Huawei Airbridge BTS3612A-1900 Technical Manual page 14

Technical Manual
Airbridge BTS3612A CDMA Base Station
BASB
Figure 2-3 Structure of BCIM
BCIM comprises the following parts:
I. IMA module
IMA module inversely multiplex an ATM cell flow based on cells into multiple physical
links for transmission, and remotely multiplex the cell flows transmitted on different
physical connections into a single ATM cell flow.
In uplink direction, IMA module receives AAL2 traffic cells from BCPM and AAL5
signaling cells from BCKM through the backplane bus. It splits the ATM cell flow into
cells, transmits them on multiple E1/T1 link according to G.804 standard before
sending them to BSC.
In downlink direction, it receives ATM cells from BSC that are distributed on multiple
E1/T1 trunk lines, inversely multiplexes them into a single ATM cell flow. Then it sends
AAL2 traffic cells to BCPM and AAL5 signaling cells to BCKM through the backplane
bus.
II. CPU module
The CPU module implements such functions as IMA protocol processing, executing
OAM function of IMA, as well as E1/T1 link management and communication with
BCKM.
III. Backplane bus module
BCIM communicates with other boards in the baseband part through the backplane bus
module, including control information communication with BCKM and traffic data
communication with BCPM.
Data bus
Backplane bus CPU
module module
Clock
module
2-6
Chapter 2 Baseband Subsystem
RS232
IMA
E1/T1
module
Control bus
Power supply
module
System Principle
BCKM
BESP