The WAP application in 1 General packet radio service

At present, the combination of GPRS and WAP is the best solution to make "mobile internet access" reach a new height: GPRS is a powerful bottom transmission and WAP is a high-level application. If WAP is compared to a speeding car, GPRS is a wide and flat highway, and you can ride freely in the wireless information world.

2. Application on equipment

GPRS can be implemented in various devices other than cellular phones, including PCMCIA modems for laptop computers and expansion modules for personal digital assistants and portable computers. RIM, the manufacturer of popular portable e-mail device BlackBerry, cooperated with a GSM supplier named Microcell Telecommunications to study how to use GPRS for information transmission in other wireless systems.

3.GPRS service application

Since the first transmission of text information, wireless data applications have experienced a leap-forward growth. Just looking at the efforts of well-known European and American manufacturers to promote General Packet Radio Service (GPRS), it seems that people can feel that the next generation of mobile data application era is coming. As an important milestone towards the third generation of personal multimedia services, GPRS, a general packet radio service launched at the end of 1999 or the beginning of 2000, will combine mobile communication with data networks and introduce IP services into the broad mobile market. Although the use of mobile data is relatively small at present, in some markets, different user groups are developing rapidly, and the driving force is mainly the commercial market that adopts data services in the mobile field. No matter Ericsson, Nokia or Alcatel, almost all manufacturers promoting GPRS are lobbying operators with the rapid growth of commercial user market.

Packet Mobile Data Communication (GPRS) in GSM system is a basic packet radio service. With packet switching, the highest data rate can reach 164kb//. It can provide GSM users with high-speed data services in mobile environment, and also provide functions such as sending and receiving Emai 1 and Internet browsing.

(1) service application corresponding to GPRS function

GPRS is a new GSM data service, which can provide wireless packet data access service for mobile users. GPRS mainly provides the connection between mobile users and remote data networks (such as networks supporting TCP/IP and X.25), thus providing high-speed wireless IP and wireless X.25 services for mobile users.

GPRS adopts packet switching technology, allowing multiple users to enjoy certain fixed channel resources. If all eight time slots in the TDMA frame on the air interface are used to transmit data, the highest data rate can reach 164 KB/8. The channel resources of GSM air interface can be occupied by voice and GPRS data services. Of course, in the case of sufficient channels, some channels can be defined as GPRS dedicated channels.

In order to realize GPRS network, it is necessary to introduce new network interfaces and communication protocols into the traditional GSM network. At present, GPRS network has introduced GSN(GPRS supporting node) node. The mobile station must be a GPRS mobile station or a GPRS/GSM dual-mode mobile station.

According to the suggestion of ETSI GSM Phase 2+ in Europe, GPRS is divided into two stages (namely 1 stage and 2 stage).

The 1 phase of GPRS will be able to support the following functions and services:

Tcp/IP and X.25 services

New GPRS air interface encryption technology

(2)GPRS additional services

Enhanced short message service (e-SMs)

GPRS packet data charging function, that is, charging according to the amount of data. Among the above functions, TCP/IP and X.25 are the most prominent. GSM network can provide users with services such as e-mail, WWW browsing, private data and LAN access through TCP/IP and X.25.

The specification of the second phase of GPRS is still being worked out, which will provide more new functions and services.

Four. GPRS related technology

1.GPRS technology embodiment

GPRS general wireless packet service is a wireless packet switching technology based on GSM system, which provides end-to-end and wide-area wireless IP connection. Generally speaking, GPRS is a high-speed data processing technology, and the method is to transmit data to users in the form of "packets". Although GPRS is a transitional technology from the existing GSM network to the third generation mobile communication, it has obvious advantages in many aspects. At present, Hong Kong, as the first area to conduct GPRS field test, has achieved good results.

Because of the use of "grouping" technology, users can avoid the pain of disconnection when surfing the internet (the situation is probably similar to using the download software NetAnts). In addition, the method of accessing the Internet using GPRS is different from WAP. Using WAP to surf the Internet is like surfing the Internet at home. After surfing the Internet, you can't use the telephone line at the same time, but GPRS is superior. You can download data and talk at the same time. Technically speaking, GSM will continue to be used for voice transmission (that is, call), while GPRS can be used for data transmission. In this way, the application of mobile phones will be promoted to a higher level. Moreover, the development of GPRS technology is also very "economical", because it can only be developed according to the existing GSM network. GPRS is widely used, including sending and receiving e-mails through mobile phones and surfing the Internet.

At present, the slogan of mobile Internet access is "always online" and "IP in hand". After using GPRS, data can be sent and received in groups, which means that users are always online and charged according to the flow, which quickly reduces the service cost. For the WAP tariff policy of China Mobile/China Unicom, which is still difficult to produce at present, if the CSD (circuit switched data, commonly known as dial-up data) bearer is changed to GPRS, it means that dozens of people will bear the original cost.

The biggest advantage of GPRS is that the data transmission speed is not as fast as WAP. At present, the transmission speed of GSM mobile communication network is 9.6kbytes per second, and the transmission speed of GPRS mobile phone has reached 9.6Kbps when it was launched at the beginning of this year, and now it has reached 1 15Kbps (twice the ideal speed of the commonly used 56Kmodem). So please cherish Nokia7 1 10 and MotorolaL2000. I believe that GPRS mobile phones will give way as soon as they are launched.

2. Grouping technology

The so-called package is to package the date into many independent packages, and then send these packages one by one, which is a bit like sending packages. The advantage of packet switching is that it only takes up bandwidth when there is data to send, and it can be priced according to the amount of data transmitted. It is a reasonable charging method for users, because most of the time and bandwidth of data transmission like the Internet are intermittent. In addition, in the standard of GSM phase 2, GPRS can provide four different coding modes, which also provide different error protection capabilities. Using four different coding methods, each time slot can provide the transmission rates of CS- 1(9.05K), CS-2( 13.4K), CS-3( 15.6K) and CS-4(2 1.4K). ..

3.GPRS network structure

GPRS network is based on the existing GSM network. It is necessary to add some nodes in the existing GSM network, such as GGSN (gateway GPRS support node) and SGSN (serving GSN).

The reference model of GPRS network is shown in figure 1. GSN is the most important network node in GPRS network. GSN has the function of mobile routing management, and can connect various types of data networks and GPRS registers. GSN can complete data transmission and format conversion between mobile stations and various data networks. GSN can be an independent device similar to a router, or it can be integrated with MSC in GSM.

There are two types of GSN: one is SGSN (serving GSN) and the other is GGSN(GatewayGSN). The main function of SGSN is to record the current location information of mobile station and complete the sending and receiving of mobile packet data between mobile station and GGSN. As a gateway, GGSN can connect many different data networks, such as ISDN, PSPDN and LAN. In some literatures, GGSN is called GPRS router. GGSN can perform protocol conversion on GPRS packets in GSM network, so as to transmit these packets to remote TCP/IP or X.25 networks.

In addition, some manufacturers put forward the concept of GR(GSMRegister, GPRS database). GR, similar to HLR in GSM, is a GPRS service database. It can exist independently, or it can be stored by HLR and realized by server or program-controlled switch. The name GR was not specifically mentioned in ETSI's proposal.

The GPRS network structure also introduces the following new network interfaces:

Gn, GSN backbone interface, used between various GSNs.

Interface between Gb, BSS and sGsN.

Interface between Gr, SGSN and HLR.

Interfaces between different GSM networks (different PLMN).

Interface between Gs, SGSN and MSC.