Wilan LIBRA 5800 AP, User Manual

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June 2003 Rev 0 141
Orthogonal
An adjective that refers to the way the many carrier waves in a W-OFDM system affect each other.
The carriers are spaced in such a way that the center frequency of each signal lies in the null spot of
its neighbors. This minimizes interference.
overhead
Anything that reduces the payload capacity of a system is overhead, even if it is useful. Link monitor
data determines transmission statistics, but it reduces the message-carrying capacity of the system
and is considered overhead.
P
path loss
The total loss from one end of the path to the other. This includes propagation losses, cable losses,
and any other losses that affect the system performance.
ping
A method of testing a link. Executing the ping command sends a signal to the remote station. The
station returns the signal. If the signal comes back on time and intact, the link works. See ftp.
polarization
The orientation of the radiating element of an antenna with respect to Earth. The polarization of
antennas is usually described as vertical, horizontal, or circular.
PN
Pseudo-random noise. A code used to change a narrowband signal into a spread spectrum signal.
point-to-multipoint
A wireless system with one base unit communicating with many remote units. In the BWS system,
the AP is the base and the CPEs the remotes.
point-to-point
The simplest wireless system, consisting of a base and a remote.
polling
The AP unit handles multiple CPEs by contacting them in the order they appear in the polling list.
When an AP polls a CPE, they exchange data. The CPE cannot exchange information with the AP
until it is polled again.
Polling List
The order in which the AP contacts the CPEs in its sector.
propagation loss
The weakening of a signal as it travels through the air. Expressed in dB.