User Manual

ArchitectureNortel Networks Confidential 3–9
S8000/S8002/S8006 BTS Reference Manual
3.2 BCF functional architecture
Depending on the BCF physical architecture, the following functions are enabled
(see Figure 3–3):
control and switching
data channel concentrator
dual trunk interface
synchronization
alarm regrouping
3.2.1 BCF control, switching and management (CSWM)
3.2.1.1 Functions
The CSWM unit is duplicated for safety reasons, giving CSWMA and CSWMB.
The CSWM unit is the master BCF unit. It enables communication with the BSC,
organizes, stores and broadcasts all the data it receives from the BSC, supervises and
uses defense action on the equipment it controls. It must do the following (see
Figure 3–4):
set up communication with the BSC
manage BTS synchronization
manage the switching matrix
manage the FH bus
manage slave units (DSC, PCMI, ALCO, SYNC, GTW, and the TX part of the
TRX). Only the defense actions on slave processors is discussed below.
enable duplex operations
3.2.1.2 Setting up communication with the BSC
When the CSWM is activated, it must connect to the BSC to work. A link is set up
on an external PCM. Since a number of PCM links unite the BTS and BSC,
individual PCM links are frequently polled. If connection attempts fail on all the
available PCM, the CSWM resets.
3.2.1.3 Downloading
When the call has been set up with the BSC, the CSWM reports its status. The BSC
downloads the BTS if CSW code has not already been downloaded. The set of the
BCF downloadable files is formed by two catalogue files (BOOT & LOAD and
DLU), containing the list of the files, a configuration file and a file containing CSW
code.