Wireless Home Networking - Index of

40
Part I: Wireless Networking Fundamentals
Ad hoc mode isn’t often used in wireless home networks, but it could be used
on occasion to connect two computers to transfer files where no AP is in the
vicinity to create a wireless infrastructure.
We don’t see any real advantage to using an ad hoc network in your home
just to save a few bucks. You can buy a perfectly good wireless home router
for under $50 (and even less when the sales are on!); the capabilities and
ease-of-use you gain from this approach are well worth the minimal cost.
Your Wireless Network’s Power
Station: The Antenna
The main interface between your access point or network interface card and
the network is the antenna. Signals generated and received by your wireless
gear are dependent on a high-quality antenna interface. To be smart in wireless
networking, you need to know the basics about antennas. If you know
how they work, you can better optimize your network.
The newest APs, which use the 802.11n standard (discussed in the section
titled “Industry Standards”), use a special technology called MIMO that uses
advanced signal processing to “shape” the beam coming out of your antennas.
These systems have a special antenna configuration optimized for this
MIMO system; MIMO systems are not designed to be modified with different
antennas.
Access point antennas vary from manufacturer to manufacturer. Many APs
have a single external antenna about five inches long. This type of antenna is
a dipole antenna. Some APs have two external dipole antennas. Dual external
antenna models should provide better signal coverage throughout the house.
APs with dual antennas may transmit from only one of the antennas but receive
through both antennas by sampling the signal and using whichever antenna is
getting the strongest signal — a diversity antenna system.
Typical omnidirectional dipole antennas attach to the AP with a connector
that enables you to position the antenna at many different angles; however,
omnidirectional dipole radio antennas send and receive best in the vertical
position.
The range and coverage of a Wi-Fi wireless AP used indoors is determined by
these factors:
� AP transmission output power: This is the power output of the AP’s
radio, usually referred to as transmission power, or TX power. Higher
power output produces a longer range. Wi-Fi APs transmit at a power