User Manual

Architecture
Nortel Networks Confidential
3–34
PE/DCL/DD/0063
411–9001–063
Standard 12.07/EN September 2000
GSM/BSS V12
Transparent messages are simply concentrated on a time slot of the internal PCM.
Non–transparent messages are:
radio measurement messages of the mobile
interference measurement messages on the inactive channels
load messages on the RACH channel
load messages on the PCH channel
Non–transparent messages are transcoded, averaged and grouped in a single
message to the BSC. This message is sent to the same time slot as the transparent
messages.
Operation & Maintenance functions
The following Operation & Maintenance functions are processed by the Frame
management unit (AMNU):
start–up, downloading, initialization
configuration
monitoring/defense
Start–up/Downloading/Initialization
The AMNU is started by a hardware reset or a reinitialization message sent by the
BSC. It causes configuration of the LAPD and establishment of the OML link with
the BSC.
The DRX subsystem can be downloaded only after that the BCF is downloaded and
that the units of site management of cell management and of Abis signaling of the
DRXs have been configured.
The BSC systematically initiates a downloading phase of the catalogue files and of
the following software units:
AMNU
SPU
DLU
BOOT
TX
BDT
BIST of the SPUs
Follows a re–flashing of the units for which the software versions are different.