Synchronizing Radio Base Stations; Figure 24: Clock Signal - Matra Nortel MC 6500 Manual

8.3

SYNCHRONIZING RADIO BASE STATIONS

DECT base stations are piloted by a common clock in order to transmit their radio frames
synchronously.
The various base stations within a radio system are synchronized with each other. If
synchronization is faulty or non-existent, the handover function will be impossible. There are
two methods of synchronization:
1. all base stations in the system are configured, by programming the MMCs, to use M-bit
of the S-frame and the sync signal is delivered by a card declared as "master"
2. one of the radio base stations in the system is configured as slave; it will generate the
DECT clock signal and send it to the other DECT radio base stations which are
configured as slave (by definition synchronization by the 3
This signal is a 800 ms differential clock signal and is shown below.
Three types of installation are possible (see appendix) with third pair synchronization:
1. Installation without repeater: 1 master base station sends the synchronization signal
directly to a maximum of 4 slave base stations.
2. Installation with REP16 (1 master base station, 1 to 4 repeaters, 64 slave base
stations).
3. Installation with REP96 (1 master base station, 1 to 4 repeaters, 384 slave base
stations).
Note: When the master base station synchronization signal is active, the green LED on
the repeater (16 and 96) blinks.
The master base station must be located as near as possible to the main
distribution frame.
Adjustment:
Compensation of the delay in the synchronization signal transmitted over the telephone
cable is set by MMC. The adjustment depends on the distance between the repeater and
the slave base station.
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800 ms

Figure 24: Clock signal

rd
pair)
4 ms
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