News

Move Over, Moore: It’s Shannon’ Law

8/06/2012 12:01 AM Eastern

A few weeks ago, an engineering elder called to pose this
bit of industrial wisdom: “For the last 20 years, we’ve
seen the monetization of Moore’s Law. From here on
out, we’ll see the monetization
of Shannon’s Law.”

Haven’t heard of Shannon? Welcome
to this week’s translation.

First off, one important distinction:
There are laws, and then
there are “laws.” Think laws of
gravity, motion, thermodynamics
and physics here. Not legal laws, or
laws of unintended consequences,
or marketing lingo that sounds
peppier with “law” in the title.

In that sense, Moore’s Law isn’t technically a law;
Shannon’s Law is a law of physics. It’s a physical law,
meaning it’s true, universal, simple, absolute and stable.

Moore’s Law is more of an economic observation,
named for Gordon Moore, co-founder of Intel Corp., who
wrote a paper in 1965 stating that the number of transistors
(processing power) within chips was doubling about
every 18 months. It’s still true.

By contrast, and more relevant every “connected” day,
is Shannon’s Law. It’s named for Claude Shannon, who
did his work in the 1940s, 20 years before Moore’s.

Shannon’s Law defines “the theoretical maximum
rate at which error-free digits can be transmitted over a
bandwidth-limited channel in the presence of noise.” (It
comes with an equation, but we’ll spare you the math.)

In other words, Shannon figured out a way to calculate
how much stuff can be crammed over a broadband
network, without problems, even when there is noise,
which there always is.

The dramatic rise in broadband usage — upwards of
50% compound annual growth — is true on fixed and
mobile networks. In London last week, some social media
outlets got bogged down because of all the gadgetry
trying to send pictures and videos. We are gunking up
networks.

Which is why it’s important to be able to calculate
throughput maximums on data networks. And to be
able to ease the situation — by adding spectrum or mitigating
noise.

In cable tech circles, invoking Shannon usually means
you’re having a conversation about upstream (home to
headend) signaling. It’s why there’s so much talk about
advanced modulation and finding ways to make that
slender spectral area carry more stuff .

Will Shannon’s Law get monetized like Moore’s Law
did, with a fury of investment and development that lasts
a half century? Let’s hope so, for the sake of clear connections
and unclogged networks.


Stumped by gibberish? Visit Leslie Ellis at www.translation-please.com or www.multichannel.com/blog.
September