基于GPRS嵌入式温度监测系统设计

介绍了一种在8位单片机系统中实现基于GPRS的Internet接入的设计。本系统终端在单片机里嵌入简化协议栈,在PPP基础上实现小型UDP/IP协议,基于GPRS无线Modem和Internet互连,实现数据收发,能够显示连接过程,具有语音报警功能。数据中心能及时监测终端温度。系统功耗低并且性能稳定,性价比高。重点介绍了终端数据接入Internet详细过程。     

Performance of GSM networks with general packet radio services

Recently, most of the mobile network providers start to introduce general packet radio service (GPRS) in their existing GSM networks. GPRS is the technology that will enable more efficient Internet applications to run on mobile networks even before the installation of 3G systems. However, it is not yet clearly understood, how the new data services will affect the overall network performance. This paper provides a framework for analytical performance evaluation of a single GSM/GPRS cell based on a multidimensional Markov chain model. Important performance measures like new call and handover blocking probabilities, moments of the blocking period distributions, achievable average data rates and resource utilization are determined. Introducing a new connection admission control (CAC) algorithm, different partitioning strategies between GSM and GPRS resources are investigated. Finally, the influence of typical GPRS applications like Internet browsing on traditional GSM services has been studied.     

基于GPRS技术的远程配变监测系统设计

针对配变监测系统对数据传输可靠性和实时性的要求,本文介绍了一种基于移动GPRS无线通信方式的配电变压器电力参数实时监测系统的设计方案。设计了由AT89S52单片机为核心的配电变压器监测装置、GPRS模块(EP120P)和监控中心服务器等组成的监测系统。该系统利用GPRS的无线通信及Internet接入功能,实现了数据的实时采集和传输。实验证明系统具有传输速率快、可靠性高、实时性好、经济实用等优点,可以满足配电监测系统对数据传输的要求。     

基于Android平台的GPRS流量统计系统

GPRS是目前手机上网最主要的数据传输技术之一,因其数据传输速度快而受到了用户的青睐,但是使用费用之高,用户稍不注意就会产生巨额的上网费用.因此对GPRS流量进行实时监控,并能及时通知使用者,这对用户来说十分必要.Android是近年来发展十分迅速的一种基于Linux平台的手机操作系统.通过研究基于Android平台的...     

双网通信模式测控系统的研究与实现

提出一种具有Wi-Fi/GPRS双网模式通信功能的测控系统设计。该系统的网络传输通道既可以是Wi-Fi网络,也可以是GPRS网络,双网模式解决测控设备快速接网时,布线复杂、成本高和可靠性差等问题,为远程通信事业提供便利节约成本。手机监控终端是Android系统智能手机,如果手机使用者有用户的监视密码,则可以监视用户现场的所有模块的实时数据和初始化参数。如果手机使用者有用户的控制密码则可以修改用户现场的参数,实现远方校准,修改模块的工作模式。     

Resource management policies in GPRS systems

In this paper we consider the problem of resource management in GSM/GPRS cellular networks offering not only mobile telephony services, but also data services for the wireless access to the Internet. In particular, we investigate channel allocation policies that can provide a good tradeoff between the QoS guaranteed to voice and data services end users, considering three different alternatives, and developing analytical techniques for the assessment of their relative merits. The first channel allocation policy, voice priority, gives priority to voice in the access to radio channels; we show that this policy cannot provide acceptable performance to data services, since when all the channels are busy with voice connections, data services perceive long intervals of service interruption. The second channel allocation policy is called R-reservation; it statically reserves a fixed number of channels to data services, thus drastically improving their performance, but subtracting resources from voice users, even when these are not needed for data, thus inducing an unnecessary performance degradation for voice services. The third channel allocation policy is called dynamic reservation; as the name implies, it dynamically allocates channels to data when necessary, using the information about the queue length of GPRS data units within the base station. A threshold on the queue length is used in order to decide when channels must be allocated to data. Numerical results show that the dynamic reservation channel allocation policy can provide effective performance tradeoffs for data and voice services, with the additional advantage of being easily managed through the setting of the threshold value.     

