无线异构网络定位技术和切换决策算法研究

发布时间：2018-05-23 11:07

本文选题：无线异构网络 + LTE/Wi-Fi　；参考：《南京邮电大学》2017年硕士论文

【摘要】：随着移动互联网的发展和智能终端的快速增长,移动数据业务正呈现爆炸性的增长势头。为了满足这一需求,高密度、高覆盖率的异构网络开始问世。异构网络的部署带来了利益如:提高网络的吞吐量和资源利用率,分担了Maccrcell的数据业务,扩展了小区的覆盖范围等;同时也带来挑战,如频繁切换问题,小区间干扰问题等。本论文基于无线异构网络的定位技术和切换决策算法研究的具体工作如下:(1)概述了课题的研究背景与研究现状:介绍异构网络的相关概念,常用的无线定位技术和无线定位技术性能的评估指标等;无线异构网络切换决策算法等相关技术。(2)针对新一代核心LTE网络下传统定位技术存在两个问题:第一个是在NLOS环境下定位精度不高;第二是对定位的基站数量有要求。为了解决传统定位技术在NLOS环境下定位精度不高的问题,本文针对在异构网络LTE/Wi-Fi下提出一种改进的单基站混合定位算法,基于信号传输的几何模型和信号强度衰落模型,建立目标函数,利用改进的基于适应度动态调节惯性权重的PSO算法求解。仿真结果表明,该改建算法充分利用NLOS环境信息,模型简单、定位精度高,稳定性好。(3)切换随UE的移动频繁发生,切换的次数直接影响系统性能和网络的QoS。本文基于LTE/LTE-A异构网络对现有的切换决策算法研究,发现有两个问题需要改进:第一是当前切换算法中的大多数缺乏考虑Femtocell中的共层切换,第二个问题是在UE快速进入快速离开问题的情况下如何切换。为了解决这两个问题,基于LTE/LTE-A提出一种改进的高效切换决策算法。它是一种基于UE速度的新型切换决策算法。在该算法中,根据UE速度和所处目标小区的一个时间阈值限制切换。仿真结果表明,改进的切换决策算法的与传统切换决策算法相比,切换次数显著减少,网络系统性能有所提高。
[Abstract]:With the development of mobile Internet and the rapid growth of intelligent terminals, mobile data services are showing explosive growth momentum. In order to meet this demand, high density, high coverage of heterogeneous networks began to come out. The deployment of heterogeneous networks brings benefits such as improving network throughput and resource utilization sharing the data services of Maccrcell and extending the coverage of the cell. At the same time it also brings challenges such as frequent handoff problem inter-cell interference problem and so on. In this paper, based on the location technology of wireless heterogeneous network and the research work of handoff decision algorithm, as follows: 1) summarize the research background and research status: introduce the related concepts of heterogeneous network, Commonly used wireless positioning technology and wireless positioning technology performance evaluation index; There are two problems in the traditional localization technology in the new generation of core LTE networks: the first is that the positioning accuracy is not high in the NLOS environment, and the second is the requirement of the number of the base stations located in the new generation of core LTE networks. In order to solve the problem of low accuracy of traditional positioning technology in NLOS environment, this paper proposes an improved hybrid location algorithm for single base station under heterogeneous network LTE/Wi-Fi, which is based on geometric model of signal transmission and signal intensity fading model. The objective function is established and solved by the improved PSO algorithm which dynamically adjusts inertial weight based on fitness. The simulation results show that the proposed algorithm makes full use of the NLOS environment information, the model is simple, the location accuracy is high, and the stability is good. The frequency of handover occurs frequently with the movement of UE, and the number of handoffs directly affects the performance of the system and the QoS of the network. In this paper, we study the existing handoff decision algorithms based on LTE/LTE-A heterogeneous networks, and find that there are two problems to be improved: first, most of the current handoff algorithms lack of common layer handoff in Femtocell. The second question is how to switch when UE quickly enters a quick exit problem. In order to solve these two problems, an improved efficient handoff decision algorithm based on LTE/LTE-A is proposed. It is a new switching decision algorithm based on UE speed. In this algorithm, switching is limited by UE speed and a time threshold of the target cell. The simulation results show that compared with the traditional handoff decision algorithm, the improved handoff decision algorithm has significantly reduced the number of handoff and improved the performance of the network system.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.5;TN92

【参考文献】