1、中文 2950 字 英文资料原文 INTRODUCTION OF GSM 一、 GSM implication The GSM full name is: Global System for Mobile Communications, Chinese as the whole world two-way charges for cellular phones system, the popular name the whole world passes, is one kind stems from Europes mobile communication technical standar
2、d, is the second generation of mobile communication technology, its development goal is enables the world to be possible to use a mobile phone network standard together, lets the user use a handset to be able good the whole world. Our country used this technical standard in the early-1990s introduct
3、ion, before this uses the honeycomb simulation migration technology, namely the first generation of GSM technology (on December 31, 2001 our country has closed simulation migration network). At present, China moves, China Unicom to have a GSM net respectively, for world biggest mobile communication
4、network. GSM system including GSM 900:900 MHz, GSM1800:1800MHz and GSM1900:1900MHz and so on several frequency bands. GSM (whole world mobile communication system) is one kind widely applies in European and the world other place numeric move telephone system. What GSM use is the time division multip
5、le access anomalous form, and it is the present three kind of digital cordless phones technology (TDMA, GSM and CDMA) uses the most widespread one kind. GSM digitizes the material, and carries on the data the compression, then transmits together with other two user data stream from the channel, othe
6、r two user data stream has the respective time slot. GSM in fact is Europes radio telephone standard, Joint board reported according to GSM the MOU, GSM has 1,200,000,000 users in the whole world, and the user proliferates more than 120 countries. Because many GSM network operator has the roaming ag
7、reement with other overseas operators, therefore works as user after other countries, still might continue to use their mobile phone. An American Famous Correspondence Company Sprint Auxiliary unit, the American person-to-person communication is using GSM to take one kind of wide band person-to-pers
8、on communication service the technology. This kind of person-to-person communication service finally for Ericsson, Motorola as well as Nokia the handset which produces is establishing more than 400 base depots now. Handset includes telephone, short note beeper and intercom. GSM and other technologie
9、s are the wireless mobile communication evolutions, wireless mobile communication including high-speed circuit exchange data, general packet radio system, based on GSM network data enlargement mode mobile communication technology as well as general mobile communication service. 二、 GSM histories In 1
10、998, the goal replaced GSM for the making the third generation mobile phone (3G) the standard 3GPP start. 3GPP also accepted has maintained and continues to develop the GSM standard the work. ETSI is one of 3GPP members. In the development process, the GSM systems function obtains unceasingly richly
11、. It can thus provide a diverse service. The short information service which first introduces by the GSM system (SMS) has provided one kind novel, convenient, the inexpensive communication way. In 1994, GSM has realized based on the circuit switching data traffic and the facsimile service. In 1999,
12、the WAP agreement caused the user to be possible through the handset visit Internet. After 2000, starts the commercial general grouping wireless service (GPRS) to enable the GSM system to be able to provide the data communication by the efficiency higher packet mode. In 2003, the EDGE technology sta
13、rted commercial, has provided the close 3G data communication ability. At present, the 3GPP organization is also developing the GSM standard, with the aim of using already massively deployed the GSM infrastructure, smoothly to 3G technology evolution. 三、 GSM characteristics 1. GSM uses the direct-vi
14、ewing characteristic: The GSM system has several important characteristics: Security beats ability to be good, the network capacity is big, the handset number fruitful in resources, the telephone conversation are clear, the stability not easily is disturbed, the information to be keen, the telephone
15、 conversation dead angle are few, the handset power consumption is low. 2. GSM technical Characteristic: 1. Frequency spectrum efficiency. Because used the highly effective modulator, the channel coding, to interweave, balanced and the speech coding technology, enabled the system to have the high-fr
16、equency spectrum efficiency. 2. Capacity. Because each channel transmission band width increases, causes the frequency multiplying to plant does reduces compared to the request to 9dB, therefore the GSM systems frequency multiplying pattern may reduce to 4/12 or 3/9 even is small (analogous system i
17、s 7/21)； In addition the half speed rate voice codes introduction and the automatic traffic distribution reduce the skip zone cut the number of times, causes the GSM systems volumetric efficiency (each megacycle each plot channel number) compared to TACS system high 35 times. 3. Voice quality. In vi
18、ew of the fact that in digital transmission technology characteristic as well as GSM standard related space connector and voice code definition, when threshold value, the voice quality always achieves the same level, but has nothing to do with the wireless transmission quality. 4. Opening connection. The GSM standard provides open connection, is not only restricted in the space connector, moreover the publication network is direct as well as in network between equipment entity, for example A connection and Abis connection. 5. Security.
