【正文】 路交換系統(tǒng)，而GPRS是一種分組交換系統(tǒng)?？旖莸卿汫PRS的用戶一開機(jī)，就始終附著在GPRS網(wǎng)絡(luò)上，每次使用時只需一個激活的過程，一般只需1~3秒的時間馬上就能登錄至互聯(lián)網(wǎng)，而固定撥號方式接入互聯(lián)網(wǎng)需要撥號、驗(yàn)證用戶名密碼、登錄服務(wù)器等過程，至少需要8~10秒甚至更長的時間。中國移動的GPRS服務(wù)將首先為高端商務(wù)人士和追求時尚、喜歡新技術(shù)的年輕新人類提供各種移動商務(wù)咨詢、移動辦公與移動娛樂等服務(wù)。例如，當(dāng)4個用戶同時上網(wǎng)時，就必須占用4個數(shù)據(jù)信道。系統(tǒng)通信不忿采用TCP協(xié)議，各數(shù)據(jù)終端通過GPRS數(shù)字傳輸模塊與服務(wù)器建立連接，用戶終端提供列表和圖形等多種數(shù)據(jù)顯示方式，獨(dú)立的通信服務(wù)器和數(shù)據(jù)庫服務(wù)器則為系統(tǒng)提供了足夠的伸縮度。核心設(shè)計在于單片機(jī)與CTM900C的連接和軟件的編寫。 自動電量平衡分析178。它由主機(jī)、鍵盤、顯示器等組成?，F(xiàn)在有些工廠的技術(shù)人員或其它業(yè)余電子開發(fā)者搞出來的某些產(chǎn)品，不是電路太復(fù)雜，就是功能太簡單且極易被仿制。只有在單片機(jī)（Microcontroller）出現(xiàn)后，計算機(jī)才真正 地從科學(xué)的神圣殿堂走入尋常百姓家，成為廣大工程技術(shù)人員現(xiàn)代 化技術(shù)革新，技術(shù)革命的有利武器。小到家用電器儀器儀表，大到機(jī)器設(shè)備和整套生產(chǎn)線都可用單片機(jī)來實(shí)現(xiàn)自動化控制。各種各樣的接入技術(shù)被運(yùn)用于無線網(wǎng)絡(luò)。在互聯(lián)網(wǎng)上的信息包傳輸全部基于IP協(xié)議。主程序吧這些程序塊有機(jī)的結(jié)合到一起，相互控制。這樣，模塊與Internet傳輸數(shù)據(jù)時，報文就會顯示。 uchar TC35_RE[500]。 //進(jìn)行PPP撥號// uchar GPRS_IP_DNS_CMD[]={AT%ETCPIP?}。 void delayX(uchar m) { uchar k,h。 // 使能USART0的發(fā)送和接受 UCTL0 |= CHAR。 // 使能USART0的接收中斷 }void send_uart( uchar a_s) { while (!(IFG1 amp。 send_uart(0X0A)。)。)。 TC35_CON=GPRS_APN_flag。,39。 for(i=0。isizeof(GPRS_TCP1)1。,39。,39。}void GPRS_Init(void) { long int i,m。(TC35_RE[8]==39。(TC35_RE[40]==39。(TC35_RE[62]==39。)) GPRS_TCPIP()。//初始化完成 for(i=0。} send_uart(0X22)。//分號 send_uart(0X0D)。i500。//回車send_uart(0X0A)。i500。= ~OFIFG。 _EINT()。 }}pragma vector = UART0RX_VECTOR__interrupt void data_Receive(void) // UART接收中斷{ i_receive=RXBUF0?；贕PRS的系統(tǒng)也有一定的缺點(diǎn)，例如，現(xiàn)在的GPRS網(wǎng)還不夠穩(wěn)定，有丟包的現(xiàn)象；主控制器要實(shí)現(xiàn)IP協(xié)議，使用起來比較復(fù)雜；上位機(jī)基于互聯(lián)網(wǎng)的解決方案保密性較差等。 參考文獻(xiàn)[1] 周靜. MSC1210的GPRS無線通信系統(tǒng)設(shè)計[D]. 武漢大學(xué), 2010.[2] 百度文庫. 使用單片機(jī)實(shí)現(xiàn)GPRS通信系統(tǒng)的設(shè)計.[3] 蔣延彪. 單片機(jī)原理及應(yīng)用[M].重慶:重慶大學(xué)出版社，2005[4] 何立民. 單片機(jī)高級教程應(yīng)用于設(shè)計[M]. 北京:北航空航天大學(xué)出版社, 1999.[5] 林伸茂. 8051單片機(jī)徹底研究基礎(chǔ)篇[M]. 北京:人民郵電出版社, 2004.[6] 北京應(yīng)嘉興業(yè)科技介紹.[7] [8] [9] Bonner. InSitu Modbus Communication Protocol .2007[10] SIMCOM. SIM300 [11] Hardware Specfication 2006[12] GPS Receiver Familiy Designer Guide. 1999[13] 256Kb Bytewide FRAM Memory[14] , Information System for the EffectiveManagement of [15] Gregory JPEG Still Picture Compression Standard [J].IEEETransactions on Consumer Electronics, :26~27[16] YuWei Huang, Embedded Remote Power Mangement,Sensors for Industry :105[17] 的無線DDN ,2005(5): 23附錄A 英文原文 Research Report General packet radio service (GPRS) is a service available to users of GSM mobile phones of a mobile data. It provides moderate speed data transfer, by using unused TDMA channels in the GSM network. Originally there was some thought to extend GPRS to cover other standards, but instead those networks are being converted to use the GSM standard, so that is the only kind of network where GPRS is in use. GPRS is integrated into GSM standards releases starting with Release 97 and onwards. First it was standardised by ETSI but