General Packet Radio Service is a standard for wireless communications which runs at speeds of up to 150 kilobits per second, compared with current GSM (Global System for Mobile Communications) systems' 9.6 kilobits.
GPRS, which supports a wide range of bandwidths, is an efficient use of limited bandwidth and is particularly suited for sending and receiving small bursts of data, such as e-mail and Web browsing, as well as large volumes of data. See the User Benefits of GPRS and Network Features of GPRS below.
User Benefits of GPRS
A new non-voice value added service that allows information to be sent and received across a mobile telephone network, the General Packet Radio Service (GPRS) supplements today's Circuit Switched Data and Short Message Service (SMS).
No relation to GPS (the Global Positioning System - a similar acronym that is often used in mobile contexts), GPRS offers users the following features:
3 TO 10 TIMES THE SPEED
Theoretical maximum speeds of up to 171.2 kilobits per second (kbps) are achievable with GPRS using all eight timeslots at the same time. This is approximately three times as fast as the data transmission speeds possible over today's fixed telecommunications networks and ten times as fast as current GSM network Circuit Switched Data services.
INSTANT CONNECTIONS - IMMEDIATE TRANSFER OF DATA
GPRS facilitates instant connections whereby information can be sent or received immediately as the need arises. No dial-up modem connection is necessary. This is why GPRS users are sometimes referred to be as being "always connected". 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
GPRS facilitates several new applications that have not previously been available over GSM networks due to the limitations in speed of Circuit Switched Data (9.6 kbps) and message length of the Short Message Service (160 characters). These applications range from web browsing to file transfer to home automation - the ability to remotely access and control in-house appliances and machines.
To use GPRS, the user will need:
Network Features of GPRS
From a network operator perspective, GPRS involves overlaying a packet based air interface 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. However, as we shall see later, 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.
With GPRS, the information is split into separate but related "packets" before being transmitted and reassembled at the receiving end.
Packet switching is similar to a jigsaw puzzle - the image that the puzzle represents is divided into pieces at the manufacturing factory and put into a plastic bag. During transportation of the now boxed jigsaw from the factory to the end user, the pieces get jumbled up. When the recipient empties the bag with all the pieces, they are reassembled to form the original image. All the pieces are all related and fit together, but the way they are transported and assembled varies. The Internet itself is another example of a packet data network, the most famous of many such network types.
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 numbers of GPRS users can potentially share the same bandwidth and be served from a single cell.
The actual number of users supported depends on the application being used and how much data is being transferred. Because of the spectrum efficiency of GPRS, there is less need to build in idle capacity that is only used in peak hours. GPRS therefore lets network operators maximize the use of their network resources in a dynamic and flexible way, along with user access to resources and revenues.
GPRS should improve the peak time capacity of a GSM network since it simultaneously:
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. These are all derivatives of the World Wide Web aimed at connecting different communities of interest. There is a trend away from storing information locally in specific software packages on PCs to remotely on the Internet.
When you want to check your schedule or contacts, instead of using something like "Act!", you go onto the Internet site such as a portal. Hence, 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 mobile phone standard.
The IS-136 Time Division Multiple Access (TDMA) standard, popular in North and South America, will also support GPRS. This follows an agreement to follow the same evolution path towards third generation mobile phone networks concluded in early 1999 by the industry associations that support these two network types.