Way back in the dim and distant past, the only way of talking to someone a long way away was by shouting. Design innovations followed. The yodel refined shouting technique into bursts of information and the whistle then codified it into an efficient form of communication (providing you knew what peep, PEEEEP, pee-eep stood for, of course).

Fortunately for us however, technology then stepped in to save the day, providing us with a whole range of communications options to get our message across. This entry takes a general look at some of those, the networks which support them and takes a guess at predicting what else we might be able to do with them other than just talk. Along the way, we'll also meet rather a lot of acronyms, upon which the telecommunications industry seems to thrive...

European Mobile Networks

GSM

At the time of writing, most of Europe currently uses a system known as GSM - Global System for Mobile Communication - or 2nd Generation mobile. 1st Generation was the analogue system popular in the early 1980s, sporting handsets which doubled as exercise weights. It was a popular system with some young professionals, but they only used it to annoy. Some would say this skill has travelled across with the new network technologies too... Japan and the US both mainly use different systems to those described here. One of the stated aims of UMTS (see below) is to remove this disparity.

GSM is great for voice communication, beating shouting hands down and, you could say, solves the problem of what most people want from a mobile phone. However, since we're now living in an information age, some people's needs have progressed beyond voice. They want to send and receive data. GSM allows for this in two ways: the first uses a system originally designed for maintenance and alerting operations known as SMS (Short Message Service) and has subsequently proved to be quite popular. The second provides for more general data transfer, with a 9.6kbs¹ data channel available for each user.

However, data transmission isn't one of GSM's strengths. Call set-up times are long, as are the calls themselves as people end up waiting for long periods of time for that huge email attachment to route itself down to their phone. Data transfer is also done over a standard call channel so, if you wander into a tunnel and lose your connection, chances are you'll have to start again from scratch. Not good.

The first attempt to solve this problem looked at trying to make the best use of the capabilities of the network which was already there, minimising the amount of data you had to transfer to get at what you wanted to know. This led to the development of WAP (Wireless Application Protocol²), a family of standards dealing with everything from efficient data transfer over a slow network, to displaying data on a limited capability terminal. WAP suffered, however, from bad marketing for while it was making the best use of the technology currently available, it quite plainly wasn't as good as the stuff people were used to seeing on their desktop computers. Clearly both the capabilities of the terminals and the network are going to have to improve to make really usable data services a possibility.

GPRS

The limitations of GSM for data connections have now led to the development of GPRS (General Packet Radio System). This provides a packet-based data overlay for the GSM network. In English, this means that instead of the long call set-up times needed in the past, future terminals will, in effect, be always connected to a network, ready to send and receive data at any time in small 'packets'.

GPRS also improves the amount of data which can be transferred at one time, from the 9.6kbps offered by GSM, up to around 40-50kbps, depending on the coding technique being used. GPRS uses four different coding strategies to cram extra data into the space used by GSM. It can also let one user use up to eight data-slots at the same time, (although commercial systems will probably only allow up to four).

GPRS's tricks don't end there however. Whereas GSM can only support either a voice or a data call at any one time, GPRS terminals will be able to either interrupt data transmissions when an incoming voice call is recognised, or, potentially, maintain simultaneous voice and data connections.

GPRS, HSCSD (High Speed Circuit Switched Data) and EDGE (Enhanced Data for GSM Evolution or possibly Enhanced Data GSM Environment, depending on who you ask - a kind of mega-GPRS) are collectively known as 2.5 Generation services (2.5G) as they provide a stop-gap between 2G (GSM) and 3G (UMTS) which we'll look at next.

UMTS

UMTS (Universal Mobile Telecommunications System) is the holy grail of mobile communications. It offers a single network standard which will work anywhere in Europe, the US and Japan, unifying the different systems currently in use. In has the potential to support data-rates of up to 2Mbps assuming an in-building pico-cell network. This is basically lots of small cells in an office, a bit like a Wireless LAN in this case and likely to be provided as an extension to an office network, rather than a general public connection route. In metropolitan areas, data speeds of up to 384kbps are planned, although the precise bit-rate you're actually going to get depends on all sorts of things - how far you are from a transmitter, how many other people are in the same cell as you and how the network's been provisioned to name but three, but it's still going to be fast. UMTS can also play all the clever network tricks used by GPRS too, so it's a nice thing to have.

Unfortunately, it does need a new network, (up till now we've got away with patching the old one) and a broadcast license, which are both expensive - most of the UK licenses went for around £4 billion a pop, which means that in order for the network providers to make any money back on the deal they're going to have to come up with some exciting new services to make people want to use their systems. Fortunately, for them and us, there are already some good ideas floating around out there, leading to all sorts of fun new things we might be able to do while we're out and about.

