User's Manual

Glossary
BreezeMAX Modular Base Station System Manual 285
NIU Network Interface Unit
NLOS Non Line Of Sight. A condition where a signal from a wireless
transmitter passes several obstructions before arriving at a wireless
receiver. The signal may be reflected, refracted, diffracted, absorbed
or scattered. These create multiple signals that will arrive at a
receiver at different times, from different paths, and with different
strength. Consequently, wireless systems developed for NLOS
environment have to incorporate a number of techniques to
overcome this problem and that make the systems more complex
than those for LOS. But NLOS capable systems simplify network
planning and site acquisition.
NMS Network Management System. A system responsible for managing at
least part of a network. An NMS is generally a reasonably powerful
and well-equipped computer, such as an engineering workstation.
NMSs communicate with agents to help keep track of network
statistics and resources.
NOC Network Operations Center. The physical space from which a
typically large telecommunications network is managed, monitored
and supervised.
NPU Network Processing Unit
NRT Non Real Time. is very similar to the Real-Time polling service except
that connections may utilize random access transmit opportunities
for sending bandwidth requests. These Non Real Time Variable Bit
Rate (NRT-VBR) services, such as file transfer and Internet access
with a minimum guaranteed rate, are characterized by requirement
for a guaranteed rate, but can tolerate longer delays and are rather
insensitive to jitter. Service parameters include CIR, Committed
Time (CT), and MIR that limit the rate as otherwise bandwidth
intensive services may expand to occupy full bandwidth.
OA&M Operation, Administration & Maintenance. Provides the facilities
and the personnel required to manage a network.
ODU Outdoor Unit
OFDM Orthogonal Frequency Division Multiplexing: A method for
multiplexing signals, which divides the available bandwidth into a
series of frequencies known as tones. Orthogonal tones do not
interfere with each other when the peak of one tone corresponds
with the null. The rapid switching, frequency-hopping technique is
intended to allow more robust data service.