Chapter 24:General Packet Radio Service (GPRS)

     The introduction of wireless communication has allowed many people around the world to live their lives and conduct business in ways that were never before possible.Millions of cellular subscribers have become accustomed to always having a telephone with them wherever they go.Now, businesses are wanting to be able to connect to the office when they are out of the office so they can check their email, search on the Internet, access company files, send faxes and data whenever and wherever it is needed.Currently, there are numerous wireless data services available, but a new technology, General Packet Radio Service, offers much excitement to consumers. Indeed, the demand for communications and new technology is greatly growing based on the needs of the people and business especially in the Internet.

What is GPRS?

     General Packet Radio Service, more commonly known as GPRS, is a new non-voice, value added, high-speed, packet-switching technology, for GSM (Global System for Mobile Communications) networks. It makes sending and receiving small bursts of data, such as email and web browsing, as well as large volumes of data over a mobile telephone network possible. A simple way to understand packet switching is to relate it to a jigsaw puzzle. Image how you buy a complete image or picture that has been divided up into many pieces and then placed in a box. You purchase the puzzle and reassemble it to form the original image. Before the information is sent, it is split up into separate packets and it is then reassembled at the receivers end. The main benefits of GPRS are that it reserves radio resources only when data is available to send, and it reduces the reliance on traditional circuit−switched networks.

       GPRS offers a continuous connection to the Internet for mobile phone and computer users. Users may need to be connected to a data communication network (such as a LAN, WAN, the Internet, or a corporate Intranet), but that does not mean they are sending and receiving data at all times. Data transfer needs are not generally balanced.In the majority of cases, users will tend to send out small messages but receive large downloads.Therefore, most of the data transfer is in one direction. GPRS is expected to provide a significant boost to mobile data usage and usefulness. It is expected to greatly alter and improve the end-user experience of mobile data computing, by making it possible and cost-effective to remain constantly connected, as well as to send and receive data at much higher speeds than today.Its main innovations are that it is packet based, that it will increase data transmission speeds, and that it will extend the Internet connection all the way to the mobile PC – the user will no longer need to dial up to a separate ISP. 

Method of Operation

       GPRS gives GSM subscribers access to data communication applications such as e-mail, corporate networks, and the Internet using their mobile phones.The GPRS service uses the existing GSM network and adds new packet-switching network equipment. GPRS employs packet switching, which means that the GPRS mobile phone has no dedicated circuit assigned to it.Only when data is transferred is a physical channel created.After the data has been sent, it can be assigned to other users.This allows for the most efficient use of the network.

       When packet-switched data leaves the GPRS/GSM network, it is transferred to TCP-IP networks such as the Internet or X.25. Thus, GPRS includes new transmission and signaling procedures as well as new protocols for interworking with the IP world and other standard packet networks. Mobile phones currently available do not work with the new GPRS technology.The industry’s mobile phone vendors are working on new phones that will support both GSM and packet switching.There is also a possibility in the future, that laptops and PDA’s (Personal Digital Assistants) will have GPRS phone integrated in them.

GPRS Network Architecture

A Comparison of Data Transfer Speeds (in Kbps)

    GPRS could possibly be the technology that will allow consumers to really begin to sue the mobile Internet.GPRS is considered one step ahead of HSCSD (High Speed Circuit Switched Data) and a step towards 3G (Third-generation) networks. It is the step to 2.5G for GSM and TDMA (Time Division Multiple Access) service providers.Cingular and AT&T are both currently the standard.

      GPRS is ideal for Wireless Application Protocol (WAP) services because of the cost saving WAP over GPRS bring to mobile operators and cellular consumers.Costs are reduced because GPRS radio resources are only needed while the message is being transferred.For the end user, that means you only pay for the time it takes to download the data and information that you need.For the GSM operator, that means that you will be able to provide high speed Internet access to consumers at a reasonable cost, because you will bill mobile phone users for only the amount of data that they transfer rather than billing them for the length of them that they are connected to the network.

    With GPRS-enabled mobile phones, services are received faster than with traditional GSM phones.GPRS offers an increase in data throughput rates, so information retrieval and database access is faster, more usable and more convenient.At its best, GPRS is transparent, allowing the user to concentrate on the task in hand rather than on the technology.

GPRS History

DATEMILESTONE

User Features

3 TO 10 TIMES THE SPEED

     The maximum speed of 171.2 kbps, available through GPRS, is nearly three times as fast as the data transmission speeds of fixed telecommunications networks and ten times as fast as the current GSM network services.

INSTANT CONNECTIONS – IMMEDIATE TRANSFER OF DATA

    GPRS will allow for instant, continuous connections that will allow information and data to be sent whenever and wherever it is needed. GPRS users are considered to be always connected, with no dial-up needed.Immediacy is one of the advantages of GPRS (and SMS) when compared to Circuit Switched Data.High immediacy is a very important feature for time critical applications such as remote credit card authorization where it would be unacceptable to keep the customer waiting for even thirty extra seconds. 

NEW AND BETTER APPLICATIONS

     General Packet Radio Service offers many new applications that were never before available to users because of the restrictions in speed and messaged length.Some of the new applications that GPRS offers is the ability to perform web browsing and to transfer files from the office or home and home automation, which is the ability to use and control in-home appliances.

Network Features

PACKET SWITCHING

     From a network operator perspective, GPRS involves overlaying packet based air interference on the existing circuit switched GSM network.This gives the user an option to use a packet-based data service.To supplement a circuit switched network architecture with packet switching is quite a major upgrade.The GPRS standard is delivered in a very elegant manner – with network operators needing only to add a couple of new infrastructure nodes and making a software upgrade to some existing network elements.

 SPECTRUM EFFICIENCY

     Packet switching means that GPRS radio resources are used only when users are actually sending or receiving data.Rather than dedicating a radio channel to a mobile data user for a fixed period of time, the available radio resource can be concurrently shared between several users.This efficient use of scarce radio resources means that large number of GPRS users can potentially share the same bandwidth and be served from a single cell.

INTERNET AWARE

     For the first time, GPRS fully enables Mobile Internet functionality by allowing interworking between the existing Internet and the new GPRS network. Any service that is used over the fixed Internet today – File Transfer Protocol (FTP), web browsing, chat, email, telnet – will be as available over the mobile network because of GPRS.In fact, many network operators are considering the opportunity to use GPRS to help become wireless Internet Service Providers in their own right.

     The World Wide Web is becoming the primary communications interface – people access the Internet for entertainment and information collection, the intranet for accessing company information and connecting with colleagues and the extranet for accessing customers and suppliers.Web browsing is a very important application for GPRS. Because it uses the same protocols, the GPRS network can be viewed as a sub-network of the Internet with GPRS capable mobile phones being viewed as mobile hosts.This means that each GPRS terminal can potentially have its own IP address and will be addressable as such.

SUPPORTS TDMA AND GSM

     It should be noted that the General Packet Radio Service is not only a service designed to be deployed on mobile networks that are based on the GSM digital phone standard.


Source: http://misnt.indstate.edu/harper/Students/GPRS/GPRS.html
            Broadband Telecommunications Handbook (VPN 3GW GPRS MPLS VoIP SIP).pdf