Future Mobile Applications

Obviously, all the things you might expect to be able to do with a functional wireless terminal and a faster data network, you will be able to do. So, if you want to read your email, browse the web, read H2G2 and all of those other funky things you can do over the Internet, you'll be able to do them on your mobile device. Indeed, you can already do all those things if you've got the right gadgets³. However, future mobile applications have the potential to offer services over and above what you might initially expect - a couple of those areas are covered below.

Location-based Services

The big advantage a mobile terminal has over a fixed one is, obviously, that you can move it around. If you then have a system which can track where that terminal is, combined with an always-on data connection, such as that provided by GPRS/UMTS, then you've got the potential to make use of that positional knowledge in all sorts of interesting ways.

Imagine a terminal which automatically looks up the h2g2 entry on Gothenburg because it picks up that fact you've just entered the city, pulling back a local street map to go with it and recommending a local restaurant, all without you having to tell it a thing. Need a taxi? No problem, click on a local firm's site, your terminal passes on your name and location and there's one on its way. You can even watch its progress on the street map in front of you, safe in the knowledge that it's the closest one to where you are.

The technology to track terminals in this way is already commercially available. GPS systems can locate people to within a few metres and already GSM networks are starting to make use of cell-id⁴ to deliver local traffic information and contact details for local hotels and restaurants to a resolution of a mile or so. UMTS, with smaller cell sizes in metropolitan areas will allow more accurate resolutions.

Obviously there are serious security considerations to be considered before these services could be delivered in practice. You probably don't want everyone to know where you are all the time for example, but the potential benefits are clear.

Mobile Multimedia Services

As mobile PDAs⁵ become more technically capable and network speeds improve, streamed audio and video services start to become a viable proposition. Future 3G terminals are likely to have embedded video cameras for video conferencing (or just gloating to your friends back home while you're sitting on the beach on holiday). Digital camera based systems for static pictures are already starting to make an appearance. Rather than send a postcard, take a quick snapshot, link the picture to an email and send it home, all from the beach.

Audio and video delivery services will also start to make an appearance. 384kbps can support near-broadcast quality video and audio on a small screen. Perhaps you might like to be notified whenever your favourite team score a goal, complete with video footage from the match? Fed up with carrying all your CDs around and then still never having the song you want to listen to? Hook up your mobile terminal to an Internet music store and boogie along to whatever song you like. Worried that someone's breaking into your house? Link into your home security system and check your closed-circuit TV feed to make sure everything's safe.

Again, some of these services can be delivered even over a GSM network. Video streaming is possible even at 9.6kbps, admittedly with pretty poor quality and rather a lot of delay⁶ but as speeds improve, so will the services on offer.

Future Terminal Developments

There are currently two different approaches in the terminal market regarding the best way to link a PDA to a mobile network: the first is network integration. Terminals running all three of the major PDA operating systems are appearing with integrated network functionality, providing a single terminal for all your diary, email, telephone, web browsing and organiser needs. There are also dedicated terminals designed for corporate users offering secure email links over GPRS, providing a mobile outpost for their corporate Intranets while they're on the move.

An alternative approach keeps the network functionality separate from the terminal itself. This uses plug-in modules or infra-red links to let your PDA talk to the outside world. This has the advantage that you can then change the network route to your terminal, as technology improves, but it does mean you've then got another box to carry around with you. Bluetooth forms an interesting section of this approach, providing a local wireless link between devices a few metres away from each other, removing the need for physical bits of wire connecting the various boxes together.

Further Information

Cellular communication is a huge subject area and the above information barely scratches the surface. If you really want to get down and dirty with the technology, the links below might be a good place to start:

• Mobile Streams - A good general starting point with links to lots of information on the above technologies from various areas.

• GSM World - Another good starting point. Some good introductory articles about the various technologies, and news updates about what's happening in the mobile world.

• The Mobile Applications Initiative - General information on GPRS and 3G technology

• Mobile News UK - What's happening in the UK Mobile market.

• Bluetooth Information - The official Bluetooth site.

• The 3GPP home-page - 3GPP is a development partnership group tasked with the creation of the standards for 3G technology.

• The 3GIP home-page - 3GIP is a development partnership group advocating the incorporation of IP data standards into 3G protocols. They promote standards into the 3GPP.

• PDA Buzz - A good news site for what's happening in the PDA market.

• WAP Forum - The people behind the WAP specification.