User's Manual

BreezeCOMPACT System Manual
13
Chapter 1 - System Description The BreezeCOMPACT Solution
1.2.5 GPS
GPS is used to synchronize the air link frames of Intra-site and Inter-site located Base Transceiver Stations
to ensure that in all Base Stations the air frame will start at the same time, and that all Base Stations will
switch from transmit (downlink) to receive (uplink) at the same time. This synchronization is necessary to
prevent Intra-site and Inter-site interference and Base Stations saturation (assuming that all Base Stations
are operating with the same frame size and with the same DL/UL ratio).
In order for the system to be synchronized, the GPS have to first acquire at least 4 satellites. After that
the GPS reception can be reduced to 1 satellite. If no satellite is received the BTS will go to holdover state
where internal clock is provided to synchronize the BTS for up to two hours. Following a pre-configured
time in holdover state the unit will stop transmissions to avoid interfering with the operation of
neighboring units.
The all-outdoor GPS Receiver is a pole mountable GPS receiver and antenna in a single environmentally
protected enclosure. The receiver is powered from the unit, and it can be installed at a distance of up to
100m from the unit. GPS signals chaining (not supported in current release) enables using a single GPS
receiver for several colocated units.