为回程，通过启用Wi-fi的站点浏览Internet。我们确定了主要的实际问题并解决了这些问题，例如客户关联，网络间连接以及支持多个网关。为了鼓励使用现实世界中的WMN测试平台，并应对此类测试平台的不足，我们将实现开源并在线提供。IEEE 802.11s空中时间指标取决于观察到的损耗和传输速率。但是，IEEE 802.11s并未描述测量丢失率的特定方法。它留待研究。为了估计丢失率，大多数路由度量，例如ETX和ETT，使用广播方法，由此测量广播探针帧丢失。这种方法存在一些基本缺陷，这些缺陷可以通过引入被动方法来解决。后者使用数据业务帧而不是广播帧。然而，被动方法仍然遭受探测空闲链路的主要缺点。本文提出了一种新颖的丢失率估计方案，该方案克服了广播和被动方法的缺点。提议的方案通过跟踪造成损失的事件（主要是竞争和干扰）来估计损失。但是，仅由于当前干扰模型的不实用性，干扰测量仍然是一项艰巨的任务。我们提出了一种新颖的实用干扰测量框架，该框架适用于物理干扰模型，并针对帧到达使用了概率模型。使用实际的IEEE 802.11s之前的WMN测试平台，对新的可感知干扰的路由度量标准ICE（干扰和争用估计器）进行了比较，并将其与ETX和IEEE 802.11s空中时间路由度量标准进行比较。 ICE的平均性能比ETX和IEEE 802.11s Airtime高出16％。考虑到我们使用的是单通道无线电方法，这种出色的性能是一项显着的改进。在尝试HWMP和Airtime的同时，我们注意到网络行为的“乒乓”效应。文献中很少提及这种效应，谴责它是一种危险的行为，但只是表面上解决了这个问题。在本文中，我们还对IEEE 802.11s空中时间乒乓效应进行了深入研究，并重点介绍了其与底层速率控制算法的相关性。使用不同的速率控制算法（例如ARF，AARF，ONOE，AMRR和恒定速率），我们证明了传输速率自适应是造成这种影响的主要原因。我们表明，这种影响是一种固有行为，而不一定是一种危险行为，并且对这种影响的准确表征将改善网络性能。我们提出并讨论了一种新颖的研究方向，该研究方向包括塑造乒乓感知机制，该机制可以通过检测链路何时受到这种影响来适应网络资源以实现更好的性能。在这种情况下，我们提出了一种O（1），分散式且可以轻松集成到IEEE 802.11s路由协议中的乒乓感知机制。使用大量的ns-3仿真，我们证明了新机制的平均性能为5％。后者稍有改善；但是，它仍然是未来研究在构筑更好的乒乓感知机制方面的概念证明。

著录项

  • 作者

    Abid, Mohamed Riduan.;

  • 作者单位

    Auburn University.;

  • 授予单位 Auburn University.;
  • 学科 Engineering Computer.;Computer Science.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 105 p.
  • 总页数 105
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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