GPRS - Something to do with my phone, right?

By: Rob O'Connor

You might be forgiven for thinking that the letters GPRS are just another acronym the mobile operators use to confuse you. But really they're not…honestly.

GPRS, or General Packet Radio Service, is a relatively new way of sending and receiving information to and from a mobile phone. It operates similarly to the Wireless Application Protocol (WAP) in the fact that web pages may be viewed on your telephone screen, but they differ in the way they use a dial-up connection. With WAP a user dials-up their service provider, does whatever they want to do and then disconnects. The user is then charged for the duration of the phone call. A GPRS-enabled phone however, offers users an "always-on", high-capacity, high-speed connection to Internet-based information and services. Charging is based on the amount of data the user sends/receives. So imagine this scenario:

Fintan is an engineer working on-site somewhere and is waiting for an important email to arrive from his boss. With his standard WAP phone, he must dial up every time to check his email for new messages. Each time he does this, he incurs a charge. However with his GPRS phone, he just sits there and when his boss sends the email, he is notified instantly. He is only charged for reading this one email. Using GPRS it is far quicker, easier and (most importantly) cheaper to use the Internet from a mobile device.

So how does it work? GPRS is built on the idea of a packet-switched network. Packet-switched networks have often been described as comparable to moving a building from one location to another. So let's say we want to move a house from Dublin to Waterford. It would be impractical (and practically impossible) to transport the building in one go. The solution is to disassemble the house, label the various bricks, components, etc, load them onto trucks and begin transportation. The bricks may not arrive in Waterford in the same order that they were sent, since the drivers may take different routes to deliver their

loads, some may drive faster than others or for various other reasons. However, this doesn't really matter since we know the order that the bricks are to be put together based on the labelling structure we devised in the beginning. And soon after all the bricks have arrived, we can reassemble the house perfectly in Waterford (in theory at least).

Now apply this system to moving data around a network. A Server receives a request from a Client for a block of information. The Server breaks up the information into packets and begins transmitting the data across the network. The Client starts receiving these packets and put them back together so as to produce the requested information. If a packet gets lost along the way, the Client can ask for it to be re-transmitted, thus ensuring the Client receives all the data it needs. The best example of an implementation of this type of network is the Internet. So you could have been using a packet-switched network all this time without realising it! GPRS uses this type of system to transfer data between mobile phones and other networks.

GSM (Global System for Mobile) is the 2G of mobile phone networks and 3G networks are a little bit away yet. GPRS sits somewhere between the two of these and so has been dubbed 2.5G. So now you know a bit about GPRS, how can you use it? Both Vodafone and O2 offer GPRS services to customers with GPRS-enabled phones, such as the Nokia 6210, 6310, 8310, or the Motorola V66, V80.

So should you use GPRS? Well if you use WAP regularly, you could probably reduce your costs by switching to GPRS. If you foresee the need for a mobile data connection in your near future, GPRS might be for you.