异构无线网络中垂直切换算法的评测与改进

Evaluation and Improvement of Vertical Handoff Algorithms in Heterogeneous Wireless Networks

垂直切换作为多网融合的基础,受到了学术界和工业界的广泛关注.目前,相关工作主要集中于垂直切换算法的研究.但由于各种算法用于自身验证的仿真评测环境各不相同,因此无法公平地予以对比.从节点运动模型出发,提出了一组适合垂直切换算法的仿真评价模型.基于所提出的仿真评价模型,对常用的迟滞电平算法和驻留定时器算法进行了性能分析.在此基础上,提出了一种自适应垂直切换算法(self-adaptive vertical handoff algorithm,简称SAVA).仿真实验结果表明,该算法能够有效地提高垂直切换的性能.

Vertical handoff is the basic requirement for convergence of different access technologies and has received tremendous attention from the academia and industry. In recent years, many research works have focused on vertical handoff decision algorithms. However, the evaluation scenarios in different papers are quite different. Thus it is difficult to compare different algorithms in a fair way. This paper analyzes the general motion models of mobile nodes and identifies a set of novel performance evaluation models. Equipped with the models, this paper analyzes the performance of two types of decision algorithms： Hysteresis based algorithm and dwelling-timer based algorithm. Based on the above, a novel vertical handoff decision algorithm, self-adaptive vertical handoff algorithm （SAVA） is presented. Simulations show that SAVA can achieve better performance compared with the conventional methods.