[wsfii-discuss] Blog Post on Freifunk - It's do or die now!

Thu Oct 1 18:12:17 UTC 2015

On Tue, Sep 29, 2015 at 06:27:32PM +0200, Juergen Neumann wrote:
> Dear all,
> 
> we have worked on a rough translation of my recent blog post on
> Freifunk. I hope it is not too bad!? Please halp spread the word:
> http://blog.freifunk.net/2015/its-do-or-die-now

Juergen,

I feel compelled to respond to this,

        Public radio frequencies are auctioned

        Although wifi has proven as a worldwide success story and
        spread in countless numbers of usage scenarios it still
        has one major drawback: The utilized radio frequencies in
        the 2.4 and 5 GHz band are of limited suitability for an
        unimpededed transmission of radio signals: Outside the near
        field they need a line of sight. Even one wall of an
        appartement or a tree can reduce the signal quality
        significantly. Additionally the number of wifi devices in
        agglomerations is so high that the few remaining radio
        channels do not allow a stable data transfer. With the
        migration [from analog] to digital television by far better
        frequencies in the lower radio spectrum become available
        now. But instead of at least partially making this common
        good available for public and unlicensed usage (e.g. wifi)
        it was and is going to be sold to big telecom companies.
        Not many people understand that this is basically comparable
        to privatising water. For the simple reason that in the
        21st century mobile communication achieved a similarly
        important role, as the "digital glass of water" explains
        it quite well already.

I broadly agree that auctioning off frequencies doesn't seem like the
best way to get the most public benefit from them.  Careful, though!  I
don't think the benefits of the lower frequencies are as cut and dried
as commonly assumed.

It is my understanding that at high frequencies, you can create a
selective antenna in a smaller volume than a similarly selective antenna
for a low frequency.  You can build a better smart antenna array in a
smaller volume, too.  Seems to me that that is an important advantage of
high frequencies to weigh.

The impenetrability of walls and trees to 2.4 & 5 GHz waves is the boon
and bane of community wireless.  Bane because those obstacles reduce
your range, boon because they form a backstop for transmissions.  If
your low-frequency transmissions pierce every obstacle in sight, then
your interference range increases and opportunities for spatial reuse
decrease.

What if community wireless lets the constraints imposed by the
high-frequency bands keep it honest and force it to innovate?  Taking
an open-minded look at the crowded channels, is the worst problem the
interference, or is it an unsuitable media-access protocol?  Can you
increase range by using a different method to check for and to correct
frame errors than a single CRC and retransmission scheme?  Can you
exploit the facts that radio transmissions are space-filling and that
even unicast frames are likely to be received by multiple stations, to
build routing and forwarding systems that improve performance by being
more cooperative?  How can copper and fiber integrate with wireless to
make each medium more useful than any medium alone?  When bandwidth is
limited, it is urgent to ask such questions.

Dave

-- 
David Young
dyoung at pobox.com    Urbana, IL    (217) 721-9981