User's Manual

Table Of Contents
Installation, Operation and Service Manual 90DIB500R41IM_FCC02 99.1 61
DIB-500 R4.1 Product description
Constituents
The main control channel can be configured redundantly on any available carrier. If the
carrier that provided the main control channel last drops out, an alternative carrier will
take on this task. In this case, the replacement carrier will continue to send on its origi-
nal frequency, not on that of the failed carrier.
To ensure that the replacement carrier sends on the frequency of the failed carrier, the
following optional performance features can be used:
| "n+1 Carrier redundancy"
| "n+2 Carrier redundancy"
3.1.9.2 Transceiver redundancy
To increase the system stability of carriers or to ensure the Base Station Function
(BSF), as many as two redundant transceivers can be used in one base station. These
spare transceivers ensure the radio coverage on the frequency of the failed transceiver
if a transceiver drops out. Transceiver redundancy is mostly used in cased, in which
only a few frequencies are available.
3.1.9.3 Controller redundancy
When using base stations with at least two TIB transceiver modules (TETRA Indoor
Base Transceiver), the controller required for the Base Station Function (BSF) can be
designed redundantly. During the operation of the base station, both TIB transceiver
modules are active, whereby the controller of the first TIB controls regular base station
operation and the controller of another TIB is maintained in standby.
If one of the TIB transceiver modules or an Ethernet connection fails, the operationally
ready controller of the standby transceiver module is switched to active. In this way, the
operation of the Base Station Function (BSF) is continually ensured.
In base stations with at least two TIB transceiver modules, this performance feature can
also be combined with the optional performance features "n+1 carrier redundancy
("standby carrier")" or "n+2 carrier redundancy ("standby carrier")" and further increase
the fault tolerance.
The controller redundancy affects the Gradual reduction of the carrier capacity, refer to
section 3.1.9.4 on page 61.
3.1.9.4 Gradual reduction of the carrier capacity
ACCESSNET
®
-T IP provides the gradual reduction of the carrier capacity, which results
in low traffic capacity when the controller redundancy option for base stations without
carrier redundancy is selected. The operation of the base station is maintained while air
interface resources (carriers) are available with reduced capacity.