基于无线传感器网络的水情监测数据传输的设计

提出一种将基于Zigbee的无线传感器网络应用于水环境检测的系统,该系统将Zigbee网络与GPRS无线通信网络结合,在传感器终端,采用ZigBee无线传输系统,能够将多样化的测量变量进行收集。然后通过ZigBee网络传送到协调器节点,然后协调器节点通过GPRS模块发送,经过GPRS协议与TCP／IP协议转换,完成与Internet的连接,监控中心可以通过Internet网络进行信号的收集,完成数据的远程采集与传输过程。     

OmniCon: a Mobile IP‐based vertical handoff system for wireless LAN and GPRS links

Wi‐Fi based hotspots offer mobile users broadband wireless Internet connectivity in public work spaces and corporate/university campuses. Despite the aggressive deployment of these hotspots in recent years, high‐speed wireless Internet access remains restricted to small geographical areas due to the limited physical coverage of wireless LANs. On the other hand, despite their lower throughput, cellular networks have a significantly wider coverage and are thus much more available. Recognizing that 2.5G or 3G cellular networks can effectively complement wireless LANs, we set out to develop a vertical handoff system that allows mobile users to seamlessly fall back to such cellular networks as the general packet radio service (GPRS) or 3G whenever wireless LAN connectivity is not available. The resulting handoff mechanism allows a network connection of a mobile node to operate over multiple wireless access networks in a way that is transparent to end user applications. In this paper, we present the design, implementation, and evaluation of a fully operational vertical handoff system, called OmniCon, which enables mobile nodes to automatically switch between wireless LAN and GPRS, based on wireless LAN availability, by introducing a simple extension to the existing Mobile IP implementation. We discuss the design issues in the proposed vertical handoff system for heterogeneous networks, including connection setup problems due to network address translation, and the disparity in link characteristics between wireless LANs and GPRS. A detailed performance evaluation study of the OmniCon prototype demonstrates its ability to migrate active network connections between these two wireless technologies with low handoff latency and close to zero packet loss. Copyright © 2006 John Wiley & Sons, Ltd.     

PPP协议链路操作在无线嵌入式终端上的实现

在远程无线实时监控中,基于GPRS网络的无线监控系统成为当前远距离无线监控领域最为广泛的应用。在这种方案中,PPP协议被作为链路控制协议使用。本文主要介绍如何在一个嵌入式终端中利用PPP协议实现与GPRS网络的链路协商,继而使终端能够附着在GPRS网络上,实现数据从无线终端经过GPRS网络最后到达Internet网络的目的。     

基于ARM和GPRS的环境监测系统设计

提出了一种基于GPRS技术的环境监测数据通信系统,此系统主要由监测站、传输网络和监控中心等部分组成,采用GPRS无线网络和Internet网络为通道来实现监测数据的远程传输和状态监控,采用基于ARM的S3C2440A芯片为核心设计的监测站的硬件电路,达到实时监控的目的。     

GPRS在电能质量实时监测系统中的应用

在电能质量实时监测系统中,由于电能质量的数据量大,监测范围广,传统的数据通信方式已满足不了系统实时性的要求。本文提出了基于GPRS的电能质量实时监测数据通信的新方案,该方案利用GPRS的Internet接入功能,在Internet上设置一通信服务器,负责中转主站与GPRS终端设备之间的通信,实现数据的实时采集与传输,应用结果表明该方案的有效性。     

基于GPRS的电力监控终端网络接入方案

针对目前无线通信技术在电力监控系统中的应用,研究了一种通过GPRS网络将电力监控终端接入互联网的技术方案.该方案利用GPRS无线模块与GPRS网络间的无线信道作为物理层接口,在此之上通过PPP协议实现数据链路层,最后采用uIP软件协议栈实现精简的TCP/IP协议作为网络层和传输层.在应用层采用了自定义规约.由于协议各层次都是纯软件实现,因此本方案具有成本低廉、配置灵活的特点,并且在现场使用,效果良好.     

