Self-interference cancellation is provided in two-way relayed electromagnetic
communication between a first device and a second device through a relay station
wherein a representation of a relayed composite signal above baseband and a representation
of a locally modulated interface signal above baseband interact to effect the self-interference
cancellation. Specifically, the composite signal, which contains a relayed version
of the locally modulated (near) signal from the first device and a relayed version
of a modulated far signal from the second device, is received at the first device
from the relay station. The composite signal is then provided in a representation
as a first interface signal at a first frequency at or above baseband to a canceler
module of the first device and a representation of the modulated near signal at
a second frequency above baseband is provided as a second interface signal to the
canceler module. Part of the relayed version of the modulated near signal is canceled
from the representation of the composite signal using the representation of the
modulated near signal as provided to the canceler module to produce a third interface
signal as output at a third frequency at or above baseband. The first and second
frequencies may or may not be the same.
