[LINK] Power-line broadband
Robin Whittle
rw at firstpr.com.au
Tue Nov 18 19:49:19 AEDT 2008
BPL - Broadband over Powerlines - is a can of worms in every respect.
It is never going to be a significant service for more reasons than
I could be bothered mentioning again.
http://mailman.anu.edu.au/pipermail/link/2005-September/063634.html
http://www.budde.com.au/News_and_Views/2008/April/Smart_Grids_and_BPL.aspx
Richard Chirgwin wrote, in part:
> It really is the curse of telecommunications: there is no technology
> that's cheap over long distances, for single customers, retaining high
> performance. And we thought the tyranny of distance was overcome by
> telecommunications ... we have overcome distance, but only really
> between population centres. The bits in between the bubbles remain
> hard-to-get.
This is true, but there is one interesting new development - the
"white space" frequencies of TV channels.
The idea is that there are a bunch of channels, used by digital TV,
but in any one area, only a handful of these are actually used. So a
radio system for point-to-point and mesh networking can operate on
these frequencies and do radio links with substantial distances and
worthwhile bit rates.
One way of coordinating which frequencies to use is for the
controlling devices to use GPS to know where they are, and to
interrogate a real-time database which gives them instructions on
which bands to use in that area.
http://blogs.zdnet.com/BTL/?p=10688&tag=nl.e539
There needs to be a whole new tech standard for these radio systems,
which fall under the unfortunate classification of "cognitive radio".
The FCC has a similar view to Ofcom in the UK.
http://www.ofcom.org.uk/consult/condocs/clearedaward/
I will post some more links later, under a different thread.
I think it is quite promising for rural and remote areas, since the
UHF frequencies have good propagation compared to the higher
frequencies normally used for WiMax etc, and because there are really
quite large amounts of spectrum available in any one area.
- Robin
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