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).
