  The fading broadcast channel with confidential messages (BCC) is
investigated, where a source node has common information for two receivers
(receivers 1 and 2), and has confidential information intended only for
receiver 1. The confidential information needs to be kept as secret as possible
from receiver 2. The broadcast channel from the source node to receivers 1 and
2 is corrupted by multiplicative fading gain coefficients in addition to
additive Gaussian noise terms. The channel state information (CSI) is assumed
to be known at both the transmitter and the receivers. The parallel BCC with
independent subchannels is first studied, which serves as an
information-theoretic model for the fading BCC. The secrecy capacity region of
the parallel BCC is established. This result is then specialized to give the
secrecy capacity region of the parallel BCC with degraded subchannels. The
secrecy capacity region is then established for the parallel Gaussian BCC, and
the optimal source power allocations that achieve the boundary of the secrecy
capacity region are derived. In particular, the secrecy capacity region is
established for the basic Gaussian BCC. The secrecy capacity results are then
applied to study the fading BCC. Both the ergodic and outage performances are
studied.