now that effort has been handed onto the 3GPP.GPRS basicsGPRS is different from the older Circuit Switched Data (or CSD) connection included in GSM standards releases before Release 97 (from 1997, the year the standard was feature frozen). In CSD, a data connection establishes a circuit, and reserves the full bandwidth of that circuit during the lifetime of the connection. GPRS is packetswitched which means that multiple users share the same transmission channel, only transmitting when they have data to send. This means that the total available bandwidth can be immediately dedicated to those users who are actually sending at any given moment, providing higher utilisation where users only send or receive data intermittently. Web browsing, receiving s as they arrive and instant messaging are examples of uses that require intermittent data transfers, which benefit from sharing the available bandwidth. Figure 1 GPRS network structure.Usually, GPRS data are billed per kilobytes of information transceiver while circuitswitched data connections are billed per second. The latter is to reflect the fact that even during times when no data are being transferred, the bandwidth is unavailable to other potential users.GPRS originally supported (in theory) IP, PPP and connections. The latter has been typically used for applications like wireless payment terminals although it has been removed as a requirement from the standard. can still be supported over PPP, or even over IP, but doing this requires either a router to do encapsulation or intelligence built into the end terminal. Figure 2 GPRS network poseGPRS speeds and profilePacketswitched data under GPRS is achieved by allocating unused cell bandwidth to transmit data. As dedicated voice (or data) channels are setup by phones, the bandwidth available for packet switched data shrinks. A consequence of this is that packet switched data has a poor bit rate in busy cells. The theoretical limit for packet switched data is approx. k bit/s (using 8 time slots and CS4). A realistic bit rate is 30–80 k bit/s, because it is possible to use max 4 time slots for downlink. A change to the radio part of GPRS called EDGE allows higher bit rates of between 160 and k bit/s. The maximum data rates are achieved only by allocation of more than one time slot in the TDMA frame. Also, the higher the data rate, the lower the error correction capability. Generally, the connection speed drops logarithmically with distance from the base station. This is not an issue in heavily populated areas with high cell density, but may bee an issue in sparsely populated/rural areas.In GSM system, there are 3 ways to bearing WAP: short message, circuitbased data, and GPRS packet data. Compared with GPRS, the first two ways have some limitations:Short message bearing WAP, the length only 160 bytes, it cannot adapt the WAP service data gradually increasing demand. Short message lack of QoS assurance, the time too long, so the short message bearing WAP is not remended.GPRS bearing WAP has a lot of advan