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Towards the quality of service for VoIP traffic in IEEE 802.11 wireless networks.

机译：迈向IEEE 802.11无线网络中VoIP流量的服务质量。

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摘要

The usage of voice over IP (VoIP) traffic in IEEE 802.11 wireless networks is expected to increase in the near future due to widely deployed 802.11 wireless networks and VoIP services on fixed lines. However, the quality of service (QoS) of VoIP traffic in wireless networks is still unsatisfactory. In this thesis, I identify several sources for the QoS problems of VoIP traffic in IEEE 802.11 wireless networks and propose solutions for these problems.;The QoS problems discussed can be divided into three categories, namely, user mobility, VoIP capacity, and call admission control. User mobility causes network disruptions during handoffs. In order to reduce the handoff time between Access Points (APs), I propose a new handoff algorithm, Selective Scanning and Caching, which finds available APs by scanning a minimum number of channels and furthermore allows clients to perform handoffs without scanning, by caching AP information. I also describe a new architecture for the client and server side for seamless IP layer handoffs, which are caused when mobile clients change the subnet due to layer 2 handoffs.;I also present two methods to improve VoIP capacity for 802.11 networks, Adaptive Priority Control (APC) and Dynamic Point Coordination Function (DPCF). APC is a new packet scheduling algorithm at the AP and improves the capacity by balancing the uplink and downlink delay of VoIP traffic, and DPCF uses a polling based protocol and minimizes the bandwidth wasted from unnecessary polling, using a dynamic polling list. Additionally, I estimated the capacity for VoIP traffic in IEEE 802.11 wireless networks via theoretical analysis, simulations, and experiments in a wireless test-bed and show how to avoid mistakes in the measurements and comparisons.;Finally, to protect the QoS for existing VoIP calls while maximizing the channel utilization, I propose a novel admission control algorithm called QP-CAT (Queue size Prediction using Computation of Additional Transmission), which accurately predicts the impact of new voice calls by virtually transmitting virtual new VoIP traffic.
机译：由于广泛部署的802.11无线网络和固定线路上的VoIP服务，预计在不久的将来IEEE 802.11无线网络中IP语音（VoIP）流量的使用将增加。但是，无线网络中VoIP流量的服务质量（QoS）仍然不令人满意。本文主要针对IEEE 802.11无线网络中VoIP流量的QoS问题找出几种来源，并提出解决方案。讨论的QoS问题可分为用户移动性，VoIP容量和呼叫接纳三类。控制。用户移动性会在切换过程中导致网络中断。为了减少接入点（AP）之间的切换时间，我提出了一种新的切换算法，即选择性扫描和缓存，该算法通过扫描最少数量的信道来找到可用的AP，并且还允许客户端通过缓存AP来执行不扫描的切换信息。我还描述了用于无缝IP层切换的，用于客户端和服务器端的新体系结构，这是当移动客户端由于第2层切换而改变子网时引起的。我还提出了两种方法来提高802.11网络的VoIP容量：自适应优先级控制（APC）和动态点协调功能（DPCF）。 APC是一种新的AP数据包调度算法，它通过平衡VoIP流量的上下行延迟来提高容量，而DPCF使用基于轮询的协议，并使用动态轮询列表将不必要的轮询所浪费的带宽最小化。此外，我通过在无线测试台中进行理论分析，仿真和实验，估计了IEEE 802.11无线网络中VoIP流量的容量，并展示了如何避免测量和比较中的错误。最后，保护现有VoIP的QoS在最大程度地利用信道的同时，我提出了一种新颖的准入控制算法QP-CAT（使用附加传输计算的队列大小预测），该算法通过虚拟传输虚拟的新VoIP流量来准确预测新语音呼叫的影响。

著录项

  • 作者

    Shin, Sangho.;

  • 作者单位

    Columbia University.;

  • 授予单位 Columbia University.;
  • 学科 Computer Science.
  • 学位 Ph.D.
  • 年度 2008
  • 页码 213 p.
  • 总页数 213
  • 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

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