Quantum and Evolution Series Installation and Operating Handbook
8-57
8.14 Paired Carrier
Paired Carrier
can be used to reduce satellite bandwidth requirements by up to 50% by
overlapping transmit and receive carriers in the same space segment. It uses ViaSat’s
patented PCMA technology. Adaptive self-interference cancellation is used to subtract the
unit’s transmitted signal from the composiste received signal, leaving just the desired
signal. This is depicted in the diagrams below.
Frequency Re-use by Overlaying Carriers
The
Paired Carrier
processing in the modem to cancel the unwanted signal in the
composite received signal to be left with only the desired signal is shown in the diagram
overleaf. The signal cancellation algorithm estimates and compensates for gain,
frequency, phase and delay in matching the unwanted component of the composite Rx
signal with a delay buffered version of its own transmission.
Typical satellite transmission
with separate frequency
slots for uplink and downlink.
Using
Paired Carrier
, uplink
and downlink carriers overlaid,
can save 50% on space
segment.
