A Systematic Study of IEEE 802.11 DCF Network Optimization From Theory to Testbed
A Systematic Study of IEEE 802.11 DCF Network Optimization From Theory to Testbed
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DOI：
10.1109/access.2020.3018088
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发表时间：
2020-08
期刊：
影响因子：
3.9
通讯作者：
Sohaib Manzoor;Yachao Yin;Yayu Gao;Xiaojun Hei;W. Cheng
中科院分区：
文献类型：
--
作者：
Sohaib Manzoor;Yachao Yin;Yayu Gao;Xiaojun Hei;W. Cheng
在IEEE 802.11无线局域网（WLAN）中，用于介质访问控制（MAC）的重要技术是分布式协调功能（DCF）。DCF提供了两种访问机制，默认的基本访问机制和可选的请求发送/清除发送（RTS/CTS）机制。NS-2仿真器基于统一的分析模型对IEEE 802.11 DCF网络的时延、吞吐量和稳定性进行了预测。NS-3和OMNeT++为IEEE 802.11物理（PHY）层和MAC层建模提供了一个必要的平台，但其准确性尚未得到研究。在这篇文章中，我们提出了两个研究，第一个是比较模拟研究的统一IEEE 802.11 DCF的分析模型，考虑不同的网络条件，各种拓扑结构，不同的接入模式和离散的系统参数NS-3和OMNeT++。建立了基于Linux的实验平台，对数学模型和仿真结果进行了验证。第二是优化研究，以自适应调整RTS阈值，使网络运行在接入模式，转向最大的网络吞吐量性能。通过NS-3和OMNeT++仿真验证了RTS阈值的显式表达式，与以往基于信道估计和数值计算的研究结果形成对比。通过比较仿真、试验台和理论结果，对系统的性能进行了评价。该研究不仅证明了IEEE 802.11 DCF理论模型的可信性，而且保证了NS-3和OMNeT++的结果具有说服力，并为IEEE 802.11无线局域网RTS门限分析提供了基础，可用于实际网络设计考虑。
In IEEE 802.11 wireless local area networks (WLANs), an important technique for medium access control (MAC) is the distributed coordination function (DCF). Two access mechanisms are provided by DCF, the default basic access mechanism and the optional request-to-send/clear-to-send (RTS/CTS) mechanism. The performance of IEEE 802.11 DCF networks has been predicted recently by NS-2 simulator based on a unified analytical model presenting the delay, throughput and stability. NS-3 and OMNeT++ provide an essential platform to model IEEE 802.11 physical (PHY) and MAC layers, nevertheless the accuracy of which is yet not investigated. In this article we present two studies, first is a comparative simulation study of the unified IEEE 802.11 DCF analytical model, by considering distinct network conditions, various topologies, different access modes and discrete system parameters in NS-3 and OMNeT++. A Linux based testbed is setup to validate the mathematical model and the simulation results. The second is the optimization study to adaptively tune the RTS threshold, so that the network operates in an access mode which steers to the maximum network throughput performance. An explicit expression of RTS threshold, verified by the simulations in NS-3 and OMNeT++, is obtained in contrast to previous studies based on channel estimation and numerical calculations. Performance evaluation is done by comparing the simulation, testbed and theoretical results. This study not only proves the credibility of the theoretical model of IEEE 802.11 DCF, but also assures that the results obtained from NS-3 and OMNeT++ are persuasive and provides a foundation for RTS threshold analysis in IEEE 802.11 WLANs for practical network design considerations.