基于GPRS数据传输智能终端的实现

介绍了利用单片机控制GPRS调制解调器模块实现GSM网络GPRS业务数据接入的智能终端系统,详细介绍了系统的硬件电路实现、单片机与GPRS模块的接口方式,以及嵌入式TCP/IP协议在本系统中的应用和实现。     

基于GPRS的远程无线透传终端系统的设计与实现

介绍了利用单片机控制GPRS调制解调器模块实现GSM网络GPRS业务数据接入的智能终端系统，详细介绍了系统的功能实现、终端与控制中心的通信流程、以及系统的软件实现。     

基于单片机远程水位检测系统的研究

设计了一种基于单片机的远程水位监测系统,该系统包括水位采集电路、继电器控制水泵加水模块、液晶显示、报警电路、GPRS通信模块等构成.光电传感器将水位信息送入单片机进行处理,通过键盘设置液位高、低和限定值,保持水位稳定在设定的阈值范围内.若水位高度超出液位的上下限阈值时,则及时发出报警并经通信电路模块进行GPRS输送数据到上位机端进行处理.仿真实验证明该控制能够直观地显示水位高度,方便的控制水位高度.     

基于Zigbee和GPRS的远程水质监控系统

为了满足远程水质监控的需求,设计了一种基于Zigbee和GPRS的远程水质监控系统。该系统采用CC2530模块构建无线水质数据采集网络,通过双串口单片机STC12C5A60S2实现数据汇聚和对GPRS模块的控制,利用GPRS模块接入Internet,通过TCP/IP协议将水质数据发送到数据管理中心,实现对水质的远程监控。实验结果表明,该系统组网简单,系统稳定性高,成本较低,达到了设计要求,有广阔的应用市场。     

基于GPRS短信模块的远程数据控制系统

本文设计了一种基于GPRS短信模块的远程控制系统．从而达到对一些野外或异地终端进行控制。该系统由上、下位机组成,上位机又由GPRS短信模块和PC机组成．两者之间通过串口．使用AT指令进行通信。上位机用户界面采用C”Builder软件设计。下位机由GPRS短信模块、51单片机终端系统组成。上位机可以随时读取下位机的工作参数．对系统的工作状态进行控制。该方案进一步促进了工业控制系统的智能化和信息化。     

微控制器基于GPRS无线上网的实现

提出了一种基于通用分组无线业务(General Packet Radio Service,GPRS)技术的微控制器无线上网解决方案,介绍了嵌入式系统硬件设计的基本组成,给出了GPRS模块无线上网的具体流程,实现了微控制器和控制中心的传输控制协议(Transmission Control Protocol,TCP)连接,最后指出了该方案的应用前景。     

基于GPRS短信模块的远程数据控制系统

设计了一种基于GPRS短信模块的远程控制系统,借助移动通信网的GPRS网络,采用短信息模式进行通信,从而达到对一些野外或异地终端进行控制。该系统由上、下位机组成,上位机又由GPRS短信模块和PC机组成,两者之间通过串口使用AT指令进行通信。上位机用户界面采用C＋＋Builder软件设计。下位机由GPRS短信模块和51单片机终端系统组成。上位机可以随时读取下位机的工作参数,根据当前参数,用户可以对系统的工作状态进行控制。该方案进一步促进了工业控制系统的智能化和信息化。     

无线通信的远程监控系统设计

随着移动通信技术的快速发展,具有远程无线控制功能的监控系统得到广泛应用。设计了一种基于GPRS通信网络的远程监控系统,详细介绍了系统的硬件结构及软件设计。该系统采用单片机通过串口连接GPRS通信模块和图像捕获模块,并扩展红外探测模块,在接收到来自于远程控制中心或红外模块探测的控制指令后启动图像捕获模块,并将所拍摄的图像自动传至指定手机,实现对现场的实时监控。该系统成本低廉,稳定性好,是一种高性价比的远程监控解决方案。     

基于GPRS和Internet的河流水情实时远程监测系统研究

为实现河流水位信息的实时远程监控,提出基于GPRS和Internet的河流水情实时远程监测系统解决方案。以STC12C5A60S2单片机作为系统控制中心,控制水位传感器进行河流水位信息的采集和处理,并控制GPRS通信模块进行数据传输。选用LC-SW1型水位传感器测量水位,使用SIM900A无线通信模块作为GPRS通信模块。监控通信网络通过具有公网IP的服务器建立,网络连接方式为TCP,将远程监测端的数据和监控端连接。该系统具有成本低和监控范围广的优点,能够满足应用的要求。     

