Eion LibraPlus 5845, Руководство пользователя, Страница: 132 / 140

From the host, the manager configures agents, or polls agents for
information.
MIB Management Information Base. A set of commands that you can
execute using the SNMP Manager to access the MIB database. A
standard MIB and a EION-customized MIB store information
relevant to the operation of a wireless network.
Multipath Interference As a radio signal travels, it may reflect off objects in the environ-
ment and take various paths to the receiver. As a result, the signal
arrives at the receiver at different times, confuses the receiver, and
causes bit errors and processing delays. A related type of interfer-
ence is multipath fading, in which a reflected signal shifts out of
phase with the original signal and cancels it.
N
Near Line of Sight (NrLOS):
Suburban NrLOS is a visually-obstructed line of sight between two transmit-
ting devices but a straight line can still be drawn between them.
Any combination of reflection, refraction and diffraction on a
direct ray between the transmitter and receiver may have occurred.
Non Line of Sight (NLOS):
Dense Urban No line can be drawn between two transmitting devices. Total
visual blockage has occurred between the transmitting and receiv-
ing devices. Extremely large amounts of reflection, refraction and
diffraction can occur on a direct ray between the transmitter and
receiver.
Null An RF signal component with a smaller amplitude than the rest
of the RF signal in multipath interference. Nulls are caused by
subtractive combination as a result of multipath fading.
Null Depth The ratio in dB between the strongest OFDM carrier and the
weakest carrier in multipath interference. A null depth of zero in-
dicates that there is no multipath reception.
O
Obstructed Line of Sight
(OLOS): Urban OLOS is a partially blocked elliptical cylinder, whose diameter
depends on frequency and distance, that can be drawn between
two transmitting devices. An object is infringing or cutting into
the cylinder. OLOS can occur in various degrees of severity. Large
amounts of reflection, refraction and/or diffraction occur on a
direct ray between the transmitter and receiver.
ODU Outdoor Unit. This device sits between the Indoor Unit and the
antenna. It converts signals from one into the form needed by the
other.
OFDM Orthogonal Frequency Division Multiplexing. A method of split-
ting the data stream into a number of channels, each transmitted
simultaneously on a different frequency. Allows greater range
with less power, higher data rates, less distortion and greater im-
munity to interference.
OFDM Station Type Configuration setting where the base and remote are defined. The
APs are base stations. The CPEs are remote stations.
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Appendices