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WLAN Glossary
- Access Point
- A device that transports data
between a wireless network and a wired network (infrastructure).
- IEEE 802.X
- A set of specifications
for Local Area Networks (LAN) from The Institute of Electrical and
Electronic Engineers (IEEE). Most wired networks conform to 802.3,
the specification for CSMA/CD based Ethernet networks. The 802.11
committee completed a standard for 1 and 2 Mbps wireless LANs in 1997
that has a single MAC layer for the following physical-layer technologies:
Frequency Hopping Spread Spectrum, Direct Sequence Spread Spectrum,
and Infrared. IEEE 802.11 HR, an 11 Mbps version of the standard is
expected to be completed by the end of 1999.
- Independent network
- A network that provides (usually
temporarily) peer-to-peer connectivity without relying on a complete
network infrastructure.
- Infrastructure network
- A wireless network centered
about an access point. In this environment, the access point not only
provides communication with the wired network but also mediates wireless
network traffic in the immediate neighborhood.
- Microcell
- A bounded physical space in
which a number of wireless devices can communicate. Because it is
possible to have overlapping cells as well as isolated cells, the
boundaries of the cell are established by some rule or convention.
- Multipath
- The signal variation caused
when radio signals take multiple paths from transmitter to receiver.
- Radio Frequency (RF) Terms:
GHz, MHz, Hz
- The international unit for measuring
frequency is Hertz (Hz), which is equivalent to the older unit of
cycles per second. One Mega-Hertz (MHz) is one million Hertz. One
Giga-Hertz (GHz) is one billion Hertz. For reference: the standard
US electrical power frequency is 60 Hz, the AM broadcast radio frequency
band is 0.55 -1.6 MHz, the FM broadcast radio frequency band is 88-108
MHz, and microwave ovens typically operate at 2.45 GHz.
- Roaming
- Movement of a wireless node
between two microcells. Roaming usually occurs in infrastructure networks
built around multiple access points.
- Wireless Node
- A user computer with a wireless
network interface card (adapter).
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