基于运动趋势的自适应垂直切换算法及其性能评价

A Movement Trend Based Self-Adaptive Vertical Handoff Algorithm and Its Performance Evaluation

采用不同的无线接入技术的多种网络的融合可以提高无线传输性能,为移动用户提供随时随地的网络连接.垂直切换是异构无线网络相互融合的基础.在垂直切换过程中,切换判定是一个非常重要的环节,直接决定切换性能.文中给出了常用的迟滞电平算法和驻留定时器算法中切换判定条件的形式化表达,并对其进行了性能分析.在此基础上,提出了一种自适应的垂直切换算法,通过分析节点的运动趋势,自适应地调节切换触发条件,有效提高垂直切换性能.所涉及的运算均为初等计算,算法简单,适用于低能量、低运算能力的移动设备.仿真实验表明,该算法的综合性能优于迟滞电平算法和驻留定时器算法.

A combination of diverse but complementary wireless access technologies will improve wireless transmission performance and provide mobile users with ubiquitous connectivity. Vertical handoff is the basic requirement for the integration of heterogeneous wireless networks. During the vertical handoff procedure, handoff decision is a crucial issue for an efficient mobility. In this paper, we obtain the mathematical expressions of handoff conditions in traditional hysteresis based and dwelling-timer based handoff algorithms, and analyze their performance. Based on this, we propose a novel vertical handoff decision algorithm, which adaptively adjusts the handoff condition by analyzing the movement trend of mobile hosts and efficiently improves handoff performance. What＇s more, the related computing requirement is very simple to be suitable for mobile devices with limited computing capacity. Simulations show that it can achieve a better integrative handoff performance compared with conventional hysteresis based and dwelling-timer based handoff algorithms.