Ericsson MINI-LINK TN R3 ETSI Technical Description page 90

MINI-LINK TN R3 ETSI
The Diversity switches will work autonomous and are controlled by the switch
logic in the active MMU Rx. The switch logic is implemented as software in the
DP in the Control and Supervision block.
The Diversity switch will react on the Early Warning (EW) signals, Input Power
threshold alarm and FEC error alarm. The switch logic in one MMU needs
information from the other MMU, which is sent over the BPI bus.
Note that this switching is done under no fault conditions.
The switching principles are illustrated in Figure 74 on page 84.
MMU A
Cable
RAU A
Interface
MMU B
Cable
RAU B
Interface
Figure 74 Radio Segment Protection and Rx Equipment Protection
4.6.2.4 Rx Equipment Protection
This protection case involves two types of switch, TDM Rx switch and Diversity
switch.
The TDM Rx switch is a logical switch used to switch over the traffic to the
redundant MMU, in case of a failure in the TDM Demultiplexer part of the active
84
Radio Frame
Multiplexer
Modulator
Modulator
Radio Frame
Multiplexer
Diversity
TDM
Switch
Multiplexer/
Demultiplexer
Control and
Switch
BPI
Supervision
Logic
Control and
Switch
BPI
Supervision
Logic
TDM
Multiplexer/
Diversity
Demultiplexer
Switch
NPU
Node
Processor
4/1555-CSH 109 32/1-V1 Uen B 2007-09-14
TDM PCI
6667