【作者】 韩慧；

【导师】 王贵竹； 丁旭；

【作者基本信息】 安徽大学 ， 电子与通信工程， 2016， 硕士

【摘要】 移动通信系统通常需要依靠固定的网络基础设施来实现端到端的连接。在一些恶劣的环境中,基站或接入点可能会损坏,无法正常工作,同时基站的覆盖率也达不到无缝连接的要求。通过实现容滞网络DTN (Delay Tolerant Networks)就可以克服或改善这些问题,并能够在这种受限的情况下实现通信连接。在传统网络结构的传输层之上应用层之下引入聚束层(即Bundle层),利用存储—携带—转发机制,可以使DTN在割裂的网络环境中完成通信连接。鉴于一些地区在缺乏通信设施或发生无法预知的地质灾难情况下,网络通信系统可能会瘫痪,本文提出了在容滞网络中实现基于位置服务的构想。用户能够不依赖基站或中继设备,还可以与外界互联,发出求救信号并共享位置信息。本文主要研究内容如下：(1)从DTN网络产生的背景、关键技术以及国内外的研究现状出发,基于Android开发平台,分析研究DTN网络的体系结构,归纳总结了DTN网络的基本特性,及DTN网络在多种平台上的典型应用,深入研究基于Android系统的Bytewalla项目。(2)详细阐述了LBS (Location Based Service,即基于位置的服务)的概念、系统架构及其关键技术,给出了LBS移动开发平台的选择方案。对DTN通信系统在卢Android平台上的程序实现进行研究、分析和设计。重点研究并通过编程实现DTN网络与LBS的结合,主要实现定位功能和好友位置共享功能,能够在移动地图上标注好友的位置,并计算出与好友之间的距离。(3)另外考虑到应用的安全性,还添加了登录注册模块。利用Android系统自带的SQLite数据库实现登录、注册功能,其中SQLite是用C语言编写的轻量级嵌入式数据库引擎。本课题是在目前国内外Android平台下DTN研究的基础上,实现基于位置服务。将DTN、LBS 及 Android系统三者融合在一起,充分发挥了三者的优势,因此,本课题的研究具备一定的现实研究意义和创新意义。更多还原

【Abstract】 Mobile communication systems generally rely on fixed network infrastructure to make sure an end-to-end connection. In some hostile environments, base-stations or access points may be damaged, fail to work properly, while the coverage range cannot meet the requirements for seamless connection either. By implementing DTN, these problems can be overcome or ameliorated quite well and communication connections can be achieved in that limited condition. By introducing a bundle layer between transport layer and application layer and using storage-and-forward mechanism, DTN can work well in intermittent situations.In view of the fact that network communication system may be paralyzed when some areas are in the lack of communication facilities or unpredictable geological disasters occur, this paper proposes the concept of location based service in the delay tolerant network. Users can send out a distress signal and share location information to connect with the external world without base station or relay device. The main research work can be summarized as follows:1. Starting from Delay Tolerant Networks background, key technologies as well as the researching status in domestic and foreign, we analyze and research DTN architecture, summarize the basic characteristics of DTN networks, and DTN applications on multi platforms, as well as analyze the Bytewalla project based on Android system.2. We elaborate the concept, system architecture and key technologies of LBS and give the choice of LBS mobile development platform. Meanwhile, we research, analysis and design the DTN communication system on the Android platform as well as mainly research and realize the combination of DTN network and LBS by programming to achieve positioning function, location sharing, labeling friends’ locations on a moving map, and updating and calculating the distance between friends.3. In addition, taking into account the security of the application, We also add the login and registration module, which is realized by using Android built-in SQLite database. And the SQLite is open source embedded database engine written in C language.This thesis is to realize location based service based on the implementation of DTN in Android system. It takes advantages of them by combining DTN, LBS and Android system together. Therefore, the research of this subject has a certain of practical significance and innovation significance.更多还原