基于GPRS网络的嵌入式无线数据采集系统设计

介绍了GPRS网络的特点及作为数据采集系统中传输单元的连接方法。提出了一种嵌入式数据实时采集无线传输的方法,给出了系统的详细设计。无线数据采集系统采用嵌入式结构,使用32位工业级ARM核心处理器,可以快速采集16路模拟电压信号和32路数字信号,数据转换器分辨率为16位,兼容直流信号和交流信号。无线数据传送部分采用工业级传输模块,通过GPRS网络实时将采集的数据传送到服务器上。     

Modeling and analysis of mobility management state of packet-switched (PS) services in GPRS

There has been an increasing demand for wireless data services due to the popularity of Internet services and circuit-switched (CS) systems are not appropriate for accommodating bursty data traffic. The wireless data services can be efficiently supported in the packet-switched (PS) system and General Packet Radio Service (GPRS) is a representative PS system which is being serviced widely. In GPRS, three mobile station (MS) mobility management states, i.e., idle, ready, and standby are defined in order to accommodate bursty traffic characteristics of data services, and thus, GPRS results in efficient management of radio resources and signaling networks. In order to analyze the performance of GPRS mobility management, we develop an analytical model to derive the steady-state probability of the MS states, which is essential in the performance analysis. The analytical model is validated by using a simulation model. The effect of various input parameters on the steady-state probability and the effect of variances of cell residence time, RA residence time, and packet transmission time are analyzed. Then, location update signaling and paging signaling loads are investigated based on the steady-state probability. Our study provides guideline for proper selection of PS system parameters and can be used to analyze the performance of mobility management schemes for PS systems.     

基于MiniGUI和嵌入式Linux的GSM/GPRS无线通信模块

介绍了GSM／GPRS无线通信模块在以嵌入式Linux和图形用户界面MiniGui为软件平台的设计和实现，提出了一种实用的GSM／GPRS底层驱动程序，使得电话操作和无线上网同时进行。     

基于双阀门值的自适应无缝切换

WLAN和GPRS网络是两种使用最广泛的无线网络技术，两者具有很强的互补性。WLAN能提供较高的数据速率．但只适合热点地区应用。GPRS能提供随时在线的连接，但数据速率较低。假如用户能在两者之间无缝切换，无线数据服务的性能和灵活性将得到极大提高。WLAN／GPRS融合网络可以提供随时随地的无缝接入和移动计算。论文主要基于WLAN网络的可用性、尽可能使用WLAN以达到既高速又廉价的无线接入服务，研究WLAN和GPRS的无缝切换，提出基于双阀门值的自适应无缝切换算法，仿真实验证明这种算法在切换次数和尽可能使用WLAN之间取得较好的平衡。     

基于GPRS的灌区自动化信息管理系统的研究与实现

灌区自动化信息管理系统采用嵌入式技术和GPRS通信技术,采集各闸站的水情和工情参数,实现信息的自动化管理,更好地为水资源调度和管理提供技术支持。闸站采用嵌入式处理器采集河流的水位、雨量和闸门开度等参数,采用GPRS方式通过Intemet发送给信息中心,信息中心将接收到的数据处理后存入服务器的数据库,客户端可通过Intemet浏览各闸站的实时数据和历史数据。经长时间运行表明,系统可靠性高、实时性好,具有广阔的应用前景。     

GPRS数据终端的研究与实现

介绍了GPRS数据终端(简称GPRS DTU)的组成,分析了其实现形式和优缺点。详细地阐述了基于索尼爱立信GR47模块的集成GPRS数据终端的软、硬件实现。测试表明:在服务器的网络速率大于20kb/s时,建立套接字的成功率达到了99.5%。     

基于物联网的智能家居远程控制系统

该文结合了物联网和智能家居的相关技术,将传感器、控制器等设备通过无线技术连接和采集数据信息的处理,实现了使用传感器采集室内温度,光线等数据,在嵌入式终端中进行信息的读取和处理,做出相应的操作。整个过程涉及到基于ZigBee的无线传感网络和GPRS手机通信模块的应用,实现了对家居环境中的光线、温度、烟雾等因素的实时监测,并通过GPRS通信模块和管理系统作出相应的控制,以提升家居环境的安全性、舒适性、便利性。     

基于GPRS的远程监控系统的安全问题研究

简单介绍基于GPRS和Internet的电力监控系统的设计结构,着重分析了影响GPRS系统安全的因素以及系统在运行中所面临的安全威胁,并在此基础上结合GPRS系统的特点,提出了保障系统通信正常及数据传输安全的技术策略。