Building the networks

The Advanced Mobile Phone Service (AMPS) technology perfected in 1983 in the USA was sold under licence to other parts of the world. TACS allowed direct dialling by and to users, and the mobile phones were connected to smaller, low-powered base stations so more calls could be made using the same number of frequencies. Both these pioneer mobile phone services operated on TACS in the 900MHz frequency range.

All telephones are only as good as the network supporting them - and that's certainly the case when we use a mobile phone. With cellular networks, design and equipment not only dictates whom we can call - but whether we can call at all. 'No network coverage' are three of the worst words for any mobile user.

Mobile services arrive in the UK
The Advanced Mobile Phone Service (AMPS) technology perfected in 1983 in the USA was sold under licence to other parts of the world. In the UK, AMPS was developed into a somewhat more sophisticated system called TACS - Total Access Control System. The advantages of TACS were that it allowed for higher numbers of subscribers and enabled transmitters to use lower power and achieve more effective re-use of frequencies.
TACS allowed direct dialling by and to users, and the mobile phones were connected to smaller, low-powered base stations so more calls could be made using the same number of frequencies.
Cellnet, (now 02) a then British Telecom and Securicor joint venture cellular radio service, was launched on January 7, 1985. It replaced the existing radiophone service operated by British Telecom (now BTplc). Its competitor, Racal Vodafone, (now Vodafone) was launched the same year. Both these pioneer mobile phone services operated on TACS in the 900MHz frequency range.

ETACS is developed (1987) : expanding the reach
Britain's first generation mobile phone system, TACS, was a great success.
Although the service providers Cellnet ( now 02) and Vodafone were supposedely in competition, their line rental and call charges were virtually identical, which meant they shared the expanding market more or less equally between them.
Early mobiles were expensive to buy and to use, with the first Motorola hand portable mobile retailing at almost £3,000 and line rental around £30 per month, with calls costing 25p per minute.
Even so, more and more mobiles were sold, expanding call volumes and network traffic so that extra capacity was needed, particularly in metropolitan areas.
So Cellnet and Vodafone persuaded the government to release additional frequencies and in 1987 Extended TACS (ETACS) was born, using frequencies freed up from military allocations. ETACS is used today for most modern mobile phone sytems, even some of the satellite based ones.

Creating capacity : making mobiles useful
Lack of network capacity is particularly crucial to mobiles because it not only restricts whom you can call - but whether your phone will work at all.
The first cellular systems had 1,000 channels - that was how many people could be talking at once in any one cell or the cells touching it.
Soon, capacity problems began to occur during busy periods, when users could not always get a line.
The answer was the introduction of frequency re-use and additional allocations. Frequency re-use was a simple matter of adding more base stations but reducing transmitter power so the same channel could be used at the same time by more people across the country without interference problems.
Entirely new frequencies were made available as well, but this meant new phone designs were needed to exploit the additional channels. Currently all mobile phones sold in Europe are dual band, capable of working on all frequencies allocated for cellular radio. The popularity of the mobile phone shows no sign of slowing down, with more than 674 being sold globally during 2004. Latest developments for this must have technology include the much hyped third generation phone (3G) with its ability to handle large amounts of data transfer such as video and music. But it won't end there as the future promises more innovative ideas including mobiles with hard drives.

How phones have shrunk : smaller and smarter
The first handsets used when Cellnet (now 02) and Vodafone opened their mobile radio systems in 1985 were nicknamed 'bricks' - and little wonder.
Handling the super lightweight pocket telephone of today alongside one of those heavyweights makes you realise how far technology has progressed - today's handsets will fit into a pocket or handbag whereas only a briefcase was big enough to carry the 1985 model.
The battery is the most obvious change - today's lithium ion power packs are about one fifth the size and weight of the huge nickel cadmium batteries of the mid 1980s, provide four times the life and can be recharged easily.
But it's not all down to the batteries - the electronics have changed to become less power hungry and the networks have improved, so that telephones don't have to transmit so far and can connect more quickly. This means they consume less power and can get by with smaller capacity batteries.