  We study the activated quantum no-signalling-assisted zero-error classical
capacity by first allowing the assistance from some noiseless forward
communication channel and later paying back the cost of the helper. This
activated communication model considers the additional forward noiseless
channel as a catalyst for communication. First, we show that the one-shot
activated capacity can be formulated as a semidefinite program and we derive a
number of striking properties of this capacity. We further present a sufficient
condition under which a noisy channel can be activated. Second, we show that
one-bit noiseless classical communication is able to fully activate any
classical-quantum channel to achieve its asymptotic capacity, or the
semidefinite (or fractional) packing number. Third, we prove that the
asymptotic activated capacity cannot exceed the original asymptotic capacity of
any quantum channel. We also show that the asymptotic no-signalling-assisted
zero-error capacity does not equal to the semidefinite packing number for
quantum channels, which differs from the case of classical-quantum channels.
