Wireless Home Networking - Index of

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Part I: Wireless Networking Fundamentals
the system can talk to every other radio, and in doing so they can retransmit
the commands you send throughout the home. The most common metaphor
here is the frog in the lily pond — the frog can’t jump all the way across the
pond in one fell swoop, but he can bounce from pad to pad until he finds his
way across. A wireless home control network does the same thing, “organizing”
itself and providing a route throughout the home for your control signals.
The network effect is in full effect in mesh networks like this. In case you’re not
familiar with it, the network effect states that the value of networked devices is
exponentially related to the number of those devices. (For example, if only one
fax machine existed in the world, it would be useless; if millions exist, they
can be very useful.) A similar thing is true for mesh networked home control
devices (called modules). One or two would work okay, if they were near each
other, but when a home has dozens (or even hundreds), all sorts of devices can
communicate with each other and the whole network will perform significantly
better.
The two main technology competitors for this (still new) marketplace are
� ZigBee: ZigBee is a wireless automation networking standard based on
an international standard (called IEEE 802.15.4 — similar to the 802.11
standards used for Wi-Fi networks). As we mention earlier, ZigBee systems
use a peer-to-peer networking infrastructure, called mesh networking,
to reach throughout the home. ZigBee provides a data rate of 250
Kbps, while using chips that are inexpensive to manufacture. A group
called the ZigBee Alliance (www.zigbee.org) — similar to the Wi-Fi
Alliance — is helping manufacturers bring ZigBee products to market
and helping ensure that the products work well together. As we write,
only a few dozen ZigBee products are on the market, but dozens of manufacturers
have joined the alliance.
� Z-Wave: A Danish semiconductor company called Zensys (www.zen-sys.
com) has developed a competitor to ZigBee called Z-Wave. Z-Wave is a
wireless, mesh, peer-to-peer automation networking protocol that’s similar
to ZigBee. Z-Wave systems operate at speeds of up to 9.6 Kbps (slower
than ZigBee but still more than fast enough for home automation and
control). Z-Wave products are still new to the market, but several major
manufacturers, such as Leviton (www.leviton.com) and Wayne Dalton
(www.waynedalton.com), are shipping products using Z-Wave.
ZigBee and Z-Wave are similar systems that do not work together. That is to
say, a ZigBee chip and a Z-Wave chip can’t talk to each other and work
together in a home control network. But they can both be installed in the
same home without causing interference nightmares. So while your ZigBee
and Z-Wave networks can’t directly interoperate, there’s no problem with
having both in your home (if you choose to do so) — for example, you could
have a Z-Wave lighting control system and use ZigBee to control your heating
and air-conditioning systems.