基于GPRS的除尘器远程监控系统

设计并实现了一种基于GPRS模块MC55和51单片机的远程监控系统。分别介绍了上位机和下位机的组成及实现方法,详细说明了系统的硬件和软件两方面的设计方式。重点解决了该系统中的数据采集、GPRS无线传输以及监控中心模块的设计。以GPRS为基础的无线数据应用为实现远距离的数据传输和监控提供了一种新的技术手段。该系统大大地提高了现场环境监控的工作效率以及信息的准确性。     

基于Q2400系列模块的无线数据传输设计

Q2400系列模块是Wavecom公司生产的基于GPRS/GSM(通用分组无线电业务/全球移动通信系统)网络的无线数据传输模块,工作于900(850)MHz/1800(1900)MHz,使用高性能GPRSClass 10提供完整的2.5G(第2.5代)GPRS/GSM语音和数据容量.文中介绍了模块的功能和调试手段,给出了基于模块的无线数据传输系统的设计方法.由于技术难度最大的高频电路部分和射频部分都在无线模块内部处理,无疑大大减小了硬件的开发难度.     

双频立体无线覆盖网络的构建

本文主要介绍利用"双频小区交叉覆盖"和"上倾小区高层覆盖"两种创新覆盖模式来构建立体覆盖双频网络,并与传统覆盖模式进行优缺点比较,探讨在中小城市构建双频立体覆盖网络新的建设思路.     

GSM 900/1800双频系统及其组网考虑

本文介绍了ＧＳＭ９００／１８００双频系统的基本特点和系统性能、初步分析，讨论了ＧＳＭ９００／１８００双频系统的组网方案以及需注意的问题。     

A novel power-amplifier module for quad-band wireless handset applications

This paper presents a novel power-amplifier module (PAM) designed for GSM850-, GSM900 MHz, DCS1800- and PCS1900-MHz handset applications. The module combines an InGaP HBT power-amplifier integrated circuit, two integrated couplers, a dual-band logarithmic RF power detector/controller, and some additional passive components. The logarithmic RF power detector was implemented in the module to accomplish linear-in-decibel output power dependency. This allows the handset manufacturers to calibrate output power (Pout) at one or two points, with error as low as +/-0.3 dB, thus reducing test time in mass production. Due to higher accuracy, our novel design significantly reduces the power consumption during normal operation. Our design is the first to include two integrated directional couplers in a handset RF PAM. It significantly improves power control accuracy over load variations. In this paper, we show that the directivity of the integrated couplers is critical for establishing accurate power control over phase variations at high values of load mismatch. In addition, the presented module features fully integrated impedance matching at input and output ports with DC blocks. The entire module is plastic encapsulated on a 10 mm /spl times/ 10 mm laminate substrate. The module offers higher accuracy of Pout control, smaller size, lower bill-of-materials, and a shorter Pout calibration time to handset manufacturers. It is a very desirable RF PAM to handset designers because of its unique features. Under a low single supply voltage of 3.2 V, the PAM provides 35-dBm output power, 55% power-added efficiency (PAE) in the GSM900 band, and 33 dBm and 50% PAE in the DCS1800 band.     

Design of an LTCC tri-band transceiver module for GPRS mobile applications

This paper presents the design and results of a low-temperature co-fired ceramic (LTCC) module for tri-band general packet radio service (GPRS) mobile applications. The proposed transceiver module integrates the tri-band (EGSM900/DCS1800/PCS1900) antenna switch, the surface-acoustic-wave filters for band selection, and a fully integrated tri-band transceiver integrated circuit into one LTCC package. By taking advantages of the three-dimensional layout capability of the LTCC substrate, the embedded circuit elements can be arranged vertically for size reduction. In addition, the utilization of mutual coupling leads to a novel design of miniature lumped-element realization of the transmission line. By combining these miniature passive component designs, the proposed module features a compact size of 13.8 mm /spl times/ 8.1 mm, with a packaged height of 1.8 mm. The module is compliant with the European Telecommunications Standards Institute regulations for GPRS mobile applications and is currently in use in commercially available mobile phones.     

