Networker: Technology for the new millennium


Technology for the new millennium

There is a new technology in the air. It is called CDMA (Code Division Multiple Access). It holds huge promise for mobile phones. It is being spoken of as the possible basis for a single international mobile phone standard. It is also being applied to just about every other mobile application.

CDMA breaks the rules for transmission of signals through the air. Radio, television, mobile phones and other "wireless" technologies work because a transmitting antenna can generate "waves" of electromagnetic radiation.

This radiation includes many common forms, such as radar, microwaves and radio waves. Each of these can be distinguished by the size of the waves. The smaller they are, the more waves pass a particular point each second (their "frequency"). They all travel at something approaching 300,000 kilometres per second, the "speed of light". So when you listen to radio station FM104.7, you are tuning your radio to receive waves with a particular frequency, in this case 104,700,000 waves per second.

What your radio, television or mobile phones pick up, however, is the signal you want plus any noise with the same frequency. If the noise is too great (for example, if you are standing near an electric motor which is producing noise on many frequencies), you don't hear any signal at all. This is the traditional rule: keep the power of the signal greater than the power of the noise. It is described mathematically by the "signal to noise ratio".

CDMA ignores this rule. Instead the signal is transmitted with much less power than the surrounding noise, across many frequencies. The difference is that this noise-like signal is sent out using a particular code. This code can then be used at the receiver to pick out the original signal. All the accompanying noise will not match this code, and will be discarded.

The technology also has inherent security. If you don't know the transmitting code and you listen, all you will hear is noise. This also makes it difficult to block the signal.

From a technical point of view, it defies common sense. It is clever, simple and new, having been developed since the early 1970s.

But here is the catch. CDMA is a form of "spectrum spreading". The idea behind spectrum spreading has existed at least since the early 1940s, and a working model proving the technology was built in the 1940s. That's when it came to the attention of the US military, attracted not just by its secrecy but also by its reliability.

From the 1940s until 1970 it remained a military secret, banned from non-military development or use. This itself is not a secret. Run a search on CDMA on the internet, and you will find many references to this fact.

The secret is the list of all the other technologies locked away in some military vault.

Technology wastage tends to take two forms in capitalist society. The first is the wastage of brilliant technical innovation, crushed by the blind stupidity of the "market". This often takes the form of dangerous and dirty technologies being used when clean, safe alternatives are available.

The second is the deliberate suppression of technical discoveries for commercial or military purposes.

In the next few weeks massive media hype will be devoted to what the next millennium will bring. Among other things, one can hope for the emergence of a society incorporating a humanistic and rational use of technological discovery.

By Ian Peters