Mobile working Toolkit

Drowning in wireless spaghetti

Tags:
Wireless

Rupert Goodwins ZDNet.co.uk

Published: 01 Nov 2005 13:00 GMT

...every territory adopted different frequencies and signalling protocols and was thus mutually incompatible. Europe decided to use TDD for GSM, the first 2G phones; America had a variety of technologies reflecting its much more fragmented market, but settled on CDMA for its 2G system.

There are also various ways that the information can be encoded for transmission, quite separate from the way the frequencies are selected and used. Each decision affects a number of factors: power consumption, how many transmitters can operate in a particular area, how far the transmission reaches, how resistant a signal is to interference, how much data can be carried, how easy it is to interleave voice and data and so on.

Maximum confusion
This was the background against which the International Telecommunications Union decided to start its IMT-2000 project, which aimed to create a single third generation (3G) standard for the world unifying TDD, FDD, CDMA under one banner. After 10 years, it created not one but five standards — CDMA-TDD, CDMA-FDD, CDMA, CDMAx3 and TD-SCDMA, which have largely been deployed along regional lines and have acquired second or even third names in a successful effort to spread maximum confusion.

The major European 3G standard is called W-CDMA (W for Wideband — it's really CDMA-FDD — but it's also called UMTS and GSM ). America's CDMA networks have moved to 1xEV-DO (Evolution Data Only) for 3G, which is part of a different development called cdma2000. China is using TD-SCDMA, which has Chinese intellectual property in it.

And if that's not enough, there is absolutely no agreement over what 4G might be. There are signs that UMTS-TDD is trying to acquire that name, but as the standard is part of the 3G specification suite this is pure marketing spin. Beware of anyone claiming 4G — they're not, and will not for years to come.

For a glossary of wireless standards, click here...