Wednesday, June 07, 2006
Let me explain...
By Peter Cochrane
Published: Thursday 4 May 2006
Written in Ashville, North Carolina, and despatched via a free home wi-fi service at about 1,450 metres above sea level
Wherever I travel, and from almost everything I now read, I could be forgiven for supposing we are heading for a wire-free future. Whilst on one level this is almost certainly true, on another we are seeing the encroachment of ever increasing amounts of wire (and optical fibre!).
Paradoxically, the more wireless our world becomes, the more wire we have to deploy. The reality is that to realise the dream of on-demand mobile and portable bandwidth we have to deploy thousands of wireless cells. In the vast majority of cases each cell will be connected into the wider network with copper or fibre cables.
Will it matter if people labour under the wireless illusion? I don't think so!
How come? Bandwidth in the wireless spectrum is fundamentally limited, and so is the distance signals can be transmitted. In addition, the reuse of spectrum - and the control and limitation of interference - dictate increasingly small cells as bandwidth demands increase.
There is also a new set of limiters that are not so obvious. In the old wireless regime we carefully planned and limited the use of space and spectrum, and often completed extensive propagation and interference trials as part of that process. But today we are into black-box technology! We just go the store, buy an off-the-shelf system and install it. People can then just roll up and use it, no problem! Testing and planning don't ever seem to be required. And of course there are performance penalties, which sometimes see unexplained glitches and artefacts that cannot be explained. But hey, for the most part it all works well.
I have just been for an early morning walk in the mountains, and all the houses and cabins are served with overhead telephone and CATV via cables strung on poles. Of course there is a high-speed internet service too. And every house seems to have wi-fi. No interference problems here - the separation is 50 metres or more - but down in town it is often as short as five or 10 metres. No matter, it all works!
Only 30 years ago this wi-fi situation would have been an engineering nightmare. Today it is ubiquitous, low cost and effective, even up these mountains!
So what happens next? The inclusion of more intelligent computing power will allow the use and reuse of both the physical and frequency space even more efficiently so we can access more than 100-fold the bandwidth we enjoy today. Antennas that automatically beam form and steer, combined with coding and signalling systems that avoid each other and therefore minimise interference, plus a least transmit energy regime, are only the start.
Just how far have we come? When on the road about 80 per cent of my connection time is now wireless. In just about every home, office and hotel I am offered wi-fi, and the incidence of wired access being on offer is visibly on the decline.
I reckon another two years will see this transformation complete, and the illusion of a wire-free world will take over. But behind all of this will be an increasingly dense network of fibre and wires to get the base-band signals to each wireless node. The connection of nodes to the spine network will remain the exception for all but a very few cases.
Will it matter if people labour under the wireless illusion? I don't think so! After all, the microprocessor has decoupled most people from the realities of technology and this has been a positive advantage. So long as we retain, train and maintain a few people who actually know what is happening and why, it ought to work!