User's Manual Part 3

RBS 2109 User’s Guide
LBO
Line Build Out
LED
Light Emitting Diode
LLB
Line Loop Back
LNA
Low Noise Amplifier
Local bus
The local bus offers communication between a central
main RU (DXU) and distributed main RUs (TRU and
ECU).
Local mode
When the RU is in Local mode, it is not communicating
with the BSC.
Local/Remote
switch
A switch used by the operator to order the RU to enter
Local or Remote mode.
LOF
Loss Of Frame
Logical Channel
A logical channel represents a specified portion of the
information carrying capacity of a physical channel.
GSM defines two major categories of logical channels:
• TCHs – Traffic CHannels, for speech or user data
• CCHs – Control CHannels, for control signalling
⇒ Physical Channel ⇒ Channel Combination
Logical RU
A unit which can be referred to, but is not a single
physical unit.
LOS
Loss Of Signal
LVD
Low Voltage Directive
LVF
Low Voltage Filter
MAC
Me
dium Access Controller
MADT
Mean Accumulated DownTime
magazine
A magazine is a reserved space in the cabinet, which
may hold one or more RUs.
Main RU
Contains one or more processors, to which software
can be downloaded from the BSC. A Main RU is either
Central (CMRU) or Distributed (DMRU). A Main RU may
or may not have a direct signalling link to the BSC.
MBU
Mounting Base Unit
231EN/LZT 720 0090 Uen R1A 2004-09-17