  In this paper multi-antenna half-duplex and full-duplex relaying are compared
from the perspective of achievable rates. Full-duplexing operation requires
additional resources at the relay such as antennas and RF chains for
self-interference cancellation. Using a practical model for the residual
self-interference, full-duplex achievable rates and degrees of freedom are
computed for the cases for which the relay has the same number of antennas or
the same number of RF chains as in the half-duplex case, and compared with
their half-duplex counterparts. It is shown that power scaling at the relay is
necessary to maximize the the degrees of freedom in the full-duplex mode.
