[LINK] National Broadband Network - except it's not national.

[Stilgherrian]

On 08/05/2010, at 10:20 AM, David Boxall wrote:
> On 7/05/2010 10:31 AM, Tom Worthington wrote:
>> ...
>> If the primary way to access the Internet is from a wireless mobile
>> device, then most of the need for fibre to the home disappears.
>> ...
> That's a big if. Is nothing conceivable that can't be achieved "from a 
> wireless mobile
> device"?
> 
> We need a network with enough headroom for future developments. 
> Developments beyond what we can foresee. Otherwise, we risk ending up 
> with something that's obsolete before it's completed.

Also, when considering what's possible with wireless devices, now or in ANY future, one does have to consider the Shannon–Hartley theorem.

    http://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem

Brief version, translated into practical terms: There's only do much data you can transmit over a particular frequency at a particular power. Or, if you prefer, you share your bandwidth with all the other users on any wireless link. If you want to increase the capacity for everyone, you end up with a huge number of close-spaces transmitters, which then have to be linked in some way -- such as with fibre.

I also live under the flight path to Sydney Airport's runway 16R. When they activate the navaids, the 500MW signal of a certain comms device overloads every Wi-Fi connection in the house, which then takes a minute or two to recover. Wireless IS subject to interference -- and dead spots and so on -- and is not to be trusted.

Stil


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