Performance Analysis and Optimization of Handoff Algorithms in Heterogeneous Wireless Networks
Performance Analysis and Optimization of Handoff Algorithms in Heterogeneous Wireless Networks
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DOI：
10.1109/tmc.2007.70768
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发表时间：
2008-07
影响因子：
7.9
通讯作者：
Min Liu;Zhongcheng Li;Xiao-Bing Guo;E. Dutkiewicz
中科院分区：
文献类型：
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作者：
Min Liu;Zhongcheng Li;Xiao-Bing Guo;E. Dutkiewicz
在异质无线网络中，切换可以分为水平切换和垂直切换。当移动节点跨越不同链路层技术的无线接入网络时，VHO在实现无缝数据传输方面起着重要作用。目前的VHO算法主要集中在何时触发VHO，而忽略了如何综合考虑当前所有可用的网络(同构或异质)，从所有可用候选中选择HHO或VHO的最优网络。在本文中，我们提出了一个评估VHO算法的分析框架。随后，我们扩展了传统的基于滞后和基于驻留定时器的算法，使其同时支持VHO和HHO决策，并将它们应用于复杂的异质无线环境。我们将这些增强算法分别称为E-HY和E-DW。基于提出的分析模型，给出了E-HY和E-DW中切换条件的形式化定义，并对它们的性能进行了分析。随后，我们提出了一种新的通用切换判决算法GHO，用于在异类无线网络中触发HHO和VHO。分析表明，与E-HY和E-DW相比，GHO具有更好的性能。仿真结果验证了分析结果，并验证了GHO在匹配率、TCP吞吐量和UDP吞吐量方面均优于传统算法。
In heterogeneous wireless networks, handoff can be separated into two parts: horizontal handoff (HHO) and vertical handoff (VHO). VHO plays an important role to fulfill seamless data transfer when mobile nodes cross wireless access networks with different link layer technologies. Current VHO algorithms mainly focus on when to trigger VHO, but neglect the problem of how to synthetically consider all currently available networks (homogeneous or heterogeneous) and choose the optimal network for HHO or VHO from all the available candidates. In this paper, we present an analytical framework to evaluate VHO algorithms. Subsequently, we extend the traditional hysteresis based and dwelling-timer based algorithms to support both VHO and HHO decisions and apply them to complex heterogeneous wireless environments. We refer to these enhanced algorithms as E-HY and E-DW, respectively. Based on the proposed analytical model, we provide a formalization definition of the handoff conditions in E-HY and E-DW and analyze their performance. Subsequently, we propose a novel general handoff decision algorithm, GHO, to trigger HHO and VHO in heterogeneous wireless networks. Analysis shows that GHO can achieve better performance than E-HY and E-DW. Simulations validate the analytical results and verify that GHO outperforms traditional algorithms in terms of the matching ratio, TCP throughput and UDP throughput.