1,196 research outputs found
Multiple-Input Multiple-Output Gaussian Broadcast Channels with Common and Confidential Messages
This paper considers the problem of the multiple-input multiple-output (MIMO)
Gaussian broadcast channel with two receivers (receivers 1 and 2) and two
messages: a common message intended for both receivers and a confidential
message intended only for receiver 1 but needing to be kept asymptotically
perfectly secure from receiver 2. A matrix characterization of the secrecy
capacity region is established via a channel enhancement argument. The enhanced
channel is constructed by first splitting receiver 1 into two virtual receivers
and then enhancing only the virtual receiver that decodes the confidential
message. The secrecy capacity region of the enhanced channel is characterized
using an extremal entropy inequality previously established for characterizing
the capacity region of a degraded compound MIMO Gaussian broadcast channel.Comment: Submitted to the IEEE Transactions on Information Theory, July 200
Secrecy Capacity of a Class of Broadcast Channels with an Eavesdropper
We study the security of communication between a single transmitter and
multiple receivers in a broadcast channel in the presence of an eavesdropper.
We consider several special classes of channels. As the first model, we
consider the degraded multi-receiver wiretap channel where the legitimate
receivers exhibit a degradedness order while the eavesdropper is more noisy
with respect to all legitimate receivers. We establish the secrecy capacity
region of this channel model. Secondly, we consider the parallel multi-receiver
wiretap channel with a less noisiness order in each sub-channel, where this
order is not necessarily the same for all sub-channels. We establish the common
message secrecy capacity and sum secrecy capacity of this channel. Thirdly, we
study a special class of degraded parallel multi-receiver wiretap channels and
provide a stronger result. In particular, we study the case with two
sub-channels two users and one eavesdropper, where there is a degradedness
order in each sub-channel such that in the first (resp. second) sub-channel the
second (resp. first) receiver is degraded with respect to the first (resp.
second) receiver, while the eavesdropper is degraded with respect to both
legitimate receivers in both sub-channels. We determine the secrecy capacity
region of this channel. Finally, we focus on a variant of this previous channel
model where the transmitter can use only one of the sub-channels at any time.
We characterize the secrecy capacity region of this channel as well.Comment: Submitted to EURASIP Journal on Wireless Communications and
Networking (Special Issue on Wireless Physical Layer Security
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