User Manual

Architecture
Nortel Networks Confidential
3–36
PE/DCL/DD/0063
411–9001–063
Standard 12.07/EN September 2000
GSM/BSS V12
Event reports
The AMNU collects all events detected by the DRX equipment. It performs
filtration, and error reports to the BSC. Transmission error reports, and fault
management on RX–splitters alarms are sent through the BCF or CBCF.
The AMNU filters to prevent repetition of non–transient events, which means it can
send the BSC a single indication.
The AMNU sends errors to the BSC by sending ”event report” messages. There are
two types of these messages:
transient messages which are not acknowledged by the BSC
non–transient messages which must be acknowledged by the BSC and which are
repeated by AMNU until they are acknowledged.
Radio signaling function
The radio signaling function supports two Signal Processing Units (SPU). Each
SPU manages one time slot.
Two versions of the SPU software are available. One corresponds to propagation
conditions in rural area and the other to propagation conditions in urban area. For
the rural areas, the algorithm parameter equals zero where as it is set at the value
0.5 for urban areas. In this later case, the interferer cancellation algorithm is active.
The radio signaling functions can be broken down into four groups of functions:
level 1 radio access
level 2 radio management of LAPDm signaling
level 3 radio management, which is made up of two functions:
• radio resources management
• radio measurements management
operation & maintenance
Level 1 radio access
Level 1 radio access makes it possible to manage dialogue between the AMNU
signaling function and the SPU processors which are connected to the AMNU. It
offers:
configuration of operating modes for each SPU
SPU control
transmission and reception of data on the radio channel, respecting methods for
slaving to the radio frequency.
Level 2 radio management
Level 2 radio management manages the LAPDm level 2 signaling on the radio
channels.