GSM900／1800M双频网建设及与3G网络协调发展

分析GSM900M／1800M频率资源,探讨了900M网络可承载的话务容量负荷,双频网的建设门限、组网方式分析、双频网建设策略以及2G／3G网络协调发展等。     

Teletraffic performance of GSM900/DCS1800 in street microcells

Studies the teletraffic issues of the Global System of Mobile Communications at 900 MHz (GSM900), and its sister, the Digital Communication System at 1800 MHz (DCS1800). The teletraffic simulations have the essential elements of GSM900 and DCS1800, but they are not be exact simulations of these two systems. The approach is to site microcellular base stations, using the microcellular prediction tool MIDAS, into a fictitious city and into parts of two real cities. The radio coverage plots are then imported into a teletraffic simulator TELSIM. The simulator is loaded with the basic GSM900 and DCS1800 parameters to give an indication of the teletraffic performance of these systems in the three environments     

Implementation of PCNs using DCS 1800

The digital cellular system (1800 MHz) (DCS 1800), a standard for personal communication networks (PCNs) that has been developed by the European Telecommunications Standards Institution (ETSI), is discussed. The GSM 900-MHz cellular standard, from which DCS 1800 is derived, is reviewed. GSM/DCS 1800 network interfaces and signaling, implementation of PCNs using DCS 1800, PCN cellular design, PCN transmission networks, and the services and functionality of DCS 1800 are described     

A 3.2-V operation single-chip dual-band AlGaAs/GaAs HBT MMIC poweramplifier with active feedback circuit technique

This paper describes the design and experimental results for a 3.2-V operation single-chip AlGaAs/GaAs heterojunction bipolar transistor (HBT) monolithic microwave integrated circuit (IMMIC) power amplifier for GSM900 and DCS1800 dual-band applications. The following two new circuit techniques are proposed for implementing the power amplifier. One is an on-chip HBT bias switch which in turn switches the amplifier between 900 and 1800 MHz. The proposed switch configuration allows the switch using a high turn-on voltage of 1.3 V of AlGaAs/GaAs HBT's to operate with a 3-V low supply voltage, because the switch circuitry needs no stacked configuration. The other is an active feedback circuit (AFB) to prevent permanent failure of HBT's in the output power stage even under severe conditions of oversupply voltage and strongly mismatching load. Experimental results revealed that the proposed feedback circuit, which works as a voltage limiter, can protect the output stage HBT's from an excessive collector voltage swing even when the amplifier is operated under a condition of a 5-V oversupply voltage and a 10:1 voltage standing-wave ratio (VSWR) mismatching load. Under a normal condition of 3.2 V and a 50-Ω matching load, the IC is capable of delivering an output power of 34.5 dBm and a power-added efficiency (PaE) of 52% in a GSM900 mode, and a 32-dBm output power and a 32% PAE in a DCS1800 mode     

International intercomparison of specific absorption rates in a flat absorbing phantom in the near-field of dipole antennas

This paper reports the results of an international intercomparison of the specific absorption rates (SARs) measured in a flat-bottomed container (flat phantom), filled with human head tissue simulant fluid, placed in the near-field of custom-built dipole antennas operating at 900 and 1800 MHz, respectively. These tests of the reliability of experimental SAR measurements have been conducted as part of a verification of the ways in which wireless phones are tested and certified for compliance with safety standards. The measurements are made using small electric-field probes scanned in the simulant fluid in the phantom to record the spatial SAR distribution. The intercomparison involved a standard flat phantom, antennas, power meters, and RF components being circulated among 15 different governmental and industrial laboratories. At the conclusion of each laboratory's measurements, the following results were communicated to the coordinators: Spatial SAR scans at 900 and 1800 MHz and 1 and 10 g maximum spatial SAR averages for cubic volumes at 900 and 1800 MHz. The overall results, given as mean standard deviation, are the following: at 900 MHz, 1 g average 7.850.76; 10 g average 5.160.45; at 1800 MHz, 1 g average 18.44/spl plusmn/1.65; 10 g average 10.14/spl plusmn/0.85, all measured in units of watt per kilogram, per watt of radiated power.